SOME PLANT LICE
[[183]]
CHAPTER I
THE PENTATOMÆ AND THEIR EGGS
Of the forms which life is able to bestow on her creations, that of the bird’s egg is one of the simplest and loveliest. Nowhere do we find the beauty of the circle and the ellipse, the geometrical bases of organic bodies, combined with greater precision. At one of the poles is the sphere, the perfect form, capable of enclosing the greatest volume in the smallest envelope; at the other is the point of the ellipsoid, which tempers the monotonous austerities of the big end.
The colour-scheme, likewise very simple, adds its graces to those of form. Some eggs display the dull white of chalk, others the translucid white of polished ivory. The Wheat-ear’s are a delicate blue, like that of a sky freshly washed by a rain-storm; the Nightingale’s are a dark green, like that of a pickled olive; the eggs of certain Warblers are tinted with an exquisite carnation, like that of roses still in the bud.
The Yellow-hammer scrawls an indecipherable [[184]]scribble on her eggs; that is to say, the shells display mottled markings, an artistic mixture of lines and blots. The Butcher-birds encircle the large end with a speckled crown; the Blackbird and the Raven sprinkle brown splashes, innocent of design, on a greenish-blue ground; the Curlew and the Gull employ large spots like those on the Leopard’s coat; and so with the rest; each has its speciality, its trade-mark, always designed in sober colours, the mere matching of which constitutes a merit.
With the exquisite simplicity of its geometry and its ornament, the bird’s egg enchants the least cultivated eye. In return for the little services which they render me, I sometimes admit to my study certain small boys of the neighbourhood, zealous searchers all. Now what do these simple-minded youngsters see in my work-room, of which they have heard all sorts of wonders? They see big, glass-fronted cupboards in which a thousand curious things are arranged, the cumbersome accumulations that gather about any one who investigates stones, plants and animals. Shells predominate. [[185]]
Huddling together in mutual encouragement, my shy visitors admire the magnificent Sea-snails of every shape and colour; they point a finger at this or that shell which, by the lustre of its mother-of-pearl, its size and its strange protuberances, is especially conspicuous in the midst of all the rest. They gaze at my treasures and I watch their faces. I read on them surprise, amazement and nothing more.
These things out of the sea, too complex in formation to impress a novice, are mysterious objects that speak no known language. My little giddy-pates are bewildered by these corkscrew stair-cases, these scrolls and spirals and conchs, whose geometry is beyond their comprehension. They are left almost cold before this display of oceanic wealth. If I could get at what lies at the back of their minds, these children would say:
“How funny!”
They would never say:
“How pretty!”
It is quite another story with the boxes in which the birds’-eggs of the district are arranged, clutch by clutch, lying on cotton-wool, [[186]]protected from the light. Now their cheeks flush with excitement and they whisper, in one another’s ears, which they would choose of the finest group in the box. There is no amazement now, but ingenuous admiration. It is true that the egg recalls the nest and the young birds, those incomparable joys of childhood. Nevertheless, a rush of reverent emotion evoked by the beautiful may be read on their faces. The gems of the sea astound my little visitors; the simple beauty of the eggs arouses a more human ecstasy.
In the very great majority of cases, the insect’s egg is far from attaining this consummate perfection, which impresses even the unaccustomed gaze. The usual shapes are the sphere, the spindle or cone, and the cylinder, with rounded ends, none of which is especially graceful, owing to the absence of harmonious combinations of curves. Many of them are dingy in colour; some, by their excessive richness, form a violent contrast with the shortcomings of the germ inside. The eggs of certain Moths and Butterflies are beads of bronze or nickel. In these life [[187]]seems to germinate within the rigid walls of a metal box.
If we employ the magnifying-glass, we find that ornamentation of detail is not unusual, but it is always complicated, without that nobler simplicity which constitutes true beauty. The Clythræ[1] enclose their eggs in a shell whose substance is laminated in scales like those of a hop-cone, or twisted into intersecting diagonal fillets; certain Locusts engrave their spindles, scooping out spiral rows of little pits like those of a thimble. There is, to be sure, no lack of prettiness in all this, but how far removed is such exuberance from the noble austerity of beauty!
The insect has ovarian æsthetics of its own, which have no relation to those of the bird. I know of one case, however, in which comparison is possible. An insect of indifferent repute, a woodland Bug, the Pentatoma of the naturalists, may offer its egg for comparison with the bird’s. This flat-bodied insect, emitting a horrible smell, lays masterpieces of elegant simplicity, and, [[188]]at the same time, of mechanical ingenuity; it disgusts us by its cosmetic, its hair-oil; but it interests us by its egg, which is worthy to rank beside that of the bird.
I have just made a discovery on a sprig of asparagus. It is a cluster of eggs, about thirty in number, arranged in rows, in close contact, like the beads on a piece of embroidery. I recognize the eggs of a woodland Bug. The hatching took place some little time ago, for the family has not yet dispersed. The empty eggshells have remained in place without any loss of shape, except that their lids are open.
What a delightful collection of miniature vases in translucent alabaster, barely clouded with light grey! One would like to read a fairy-tale of the world of tiny things in which the fairies take tea out of such cups as these. The body of the vessel, a graceful oval cut square at the top, shows a delicate brown network of polygonal meshes. Imagine the top of a bird’s egg neatly removed, making a dainty little goblet of the remainder, and you have something very like the egg of the Bug. In either case there are the same gentle curves. [[189]]
Here the resemblance ceases. It is in the upper part of the egg that the insect displays its originality; its creation is a box with a lid. This slightly convex cover is ornamented, like the body of the jar, with a network of fine mesh; it is further embellished along the edge with an opal border. At the hatching it swings open as on a hinge and comes away all of a piece. Sometimes it falls off and leaves the jar wide open; sometimes it falls back into its normal position, once more closing the jar, which looks as though it were still intact. Lastly, the mouth is surrounded by very fine, thread-like attachments. These are, as it were, rivets to hold the lid in position, so as to close the vase hermetically.
We must not overlook one exceedingly characteristic detail. Quite close to the rim, inside the shell, there is always visible, after the hatching, a mark like a broad arrow, or a capital T, with the arms deflected like those of an anchor. What is the meaning of this infinitesimal detail? Is it a latch, a sort of lock with a bolt and hasp? Is it a potter’s mark, conferring a certificate of origin on the masterpiece? What a strange [[190]]effort of ceramic art merely to hold the egg of a Bug!
The young ones have not yet left the battery of jars from which they recently emerged. Gathered together in a heap, they are waiting for the bath of air and sunlight to harden them before dispersing and implanting their suckers where they please. They are plump, thickset, black, with the under surface of the belly red and the sides laced with the same colour. How did they get out of their jars? By what artifice did they raise the firmly-sealed lid? Let us try to find the answer to this interesting question.
It is the end of April. In the enclosure, just outside my door, the camphor-scented rosemaries are in full flower, bringing me visits from a multitude of insects which I can consult at any time. Various species of Pentatomæ abound, but do not lend themselves to precise observation, by reason of their wandering life. If I want to know exactly which egg belongs to which species or, above all, if I want to learn how the hatching is accomplished, it will not be enough to rely [[191]]upon chance inspections of the flowering shrubs. It will be better to resort to rearing the insects under a wire-gauze cover.
My captives, isolated according to species and represented each by a certain number of couples, give me hardly any trouble. All they need is a cheerful sun and a bunch of rosemary daily renewed. I add to the furnishing of the cage a few leafy twigs from various bushes. The insect will choose whichever suits her as the spot for laying her eggs.
By the first fortnight in May the imprisoned Bugs have provided me with eggs in excess of my hopes, eggs at once collected, together with their support, species by species, and placed in small glass tubes, where, unless I fail in vigilance, I shall easily be able to follow the delicate hatching-process.
It is really a beautiful, a most delightful collection, and would be quite worthy to figure beside the eggs of the bird, if larger dimensions came to the assistance of our feeble sight. From the moment we have to resort to the microscope, we allow the splendid to escape us. Let us magnify the Bug’s [[192]]egg under the lens and it will amaze us as surely as the Stonechat’s sky-blue egg, and perhaps even more. What a pity that such beauty escapes our admiration by its minuteness!
The shape is never a complete ovoid: that is the bird’s perquisite. The upper end of the Pentatoma’s egg is always finished off with a sudden truncation, into which a slightly convex lid is fitted, and we have before us a tiny ciborium, a delicious casket, an antique urn, a cylindrical cask with rounded ends, a full-bodied vase of Oriental porcelain, with ornaments consisting of bands, rosettes or traceries, varying according to the mother’s individual taste. Always, moreover, when the egg is empty, we find a most delicate fringe of herring-boned threads running round the mouth. These are the rivets to fasten the lid, which are pushed up and back at the moment when the new-born insect is released.
Lastly, in all these egg-shells, after the hatching, we find inside them, quite close to the rim, that black mark in the shape of a broad arrow, of which we have already asked ourselves whether it is a trade-mark [[193]]or a sort of lock or bolt. The future will show us how far our guesses fall short of the reality.
The eggs are never sown at random. The whole batch is laid in a close-packed group, in regular ranks of varying lengths, so that they make a sort of mosaic of beads firmly fixed to their common support, usually a leaf. They adhere so firmly that we may brush the leaf with a camel-hair pencil, or even touch them with the finger, without in any way disturbing their beautiful arrangement. After the young have gone we find the open shells still in position, like so many little jam-pots standing in rows on a market-woman’s barrow.
Let me end by giving a few specific details. The eggs of the Black-horned Pentatoma (P. nigricorne) are cylindroid in form, the base being a segment of a sphere. The lid, bearing a broad white band at the edge, frequently, but not always, has in the centre a transparent protuberance, a sort of knob like that on the lid of a preserve-jar. Its entire surface is smooth and glossy, with no other ornament than its simplicity. The colour varies according to the degree of [[194]]maturity. When recently laid the eggs are of a uniform straw-yellow: later, owing to the gradual organization of the germ, they turn a pale orange, with a triangular bright-red patch in the centre of the lid. When empty they are a magnificent, pellucid opal-white, except the lid, which has become transparent as glass.
Of the clutches of eggs obtained the most numerous was a patch of nine rows, each containing about a dozen eggs. The total was thus about a hundred. But usually the number of eggs is smaller than this, amounting to only half as many or less. Groups containing about a score of eggs are not uncommon. The enormous difference between these extremes testifies to multiple layings at different spots, which, in view of the insect’s rapid flight, may be at quite a distance from one another. This detail will be of value when the time comes.
The Pale-Green Pentatoma (P. praesinum) moulds her eggs in little barrels, ovoid at the bottom and adorned over their whole surface with a network of fine polygonal meshes in relief. Their colour is a sooty brown, and, after the hatching, a very [[195]]light brown. The largest groups of eggs contain thirty or so. It is probably to this species that the eggs belong which first attracted my attention on a sprig of asparagus.
As for the Berry Pentatoma (P. baccarum) here we again have barrels with rounded ends, covered all over the surface with a tracery of meshes. At first they are opaque and dark; then, being empty, they become translucent and white or pale-pink. Of these eggs I find groups of fifty and others of fifteen or even less.
That blessed plant of the kitchen-gardens, the cabbage, gives me the Ornate Pentatoma (P. ornatum), striped black and red. The eggs of this species are the prettiest of all in colouring. They are like little casks with the two ends convex, especially the lower. The microscope shows us a surface engraved with pits, like those of a thimble, arranged with exquisite regularity. At the top and bottom of the cylinder there is a broad dull-black band; on the sides is a wide white belt with four large black spots symmetrically placed. The lid, surrounded with snow-white filaments and edged with white, swells into a black dome with a central white spot. [[196]]In short, a funeral urn, with its violent contrast of coal-black and creamy white. The Etruscans would have considered it a magnificent model for their burial vessels.
These eggs, with their funeral ornamentation, are arranged in small groups, generally in two rows. There are hardly a dozen all told: a fresh proof that the eggs must be laid in a number of batches and at different points; for the Cabbage Bug cannot limit herself to this paltry number when one of her relatives exceeds the hundred.
May is not over before the various batches of eggs collected and placed in tubes hatch out, first one and then another. Two or three weeks are enough to develop the germ. This is the time for constant vigilance, if I wish to understand the mechanism employed for the emergence and, above all, the function of the strange tool, with the three black arms, which I find in every shell, at the edge of the opening, once the new-born larva has departed.
Those eggs which are translucent from the outset—for example, those of the Black-horned Pentatoma—enable me, in the first place, to discover that the implement of unknown [[197]]use makes its appearance rather late, when the approaching deliverance is announced by a change in the colour of the lid. It is not, therefore, an original part of the egg, as this descended from the ovaries; it is elaborated during the process of development, and even at a somewhat advanced phase, when the little Bug has already been formed.
We must therefore cease to regard it, as I did at first, as a spring, a lock, some sort of a hinge to hold the lid in place. An actual device for keeping the egg closed and protecting the germ would have to be in existence when the egg was laid. And it is just at the end, when the time has come to leave it, that the egg reveals this device. It is a question no longer of closing, but of opening. And, in this case, might not the puzzling implement be a key, a lever to force open the lid, held on by thread-like rivets, and perhaps also by the glue of an adhesive? Assiduous patience will tell us.
Holding the magnifying-glass above my test-tubes, which I examine every moment, at last I witness the hatching. The process is just beginning. The lid is rising imperceptibly [[198]]at one pole of its diameter; at the other it is tilting like a door on its hinges. The youngster has its back to the wall of the barrel, just below the edge of the lid, which is already gaping, a capital situation, enabling me to follow with some exactness the progress of the deliverance.
The little Bug, shrunken and motionless, has its head crowned with a skin cap, suspected rather than seen, so fine is it. Later, when it falls off, this cap will be plainly visible. It serves as the base of a trihedral angle. The three arms forming this angle are rigid and intensely black and look as if they ought to be of a horny nature. Two of them extend between the eyes, which are bright red; the third passes down behind the head and is connected with the others, right and left, by a dark, very fine line. I might very well regard these dark lines as tense threads, ligaments which brace the three arms of the apparatus and prevent them from slipping farther apart, thereby blunting the point of the angle, which is itself the key of the casket, that is, the rammer for pushing back the lid. This three-cornered mitre protects the head, which is [[199]]still soft and fleshy and incapable of forcing the obstruction: with its adamantine point truly applied right at the edge of the lid it has a firm grip of the disk which has to be unfastened.
This mechanism, this cap surmounted by an armoured point, must have its motive force. Where is it? It is at the top of the head. Look carefully, and there, involving a certain small area, almost a point, you will see rapid pulsations, we might almost say piston-strokes, produced, beyond a doubt, by sudden waves of blood. By hurriedly injecting what little fluid its body contains under its pliant cranium, the tiny creature turns its weakness into energy. The three-cornered helmet rises, pushing upwards, always pressing its point firmly on the same point of the lid. No blow is struck upon the tool; there is no intermittent percussion, but a continuous thrust.
The operation is so laborious that it lasts for more than an hour. By imperceptible degrees the lid is unfastened and rises obliquely, but as a rule continues to adhere to the rim of the vase at the opposite pole of the diameter. At this pivotal point, where [[200]]it would seem that there must be a hinge, the lens reveals nothing peculiar. Here, as every elsewhere, there is a mere row of threads, drawn down to form rivets for closing the cask. On the side opposite the point attacked, these rivets, less disturbed than the rest, do not quite give way, act as a hinge.
Little by little the tiny creature emerges from its shell. The legs and antennæ, economically folded over the thorax and abdomen, are completely motionless. Nothing moves, yet the Bug protrudes farther and farther from its casket, doubtless with the aid of a process like that employed by the larva of the Balaninus,[2] on leaving its nut. The flow of blood which causes the piston-strokes of the cranium distends also that part of the body which is already free and converts it into a supporting cushion; the hinder part, which is still imprisoned, is diminished accordingly and in its turn enters the narrow opening. The insect passes through a draw-plate, so gently and carefully [[201]]that the most I can detect is a tentative rocking to and fro at distant intervals as it drags itself from its socket.
At last the rivets are forced, the casket is open, and the lid, now on a slant, is sufficiently raised. The three-cornered mitre has done its work. What will become of it? Henceforth useless as a tool, it has to disappear; and, as a matter of fact, I see it discarded. The filmy head-dress which served as its foundation tears, becomes a tattered rag and very slowly slips over the Bug’s ventral surface, dragging with it the hard little black contrivance, which still retains its shape. Scarcely has this relic slipped midway down the belly when the tiny creature, hitherto motionless in the attitude of a mummy, frees its legs and antennæ from their economical position, stretches them out and impatiently waves them to and fro. It is over: the insect leaves its sheath.
The instrument of release, still in the shape of a T with arms bent slightly downwards and sideways, remains sticking to the wall of the shell, near the opening. Long after the insect’s departure the lens finds [[202]]the ingenious triangle in its place. Its formation is the same in the various Pentatomæ; but until we surprise the insect in the act of hatching its function is incomprehensible.
A word more on the manner of opening the lidded casket. I have said that the young Bug has its back to the wall of the little barrel, as far as possible from the centre. It is here that it is born, dons its tiara and afterwards pushes with its head. Why does it not occupy the central region, a position which would seem to be prescribed by the shape of the egg and the more effectual protection of the grub’s early frailty? Can there be any advantage in being born elsewhere, on the very circumference?
Yes, there is, and a very distinct advantage, of a mechanical order. With the top of its head, which throbs with the rushes of blood, the new-born insect thrusts his pointed cap against the lid to be unfastened. What can be the cranial thrust of a drop of albumen but lately congealed into a living entity? He would be a bold man who should venture to reply, so far is it beneath all evaluation. And this mere nothing has [[203]]to push open the solid lid of the box.
Let us picture the thrust applied to the centre. In that case the effort to dislodge the lid, the veriest trifle of an effort, would be uniformly distributed over the entire circumference, and all the rivets which fasten it would play their part in the resistance offered. Singly, the stitches would give way before the tiny force available; but all together they are invincible. The method of the central thrust is therefore impracticable.
If we wished to loosen a nailed plank, it would be an illogical action to bang it in the middle. The whole of the nails would react in a common and insurmountable resistance. On the contrary, we attack it at one end; we apply the leverage of our implement progressively to one nail after another. The little Bug in its casket does much the same: it pushes out the extreme edge of the lid, so that, beginning at the point attacked, the rivets give way, one by one. The total resistance is overcome because it is divided.
Well done, little Bug! You have your own science of mechanics, based on the same [[204]]laws as ours; you know the secrets of the lever and the lifting-jack. To break its shell, the nascent bird grows a callosity on its beak, a pick-axe point whose function is to break down the chalky wall piecemeal. When the task is accomplished this callus, the tool of a day, disappears. You have something better than the bird’s device.
When the hour of your emergence comes, you don a cap in which three stiff ribs converge to a point. At the base of this appliance your soft cranium acts like the piston of an hydraulic press. Thus attacked, the roof of your hut is unfastened and thrown back. The bird’s callosity disappears when the shell is in pieces; so does the mitre with which you push out the head of your barrel. As soon as the lid opens wide enough to let you pass, you doff your cap with its tripod of rods.
Your egg, however, is not broken; there is no violent demolition such as that practised by the bird. When empty, the egg-shell is not a ruin: it is still the graceful little egg that it was in the beginning, rendered yet more exquisite by its translucence, which enhances its beauties. In what school, little [[205]]Bug, did you learn the art of opening your natal casket and the use of your little contrivance? There are those who will say:
“In the school of chance.”
But you, in all humility, cock your mitre and reply:
“That’s not true.”
The Pentatoma is noted for another detail, which, if it were definitely proved, would surpass a hundredfold the marvels of the egg. I quote the following passage from De Geer,[3] the Swedish Réaumur[4]:
“The Bugs of this species (Pentatoma griseum) live on the birch-tree. In the early part of July, I found several of them accompanied by their young. Each mother was surrounded by a troop of young ones, to the number of twenty, thirty and even forty. She always kept close beside them, commonly on one of the catkins of the tree that contained her eggs, and sometimes on a leaf. I have noted that these little [[206]]Bugs and their mother do not always remain on the same spot, and that as soon as the mother begins to move away all her little ones follow her, stopping whenever the mother calls a halt. She thus leads them from catkin to catkin or leaf to leaf and takes them wherever she pleases, as a Hen does her Chicks.
“There are Bugs that do not leave their offspring; they even keep watch over them and take the greatest care of them while they are young. One day I happened to cut a young birch-branch peopled with such a family and I first observed the extremely uneasy mother, incessantly beating her wings with a rapid movement, without, however, stirring from the spot, as though to drive away the enemy that had just approached, whereas, in any other circumstances, she would at once have flown away or sought to escape, which proves that she was remaining only to defend her young.”
M. Karl de Geer has observed that it is chiefly against the male of her species that the mother Bug is obliged to defend her young, because he tries to devour them [[207]]wherever he comes upon them; and on such occasions she always tries with all her might to protect them against his attacks.
In his Curiosités d’historie naturelle, Boitard still farther embellishes the picture of family life painted by De Geer:
“It is most curious,” he says, “to see how the mother Bug, when a few drops of rain are falling, leads her young under a leaf or the fork of a branch to shelter them. Even there her anxious affection is not reassured; she drives them into a closely-packed flock, places herself in their midst and covers them with her wings, which she spreads over them umbrella-wise; and, in spite of the discomfort of her position, she retains this attitude of a brooding Hen until the storm has blown over.”
Shall I confess it? This umbrella made of the mother’s wings during showery weather, this procession of a Hen leading her Chicks, this devotion in warding off the attacks of a father inclined to devour his family leave me just a little incredulous, without surprising me, experience having [[208]]taught me that the books are full of little anecdotes incapable of surviving the ordeal of a strict investigation.
An incomplete observation, wrongly interpreted, sets the story going. Then come the compilers, who faithfully hand down the legend, the unsound fruit of the imagination; and error, confirmed by repetition, becomes an article of faith. What, for example, was not reported of the Sacred Beetle and her pill, the Necrophorus[5] and her work of burial, the Hunting Wasp and her game, the Cicada and her well, before the truth was arrived at? The real, which is perfectly simple, and supremely beautiful, too often escapes us, giving way before the imaginary, which is less troublesome to acquire. Instead of going back to the facts and seeing for ourselves, we blindly follow tradition. To-day no one would write a few lines on the Pentatomæ without dragging in the Swedish naturalist’s doubtful story, and no one, as far as I know, has mentioned the genuine marvels connected with the mechanism of the hatching.
What can De Geer have seen? The observer’s [[209]]high standing gives us confidence; none the less, I shall take the liberty of experimenting in my turn before accepting the master’s statements.
The Grey Bug, the subject of my story, is less frequent than the others in my neighbourhood: on the rosemaries in the enclosure, my field of exploration, I find three or four which, when placed under glass, do not give me any eggs. The set-back does not seem irreparable: what the grey refuses to reveal the green or the yellow or the red-and-black striped—one and all of similar formation and like habits—will show me. In species so closely akin, the family cares of the one must, in all but a few details, be reproduced in the others. Let us then note how the four Pentatomæ reared in captivity behave in the matter of their new-born young. Their unanimous testimony will convince us.
At the very outset I was struck by a fact which disagreed with what I had a right to expect in a future Hen leading her Chicks. The mother pays no attention to her eggs. When the last has been laid in its place at the extreme end of the last row, she makes [[210]]off, heedless of what she has left behind her. She does not trouble about it any more, does not return to it. If the hazards of her wanderings lead her up to it, she steps on the heap, crosses it and passes on, indifferent. The evidence leaves nothing to be desired: the coming upon a patch of eggs is an incident of no interest to the mother.
We must not attribute this negligence to the aberrations which may possibly occur in a state of captivity. In the perfect liberty of the fields I have come across many batches of eggs, perhaps including those of the Grey Bug; never have I seen the mother standing by her eggs, which she would have to do if her family required protection as soon as hatched.
The gravid mother is a quick flier and of a vagabond temperament. Once she has flown to a considerable distance from the leaf which has received her eggs, how is she to remember, two or three weeks later, that the hour for hatching is at hand? How is she to find her eggs again? Moreover, how is she to distinguish them from those of another mother? To believe her capable of such feats of clairvoyance and memory in [[211]]the immensity of the open fields would be midsummer madness.
Never, I say, did I detect a mother permanently posted beside the eggs which she had fastened to a leaf. Further, the total emission is split up into partial deposits dispersed at random, so that the whole tribe comprises a series of clans encamped here and there, often removed to considerable distances which it is impossible to specify.
To rediscover these flocks at the time of the hatching, which falls earlier or later according to the date of production and the degree of exposure to the sun; then, from all over the country-side, to gather into one herd the whole of her very frail and short-legged offspring: this were an obvious impossibility. Let us nevertheless suppose that, by a stroke of good fortune, one of these groups is found and recognized and that the mother devotes herself to it. The others are necessarily abandoned. They thrive none the less well for that. Why, then, should some of the young Bugs be so strangely favoured by maternal solicitude while the majority are able to do without it? Such peculiarities make one suspicious. [[212]]
De Geer speaks of groups of twenty. These, we are forced to believe, were not the complete family, but detachments sprung from a partial laying. A Pentatoma smaller than the Grey Bug has given me, in one single deposit, more than a hundred eggs. This fecundity must be the general rule where the mode of life is the same. Apart from the twenty watched, then, what became of the rest, left to their own devices?
With all due respect to the Swedish naturalist, the tender cares of the mother Bug and the unnatural appetites of the father eating his children must be relegated to the fairy-tales with which history is crammed. I can obtain, in my breeding-cages, as many hatchings as I wish. The parents are close at hand, under the same cover. What do they do respectively in the presence of the little ones?
Nothing whatever: the fathers do not hasten to slaughter their brats nor do the mothers hasten to their rescue. They wander to and fro on the wire trellis; they take their rest in the restaurant provided by a tuft of rosemary; they pass through the groups of new-born Bugs and topple them [[213]]over, without evil intent, but also without the least consideration. They are so small, the poor little wretches, and so feeble! A passer-by who grazes them with the tip of his foot turns them over on their backs. Like overturned Tortoises, they vainly kick and wriggle; no one heeds them.
Come then, O devoted mother! Since your family is beset by the danger of capsizing and other disagreeable accidents, place yourself at their head; lead them, step by step, into peaceful pastures; cover them with the buckler of your wing-cases! Any one waiting to observe these beautiful actions, these admirable and edifying moral characteristics, will waste his time and his patience. In three months of diligent watching I never saw, on the part of my charges, any action which in any way suggested the maternal solicitude so often extolled by the compilers of history.
Nature the universal nurse, alma parens rerum, is infinitely tender in her treatment of the germs, the treasure of the future; she is a harsh step-mother to the parent. As soon as the creature is capable of supporting itself, she delivers it without pity to life’s [[214]]cruel schooling, which teaches it to resist in the fierce struggle for existence. At first a tender mother, she gives the Pentatoma a delightful casket with a sealed lid to guard the budding flesh from harm; she caps the tiny insect with a mechanical device to set it free, a masterpiece of delicate ingenuity; and then, a stern schoolmistress, she says to the little one:
“I am leaving you. You must now fend for yourself in the hurly-burly of the world.”
And the little insect does fend for itself. I see the new-born Bugs, pressed close against one another, remaining for some days on the patch of empty egg-shells. Their flesh grows firmer and their colouring brighter. Mothers pass at no great distance: none of them pays any attention to the drowsy company.
When hunger comes, one of the little ones moves away from the group in search of a canteen; the others follow; they love to feel shoulder touching shoulder, like grazing Sheep. The first to move draws the whole band after him; they make their way in a flock to the tender spots where they insert their suckers and drink their fill; whereupon [[215]]all return to their native village, seeking a resting-place on the tops of the empty eggs. These expeditions in common are repeated within an increasing radius, till at last, having grown a little stronger, the community, becoming emancipated, makes off and disperses, no longer returning to the place of its birth. Henceforth each lives as he pleases.
What would happen if, when the flock is moving about, a mother were encountered, slow-stepping as the sober Bugs so often are? The little ones, I fancy, would confidently follow their chance-met leader as they follow those among themselves who are the first to make a start. We should then see something like the Hen at the head of her Chicks; accident would give all the appearance of maternal solicitude to a stranger quite indifferent to the mob of brats at her heels.
The worthy De Geer, it seems to me, must have been deceived by such meetings as these, in which maternal care played no part whatever. A little colouring, by way of involuntary adornment, completed the picture; and since then the domestic virtues of the Grey Bug have been lauded in all the books. [[216]]
[1] Cf. The Glow-worm and Other Beetles: chaps. xviii. and xix.—Translator’s Note. [↑]
[2] For the Nut-weevil, cf. The Life of the Weevil, by J. Henri Fabre, translated by Alexander Teixeira de Mattos: chap. vi; also his Social Life in the Insect World, translated by Bernard Miall.—Translator’s Note. [↑]
[3] Baron Karl de Geer (1720–1778), author of Mémoires pour servir à l’histoire des insectes.—Translator’s Note. [↑]
[4] René Antoine Ferchault de Réaumur (1683–1757), author of Mémoires pour servir à l’histoire naturelle des insectes and inventor of the Réaumur thermometer-scale.—Translator’s Note. [↑]
[5] Or Burying-beetle. Cf. The Glow-worm and Other Beetles: chaps. xi and xii.—Translator’s Note. [↑]
CHAPTER II
THE MASKED BUG
I met with this insect unexpectedly and in circumstances that hardly seemed to promise an interesting discovery. A certain enquiry into the spoilers of dead meat, an enquiry set forth elsewhere,[1] had brought me to the village butcher’s. What will not one do in the hope of securing an idea! The hunt after this rare quarry led me to the workshop of the slaughterer, an excellent man, for that matter, who did me the honours of his establishment to the best of his ability.
I wanted to see not the actual shop, so hateful to look upon, but the shed or what not in which the offal was collected. The butcher took me to the garret, dimly lit by a dormer-window which was left open night and day, in all weathers, to air the place. Continuous ventilation was not unwelcome [[217]]in that nauseous atmosphere, above all at the hottest time of year, when my visit was paid. The mere recollection of that garret is revolting to my senses.
Here, on a stretched cord, some blood-stained sheepskins are drying; in one corner is a heap of stinking tallow, in another are bones, horns and hoofs. These rags and tatters of death answer my purpose capitally. Under the shovelfuls of fat which I turn over, the Dermestes and her grub are swarming by the thousand; Clothes-moths flit indolently to and fro; and Flies with big red eyes keep on buzzing in and out of the hollow bones that still hold a little marrow. I expected this population, the habitual inmates of carrion refuse. But here is one which I did not anticipate: On the whitewashed wall are certain black patches of unsightly insects, gathered in motionless groups. Among them I recognize the Masked Bug, or Masked Reduvius (R. personatus, LIN.), a large Bug of some celebrity. There are nearly a hundred of them, divided into separate flocks.
The butcher watches me as I capture my discovery and put it into a box, and is surprised [[218]]to see me fearlessly handling the repulsive creature. It is more than he would ever venture to do.
“It comes and plasters itself against the wall,” he tells me, “and there it stays. If I sweep it off, next day it’s back, as sure as fate. I don’t say it does any harm. It doesn’t spoil my hides, it doesn’t touch my fats. What does it come here for every summer? I don’t know.”
“I don’t know either,” I reply, “but I shall try to find out; and, when I know, I can tell you about it, if you’d like me to. It may have something to do with the preservation of your hides. We shall see.”
Behold me then, as I leave this offal-store, the shepherd of a chance-met flock. They are not much to look at. Covered with dust, black as pitch, flat, like the true Bugs that they are, standing awkwardly high on their legs, lanky and skinny: no, they do not inspire confidence. The head is so small that there is only just room for the eyes, reticulated domes whose great prominence seems to indicate good powers of vision by night. It is set on an absurd neck which looks as though it had been strangled [[219]]with a bow-string. The corselet is jet-black, with burnished prominences.
Let us turn it over. The beak is monstrous. Its base covers all of the face that is not occupied by the eyes. It is not the usual rostrum, the drill of the sap-sucking Hemiptera; it is a rude implement, an elbowed tool, crooked like a bent forefinger. What can the creature do with this barbarous weapon? When it is feeding I see a black thread, as fine as a hair, issuing from the beak. This is the slender scalpel: the rest is the sheath and the stout handle. This rude equipment tells us that the Reduvius is an executioner.
What sort of exploits can we expect from it? Stabbing and murdering: actions of little interest, because of their frequency. But we must make a considerable allowance for the unexpected; interesting details sometimes lie dormant and spring up suddenly amid squalid surroundings. Perhaps the Reduvius has in store for us facts worthy of record. Let us try to rear him.
His weapon, a stout yataghan, tells us that the Reduvius is a murderer. What victim does he require? This is the rearing [[220]]problem before us. It so happens that some time ago I saw the dingy-looking Bug at grips with the smallest of our Cetoniæ, so well-named the Pall-bearing Cetonia,[2] because of her white spots on a black background. This accidental observation sets me on the right track. I house my flock in a large glass jar with a bed of sand, and as food I serve up the Cetonia aforesaid, which is common in spring on the flowers in the enclosure, but scarce at this time of year. The victim is very readily accepted. Next day I find her dead. One of the Reduvii, with his probe implanted in the joint of the neck, is working at the corpse and draining it dry.
In the absence of Cetoniæ I fall back upon any sort of game suited to the size of my boarders; and I find that any sort answers my purpose, irrespective of the different entomological orders. The usual dish, because it is the easiest for me to capture, consists of Locusts of medium size, though they are sometimes larger than the consumer. Often, too, for the same reason that he is easily obtained, it includes a Forest Bug, [[221]]Pentatoma nigricorna. In short, my charges’ diet does not give me much trouble: anything will do, provided that the prey does not exceed the powers of the assailant.
I was anxious to witness the attack, but I never managed to do so. As the big, prominent eyes of the Reduvius warned me, it takes place at night, at unseasonable hours. However early my inspection, I find the game lifeless, bereft of all power of movement. The hunter is feasting upon his prey and lingers over it for some part of the morning. Then, after many different applications of the probe, now at one point and now at another, when the victims are completely drained of moisture, the blood-suckers abandon the dead bodies, gather into a flock, and do not move all day long, lying flat on the sand at the bottom of the jar. On the following night, if I renew the victuals, the same massacres are repeated.
When the prey is a non-armoured insect, a Locust, for example, I have sometimes noted pulsations in the victim’s abdomen. Death, therefore, is not sudden and overwhelming; nevertheless, the quarry must be very quickly made incapable of resistance. [[222]]
I have confronted the Reduvius with a big-jawed Decticus, a Platycleis[3] five or six times the size of his executioner. Next day the colossus was sucked dry by the dwarf as quickly as a Fly would have been. A terrible stab had paralysed him. Where was the blow delivered and how did it take effect?
There is nothing to tell us that the Reduvius is a bravo versed in the art of murder, acquainted, like the Paralysing Wasps, with the anatomy of his victims and the secrets of their nerve-centres. No doubt he drives his stiletto at random into any part where the skin is soft enough. He kills by injecting venom. His rostrum is a poisoned dagger, like that of the Gnat, but much more virulent.
It is said, indeed, that the Masked Bug’s bite is painful. Wishing myself to test its effects, so that I might speak with authority, I have tried, but in vain, to get myself bitten. When placed on my finger and pestered, the insect refused to unsheath its weapon. Frequent handling of my specimens, without [[223]]the use of tweezers, was no more successful. On the evidence of others, then, and not from my own experience, I believe the Reduvius’ bite to be a serious matter.
It must be so, intended as it is to kill, swiftly an insect that is not always devoid of vigour. To the victim surprised when asleep it must mean the shooting pain and sudden numbness which the Wasp’s sting would produce. The blow is struck here or there, at random. It is possible that the bandit, once the wound has been inflicted, keeps his distance for a while and waits for the limbs to cease kicking before sitting down to devour the corpse. Spiders who have caught a dangerous prey in their webs are wont to take this precaution. They withdraw a little to one side and await the last convulsions of the fettered victim.
Though the details of the murder escape me, I know how the dead insect is exploited. I can witness the performance any morning, as often as I wish. The Reduvius projects from the clumsy scabbard, crooked like a fore-finger, a delicate black lancet, which is at once a probe and a suction-pump. The [[224]]implement is driven into any point of the victim’s body, provided that it be covered with skin. Then comes absolute immobility; the banqueter does not budge.
Meanwhile the lancets of the sucker are working, sliding one against the other, acting as a pump, imbibing the victim’s life-blood. In like fashion the Cicada drinks the sap of her tree. When she has drained one part of the bark, she moves on and sinks another well. The Reduvius does the same; he drains his prey at several points. He goes from the back of the head to the abdomen, from the abdomen to the neck, from the neck to the thorax and the joints of the legs. Everything is done economically.
I watch with interest the tactics of a Bug exploiting his Locust. Twenty times over I see him changing his point of attack and stopping for a longer or shorter time according to the wealth encountered. He ends up with a haunch, attacked at the joint. The barrel is emptied of its juices until it becomes translucent. If the quarry’s skin is diaphanous, the same degree of exhaustion may be perceived throughout the body. Thanks to the action of the infernal pump, a young [[225]]Praying Mantis an inch long becomes transparent as a moulted skin.
These blood-sucking appetites remind me of our Bed-bug, who makes himself so obnoxious by exploring the sleeper, selecting a convenient spot, leaving it for another and a more profitable, and again moving on, until, swollen to the size of a currant, he withdraws at the first glimmer of daylight. The Reduvius aggravates this method: he first benumbs his victim and then drains it dry. Only the legendary vampire of romance achieves a like degree of frightfulness.
Now, what was the insect-sucker doing in a butcher’s loft? He certainly did not find there the victims which I procure for him: Locusts, young Mantes, Grasshoppers, Chrysomelæ,[4] all lovers of foliage and the sunlight. These passionate lovers of open-air joys would never venture into the dark and nauseating offal-store. What, then, do these black squads clinging to the wall live upon? Such a crowd needs food, and plenty of it. Where is it? [[226]]
In the heap of fats, of course! Here a Dermestes (D. Frischii, KUGEL)[5] swarms promiscuously with her hairy larvæ. The supply is inexhaustible, and it is probably that the Reduvii hastened hither attracted by this abundance. Let us then change the bill of fare, let us substitute Dermestes.
I have just what is needed at my disposal without rushing off to the butcher’s for a supply. In the garden, at this moment, supported on reed tripods, there are certain aerial retting-vats in which Moles, Snakes, Lizards, Toads, Fish and so on attract interminable visits from the undertakers of the neighbourhood. The most numerous is a Dermestes, precisely the same as the one in the tallow-loft. This is the very thing I want.
I serve this Dermestes to my Reduvii, I serve him up lavishly. A frenzied massacre takes place. Every morning the sand in the jar is strewn with corpses, many of which are still lying beneath the murderer’s beak. The conclusion is obvious: the Reduvius kills the Dermestes whenever the opportunity [[227]]occurs; without having an exclusive taste for this sort of game, he bleeds it, more or less eagerly, when he comes across it.
I shall communicate this result to the worthy fellow to whom I owe the ingredients of this story. I shall tell him:
“Leave them alone, the ugly creatures whom you see sleeping on the walls of your loft; don’t drive them away with your broom. They are doing you a service; they wage war upon the others, the Dermestes, who are so destructive to hides.”
It may well be that the abundance of Dermestes, an easy prey, was not the motive which attracted the Reduvii to the butcher’s garret. Elsewhere, out of doors, there is no lack of game, in great variety and no less appreciated. Why do the Bugs prefer to gather here? I suspect that they wish to establish a family. The laying-season cannot be far away; and the Reduvius has come with the particular object of providing food and lodging for her offspring. In fact, at the end of June I obtain the first eggs in my jars. For a fortnight the Bugs continue to lay abundantly. A few mothers, reared [[228]]separately, enable me to estimate their fecundity. I count up thirty to forty eggs for each mother.
Here we no longer see the orderliness dear to the Forest-bugs, who arrange their eggs on a leaf so methodically, in rows of beads. Far from representing an extremely accurate piece of work, the Masked Bug’s batch of eggs is strewn, clumsily, at random. The eggs are isolated, adhering neither to one another nor to their support. In my rearing-jars they are scattered over the surface of the sand. Granular specks of which the mother has taken no care whatever, not even troubling to fasten them anywhere, they roll hither and thither, at the least breath of air. A plant is not more heedless of its seeds, which go where the wind blows them.
These greatly neglected eggs are nevertheless not without beauty of form; they are oval, amber-red, smooth and glossy and about a millimetre[6] in length. Near one of the ends there is a fine, dark, circular line, marking a sort of cap. The Forest-bug’s egg has taught us the meaning of this circle. [[229]]It is the line along which the lid of the casket will open. We have before us for the second time the tiny miracle of an egg shaped like a casket, which, on hatching, opens without breaking, by the fall of a little lid which is thrust back by the tiny creature in the act of birth.
If I can manage to see how the moveable cap is lifted, I shall obtain the most interesting detail of the Masked Bug’s history; I shall have the equivalent of the young Forest-bug bursting the ceiling of his shell by means of a sharp-angled mitre actuated by the hydraulic pulsations of the head. Let us stint neither time nor patience: the exodus of a Bug from his egg is a most notable sight.
If the problem has its attractive side, it also presents difficulties. You have to be on the spot just at the very moment when the lid gives way, which entails a wearisome vigilance. You also want plenty of light; and it must be daylight, or the refinements of this very delicate operation would escape us. The habits of the Reduvius give me cause to fear that the eggs may be hatched at night: [And the future will teach me [[230]]only too well how fully my fears are founded.] No matter: we will not give in. Perhaps fortune will smile upon me. And, lens in hand, for a fortnight, at all hours, from morning to night, I keep watch over a hundred eggs which I have divided among several glass tubes.
In the Forest-bug’s egg the approach of hatching is announced by a black line in the form of a broad arrow, or reversed anchor, which appears not far from the lid and is no other than the liberating mechanism. The tiny beast covers its head with its pointed mitre. Here there is nothing of the sort. From first to last, the Masked Bug’s egg retains its uniform amber colouring, without any sign of an inner lock.
Meanwhile, by the middle of July, the hatchings are becoming numerous. Every morning I find in my tubes a collection of tiny open pots, unbroken and amber-coloured as at the beginning. The lid, a concave dome of exquisite accuracy, is lying on the sand beside the empty egg-shell; sometimes it remains hanging from the edge of the orifice. The young Bugs, pretty little snow-white creatures, are gambolling nimbly [[231]]amidst the untenanted pots. I always come too late; what I wanted to see by sunlight is over.
As I suspected, the opening of the lid is effected in the darkness of the night. Alas, for want of sufficient light the solution of the problem which interests me so greatly will escape me! The Reduvius will keep her secret; I shall see nothing.… But yes, I do see something; for perseverance has unexpected resources. A week full of failures has already gone by, when, unexpectedly, in the brilliant light of nine o’clock in the morning, a few late-comers suddenly begin to open their boxes. Had the house caught fire just then, I doubt whether I should have stirred a limb. The sight held me rooted to the floor. Let the reader judge for himself.
Unprovided with the thread-like rivets employed by the Pentatoma, the Reduvius’ lid adheres to the shell by its mere position and a perfect fit. I see it lifting at one side and hinging on the other with a slowness that defies the magnifying powers of the lens. What is happening in the egg seems to be a long and laborious process. But the [[232]]lid opens wider; and through the chink I see something glistening. This is an iridescent pellicle, which protrudes, and, as it does so, pushes back the lid. Now a spherical blister emerges from the shell, gradually growing larger, like a soap-bubble blown from a straw. Pushed farther and farther back by the expansion of this bladder, the lid falls off.
Then the bomb explodes: that is to say, the capsule, inflated beyond the limits of its resistance, bursts open at the top. This envelope, an extremely thin membrane, usually adheres to the edge of the orifice, where it forms a high white rim. At other times the explosion detaches it and shoots it out of the shell. Under these conditions it is a delicate goblet, hemispherical, with torn edges, and with its lower part continued by a fine, twisted stem.
It is finished; the thoroughfare is open. The tiny insect can now emerge by bursting through the pellicle caught in the opening, or by dislodging it; or it may find an absolutely free passage, when the burst bladder has left the egg. It is all simply miraculous. To escape from his box, the Pentatoma invented [[233]]the three-ribbed mitre and the hydraulic ram; the Reduvius has invented the explosive bomb. The first goes to work gently; the second, a brutal dynamiter, blows the roof off his prison with a bomb.
With what explosive, and how is the liberating shell loaded? At the moment of rupture nothing visible bursts from the bubble; nothing liquid moistens the torn edge. The contents, therefore, were assuredly gaseous. The rest escapes me. One observation, which I was unable to repeat, is not enough in this delicate matter. Reducing it to mere probabilities I will propose the following explanation:
The tiny animal is wrapped in a tightly closed tunic which embraces it snugly. This is a temporary skin, a sheath which the new-born larva will shed on leaving the egg. This sheath is connected with an appendage, a capsule placed under the lid. The twisted stem hanging from the burst bubble when it is shot out of the egg represents the communicating duct.
Very slowly, as the little creature takes shape and grows, this bladder-like reservoir receives the products of the respiration [[234]]which takes place under the cover of the tunic or “overall.” Instead of dispersing outside, through the egg-shell, the carbonic acid gas incessantly resulting from the vital process of oxidization accumulates in this sort of gasometer, filling and distending it and pressing upon the lid. When the little Bug is mature and on the point of hatching, the increased activity of its respiration completes the inflation, which has doubtless been proceeding ever since the earliest development of the germ. At last, yielding to the increasing pressure of the gas-filled capsule, the lid becomes unfastened. The Chick in its shell has its air-chamber: the young Reduvius has its bomb of carbonic acid gas: it releases itself by breathing.
The singular hatching-processes of the Pentatoma and the Reduvius are obviously not isolated cases. The egg with a removable lid must be employed by other Hemiptera; it may even be that this is a fairly general device. Each genus has its own methods of opening its box, its own system of springs and levers. What a mechanism to find in the egg of a Bug, and how fertile [[235]]in surprises! What an interesting harvest to be reaped, with patience and a good pair of eyes!
Let us now watch the little Reduvius’ emergence. The lid fell off a few moments ago. The tiny insect, white all over, comes forth, tightly swaddled. The tip of its abdomen still remains within the opening, which, with its rim of skin, the remnant of the bomb, serves it as a supporting girdle. It struggles, swaying to and fro and leaning backwards. This gymnastic exercise, increasing the creature’s flexibility, is intended to undo the swaddling-clothes at the seams. Sleeves, breeches, gaiters, shirt-front, cap: little by little the whole is torn off, not without effort on the fettered pigmy’s part; it is all cast aside and disappears in tatters. Behold the new-born insect at liberty! It skips away to some distance from the egg. With its long, fine, waving antennæ it interrogates space, enquiring into this mighty world. Often, when the lid still adheres to some point of the opening, it carries this bit away with it, on its back or its rump. You would think it was going to the wars, bearing the umbo of antiquity, the round, [[236]]convex buckler. What does it want with this armour? Has it seized upon it as a means of defence? Not at all. The cover of the beaker happened to come into contact with it and at once stuck to it, even firmly, for nothing short of the approaching moult will detach the disk. This detail tells us that the little creature exudes a fluid capable of acting as an adhesive in respect of any light objects encountered on its passage—with what results we shall presently see.
With shield on back or without this panoply, standing high on its legs and sporting a long pair of horns, the new-born insect crosses the threshold of the egg; it roams about in sudden fits and starts, presenting the appearance of a minute Spider. Two days later, before taking any food, it undergoes a moult. The gormandizer, once he has eaten his fill, undoes a button to make room for the belated dainties concluding the meal. The Bug, who has as yet eaten nothing, splits his coat from top to bottom, throws it away, and puts on a new skin. He even changes his belly before sitting down to table. He used to wear a short, stumpy abdomen; he now has a plump, round [[237]]paunch. The time has come for feasting.
A restaurant-keeper with no experience of the proper bill of fare, what shall I provide? I remember a passage in Linnæus[7] touching the Reduvius. The master says:
“Consumit cimices lectularios huius larva, horrida, personata.” “Its horrid, masked larva sucks the Bed-bugs.”
This game seems to me out of proportion for the moment: the little creatures in my jars, weak and tiny as they are, would never dare to tackle such a quarry. There is another objection: the moment I want Bugs, I am unlikely to find any. Let us try something else.
The adult has eclectic tastes; it hunts the most varied prey. The larva might well do likewise. I offer Midges. They are absolutely refused. In the garret whence my flock originated, what could they have found that was easily obtained, without scuffling, so dangerous at that tender age? They would have found tallow, bones, hides, and nothing else. Let us give them tallow.
This time all goes well. My little creatures [[238]]settle down on the fatty substance, driving their suckers into it, drinking deeply of the stinking olein, and then retire to digest their meal in the sand, wherever they please. They thrive. I see them growing from day to day. In a fortnight they are plump, and, what is more, disguised beyond recognition. Their whole bodies, including the legs, are encrusted with sand.
This mineral bark began to form directly after the moult. The little creatures became speckled with earthy particles, thinly scattered at random. At present the envelope is continuous. Let matters take their course, and this wrap will become a sordid overall. Then the larva will really deserve the epithets which Linnæus bestows upon it: horrida, personata, the horrible insect that dons a mask and wears a dusty domino.
Should it occur to us to regard this tatter-demalion costume as an intentional piece of work, a ruse de guerre, a means of dissimulation whereby to approach its prey, we may undeceive ourselves: the Reduvius does not industriously make itself an overcoat; nor does it wear one with the object of concealing [[239]]itself. It all happens of itself, without any sort of art, like the mechanism whose secret was revealed to us by the lid of the egg, worn as a buckler. The insect exudes a certain unctuous humour, derived perhaps from the tallow on which it feeds. To this varnish, the dust through which it passes adheres without any further trouble on the insect’s part. The Reduvius does not dress itself; it dirties itself; it turns into a pellet of dust, a walking bit of filth, because it emits a sticky sweat.
One word more as to its diet. Linnæus, obtaining his information I know not where, makes the Reduvius our auxiliary against the Bed-bug. Since then, the books, monotonously echoing one another, have repeated the eulogy; it is accepted as a tradition that the Masked Reduvius makes war upon our nocturnal bloodsucker. This would certainly constitute a magnificent claim on our gratitude. But is it really the truth? I take the liberty of rebelling against tradition. That the Reduvius is sometimes found slaying Bed-bugs is very likely: my own captives were satisfied with Forest-bugs. They accepted them, however, without clamouring [[240]]for them; and they readily dispensed with them, seeming to prefer Locusts or any other insects.
Let us not then hasten to generalize and to look upon the Reduvius as a licensed consumer of the stinking pest of our beds. I see an important objection to this special vocation. Comparatively large in size, the Reduvius could not slip into the narrow chinks that shelter the Bed-bug. A fortiori, to track the Bed-bug to its lair is impracticable for the larva, hampered by its overcoat of dust, unless it invade our beds at the time when the other is running over us and selecting its morsel. Nothing justifies our presuming this intimacy with the sleeper; no one, that I know of, has surprised the Reduvius or its larva in the act of investigating our beds.
The masked larva does not deserve to be extolled for a few accidental captures. Its diet is quite different from what Linnæus tells us and the compilers keep on repeating. In its infancy it feeds on fatty matters, as my rearing-experiments prove. When it grows big it varies its victuals with insects, of no matter what order, as does the adult. [[241]]For it a butcher’s garret is an abode of bliss, where it finds a supply of fats, and, later, Flesh-flies, Dermestes, and other insects that batten on dead things. In the dark and ill-swept corners of our houses it gleans the particles of fat that fall from our kitchen-table; it catches unawares the drowsy Fly, the small, homeless Spider. This is enough to ensure its welfare.
Here is one more tradition to be deleted from our books, without much injury, however, to the insect’s reputation. If the Masked Bug ceases to appear in history as the executioner of the Bed-bug, it will henceforth cut a more respectable figure as the inventor of the box that is opened by the explosion of a bomb. [[242]]
[1] For the Bluebottle cf. The Life of the Fly: chaps. xiv to xvi.—Translator’s Note. [↑]
[2] Cf. More Beetles: chap. i.—Translator’s Note. [↑]
[3] Cf. The Life of the Grasshopper: chap. xiii.—Translator’s Note. [↑]
[4] Golden Apple-beetles, or Leaf-beetles. Cf. The Mason-Wasps, by J. Henri Fabre, translated by Alexander Teixeira de Mattos: chap. viii.—Translator’s Note. [↑]
[5] Bacon-beetles. Cf. More Beetles: chap. ii.—Translator’s Note. [↑]
[6] 1⁄25 inch.—Translators Note. [↑]
[7] Carolus Linnæus (Karl von Linné: 1707–1778), the Swedish botanist and naturalist, author of Systema naturæ, etc.—Translator’s Note. [↑]
CHAPTER III
THE TEREBINTH-LOUSE: THE GALLS
For curious methods of generation, the Plant-lice bear the palm. Nowhere shall we find anything to beat them unless we pry into the secrets of the sea. We must not look to them for remarkable feats of instinct. The humble, round-bellied Lice are incapable of such achievements; to these stay-at-homes the lifting of a foot spells an excess of emancipation. But they will tell us by what attempts, bewildering in their energy and variety, the universal law that governs the transmission of life has come into being.
I shall consult the Terebinth-lice by preference. They are near neighbours of mine, a condition essential to frequent visits; they practise an industry, which is a not uninteresting addition; and they are crowded into sealed enclosures where we can follow the progress of the family without too much confusion. [[243]]
The shrub that feeds them, the terebinth, or turpentine-tree, abounds on the Sérignan hills. It is sensitive to the cold, a lover of stony wastes scorched by the sun. Its insignificant flowers are succeeded by pretty bunches of little berries, first pink, then blue, smelling of turpentine and beloved by the Redstart when migrating in autumn.
Any one seeing it for the first time, unless conversant with its history, might think that it bore yet another crop of fruit, quite different from that of the berries. On the tips of the boughs, singly or in bunches, are certain twisted horns, a fairly good imitation of certain pimentos, if the coral-red of maturity were replaced by a straw-yellow washed with rose. What is more, mimic apricots, fresher and more satiny than those of our orchards, are seen hanging from the leaves. Tempted by appearances, we open these deceptive productions. Horror! The contents consist of myriads of Lice, swarming about in the midst of a floury dust.
Pilgrims to the Holy Land tell us that on certain bushes in the neighbourhood of Sodom beautiful-looking apples may be gathered, which are full of ashes within. The [[244]]pretty apricots and cornute pimentos of the terebinth-tree are the apples of Sodom, the Dead Sea fruit. Beneath an attractive exterior, they too contain nothing but ashes, live ashes, a wriggling whirl of dusty vermin. These are excrescences, galls, in which the opulent family of the Plant-lice lives isolated from the outer world.
To follow the progress of these strange productions I needed a terebinth which I could inspect often and in comfort. I happen to have one a few steps from my door. When I was stocking the enclosure with a certain amount of woody vegetation, I conceived the happy thought of planting a terebinth. A profitable tree, yielding acceptable fruit, would have died in this ungrateful soil; but this, which is good for nothing but firewood, is prospering excellently. It has grown into a magnificent specimen; and year after year it never fails to be covered with galls. So here I am, the fortunate possessor of a tree full of Lice. Let us call it by its Provençal name: lou Petelin, or lou Pesouious, the lousy one.
Scarcely a day passes but I give it a glance, attracted as I am by the daily happenings in [[245]]the enclosure. Let us examine it closely. The “lousy one” has its merits: it is the depository of interesting secrets. In winter it is bare. With the foliage the wigwams of Lice have disappeared, though towards the end of the summer they were weighing it down with their numbers. Nothing is left but the horn-shaped shells, now black and dilapidated ruins.
What has become of the vast population of the bush? How will it recover possession of its terebinth? In vain I inspect the bark of the trunk and branches and twigs: I see nothing capable of explaining the coming invasion. Nowhere are there any lice in a state of lethargy, nowhere any eggs awaiting the spring hatching. Nor are there any in the neighbourhood, nor, in particular, in the heap of dead leaves rotting at the foot of the tree. Yet the tiny creature cannot come from a distance: a mere atom, as I see it in imagination, does not go wandering across country. It is certainly on the tree that feeds it; but where?
One day in January, weary of my futile search, it occurs to me to strip off, in shreds, a lichen, the Wall Parmelia, which here [[246]]and there carpets thinly with its yellow rosettes the base and the thicker branches of my terebinth. I examine my harvest through the lens, in my study. What is this?
A magnificent discovery! In my scrap of lichen, no larger than a finger-nail, I discover a world. On the inner surface, in the winding crevices between the scales, are encrusted vast numbers of tiny red bodies barely a millimetre[1] in length. Some of them are entire and oval in shape; some, truncated and empty, display open pouches with pointed ends. All are plainly segmented.
Can it be that I have before my eyes the Louse’s eggs, of which some are old and empty, while others are recent and contain their germ? This idea is soon disposed of: an egg has not this segmentation like that of an insect’s abdomen. Here is a more significant fact: a head and antennæ are visible in front, while legs may be seen underneath; the whole is dry and brittle. These specks, accordingly, once lived and walked. Are they dead now? No, for when I crush them with the point of a needle traces of [[247]]moisture gush forth, a sign of a living organism. Only the shell is dead.
The tiny creature, capable at first of movement, endowed with legs and antennæ, wandered for some time under cover of the lichen; then, before it became inert, it settled down on a suitable spot. There it turned its shrivelled skin, now an amber-coloured pellicle, into a mummy’s sarcophagus in which the organism makes ready for a new life. When the time comes, we shall discover the origin of this curious object, which was an animal and now deserves the name of egg.
What my own familiar terebinth has shown me in the enclosure, I ought to see repeated in the open country. Sure enough, I do see it; but this time it is not under lichens, for the bark of the tree is most often bare. There is no lack of other shelter. Some twigs of terebinth have been cut by the clumsy bill-hooks of the brushwood-gleaners, leaving a ragged section. The wood is split into deep fissures; the loose bark comes away in tatters. Once dry, these ruins are a mine of wealth.
In the narrowest crevices, in the cracks of [[248]]the wood and under the splintered bark, there are great numbers of the atoms that interest me so greatly. To judge by their colour there are at least two kinds. Some are red; the others are black. These latter were scarce under the lichens on my terebinth; here they predominate largely. I collect some of both kinds. And now we must have patience. I have hopes that the answer to the riddle will be found.
Mid-April comes and the little glass tubes in which I store my animal seeds are full of life. The black germs are the first to hatch; a fortnight later the red ones follow suit. The epidermic boxes undergo a process of self-mutilation, the front part falling off and leaving a gaping void, without other change of form. A minute animal comes out of them, a black speck in which the lens recognizes a very shapely little Louse, bearing the regulation sucker pressed against its thorax. My first thoughts were correct: the puzzling little red and black bodies found under the lichens and in the cracks of dead wood were really Louse-seeds.
And these seeds, judging by their husks, endowed with a head and legs, are little insects, [[249]]first active and then inert and converted into germs. The original, almost integral substance is reborn in another shape. The little creature’s skin has provided the shell, the segmented box, a jet-black or amber-yellow pellicule; the rest is concentrated into an egg.
The time has not come to observe the singular creature’s origin and behaviour; chronological order forbids. Let us return to the vermin issuing from these germs. They are tiny, tiny little black Lice, with flat abdomens, plainly segmented and as it were granular. Assiduous observation through the lens shows them to be dusted with a touch of blue-grey powder like the bloom on a plum. Trotting with little steps about their spacious prison, the glass tube, they seem uneasy. What do they want? What are they looking for? No doubt, a camping-ground on the friendly tree.
I come to their assistance; I place in the tube a twig of terebinth whose buds are beginning to open at the top of their scaly covering. This is the thing they wanted. They climb up the twig, establish themselves in the velvet that clothes the tips of the [[250]]buds, and there they settle, calm and satisfied.
Direct observations made on the terebinth are accompanied, pari passu, by laboratory experiments. The little black Lice, rare on the 15th of April, are numerous ten days later. On the tip of a single bud I count over twenty of them; and most of the buds are colonized, or at least those that are largest and farthest from the ground. The occupants remain hidden in the scanty down of the nascent follicles whose tips are barely emerging.
After a sojourn of some days, when the leaves begin to appear, each insect makes for itself a private dwelling. It exploits, with its sucker, a leaflet whose tip turns purple, swells up and curls over, and, bringing its edges together, forms a flat pocket with an irregular opening. Each of these pockets, about the size of a grain of hemp-seed, is a tent in which a black Plant-louse takes up her residence: one only, never more.
What will the little Louse do in her isolated retreat? Feed, and, above all, multiply. If one is to become legion a few months hence, matters brook no delay. [[251]]Here, then, there is no father, a mere superfluity and waste of time. So many Lice, so many mothers; no more is needed. Nor is there any laying, for the egg would take too long to develop. Nothing short of direct procreation, unfettered by any preliminaries, is acceptable to the Louse’s ardour. The young are born alive and like their mother, except in point of size.
As soon as they are brought into the world, they insert their suckers, absorb a little sap, increase in size, and in a few days become capable of continuing the race by the same rapid method, without fathers. Until the end of the annual colonization the offspring, including the remotest degrees of descent, will maintain the process of genesis by direct parturition and will know no other method. When the time has come for a more convenient examination, we shall return to this amazing method, which completely upsets our ideas.
On the 1st of May I open some of the purple swellings which have formed on the tips of the burgeoning leaflets. Sometimes I find the maker of the capsule alone, just as she was on the tips of the buds; sometimes [[252]]she has undergone a moult and is accompanied by the beginnings of a family. After discarding her black slough, she has become greenish, corpulent and lightly dusted with flour. Her youngsters, at the moment one or at most two, are brown, slender and bare-skinned.
In order to follow the progress of the family, I place under a glass a couple of capsules which so far contain only the founder. Two days later I have a dozen young Lice, who soon desert the natal pocket and make for the cotton-wool closing the glass tube. This hasty migration indicates that the young Lice have their function elsewhere, on the tender, already unfolded leaves. Detached from its fostering support, the little purple cell dries up and its inhabitant dies. My census can no longer be continued. No matter: I have learnt that one day is enough to produce three births. If this birth-rate persists for a fortnight, the maker of the capsule will have brought forth a handsome family, gradually scattered over the wide field of exploitation offered by the terebinth.
A fortnight later the red eggs hatch out, when the young twigs are already shooting [[253]]and unfolding their leaves. As far as I could judge from my highly unreliable observations of these swarming insects, which are not clearly distinguishable one from the other, the later generation begins as did the earlier. It causes purple nodules to appear on the tips of the leaflets, little wallets similar in shape and size to a grape-stone. Like those already mentioned, these cells are inhabited at first by a single Plant-louse.
In both cases the rage for rapid multiplication is the same. The recluses soon produce offspring, who desert the natal shelter and proceed to settle elsewhere as colonists. At last, its flanks drained dry, the viviparous little insect dies in its withered arbour.
How many were they, coming from under the lichens and climbing to the assault of the terebinth? There were thousands of them; and this multitude is not enough. Hastily each Louse attacks her leaflet with her beak; she makes herself a lair out of its swollen tip and immediately gives birth to other Lice, multiplying ten- or perhaps a hundredfold in this invasion of the innumerable. The tree has now its full number of colonists, [[254]]all capable of founding populous tribes.
Are we to regard them as different branches of the same trade union, of the same family, exploiting the terebinth in various fashions, according to the point attacked? We hesitate to regard them as strangers to one another, when they are employed on the same work; yet there are significant reasons for concluding that we have here a duality or multiplicity of species.
Besides the disparity of the work accomplished, there is, at the outset, one distinctive feature: the colour of the eggs, of which some are black and others red. These vividly contrasted hues must correspond with independent ancestries. It is even possible that a patient examination, capable of analysing this minute object, would find differences in husks of the same colour. All my own searches beneath patches of lichen and in the crevices of dead wood end in nothing more than the discovery of two sorts of ovular carapaces but of two only, at least to judge by appearances; and yet on the tree we shall find five categories of workers who, though resembling one another, build very dissimilar structures. If there are no other [[255]]germs, germs which have escaped my careful observation, it would seem, therefore that the eggs have different contents under an identical shell, whether black or red.
Lastly, the configuration, that essential characteristic of the species, displays, in late autumn, very emphatic differentiating features. Up to this late season, the inmates of the galls of every form are so much alike that it is impossible to distinguish them one from another once they are taken from their dwellings. When the final exodus comes, at the close of the year, a generation makes its appearance which differs greatly from its predecessors, giving final proof of multiple species, to the number of five.
Their generic name is Pemphigus, which is to say, bubble, capsule, bladder. This scientific name is well deserved. The Terebinth-lice and some others that pursue similar callings, living on the elm and the poplar, are, in a word, artificers of swellings: by the incessant tickling of their suckers they cause the formation of hollow excrescences, which are at once board and lodging to the community.
On the terebinth, the simplest of these [[256]]dwellings consists of a lateral fold of the leaf, the edge of which is turned back over the upper surface and fastened to it without losing its green colour. This hem gives a very low-roofed dwelling: the floor and the ceiling meet. Therefore, being unduly confined, the family is not numerous. The timid maker of these green hems bears the name of Pemphigus pallidus, DERB. She is called pale because she has not the knack of painting her house purple.
Elsewhere the lateral fold, still turned over the upper surface of the leaf, grows much thicker, swells with fleshy tissue, develops wrinkles, assumes a crimson hue and becomes a short, hollow, spindle-shaped growth. This home, a fairly successful imitation of the seed-pods of the peony and the larkspur, belongs to the Pemphigus follicularius, PASS.
Elsewhere again the fold, which at first is made in the plane of the leaf, is now bent down at right angles under the leaf, becoming an ear-shaped appendage, a knotted, fleshy crescent, with a straw-yellow as its prevailing colour. This is the work of the Pemphigus semilunaris, PASS. [[257]]
The spherical galls take higher rank in the Plant-louse’s art. They are smooth, pale-yellow globes, varying in size from that of a cherry to that of an average apricot. They hang from the base of the leaves, which, despite these monstrous bladders, retain their normal colour, and, in all other respects, their normal shape. The insect which inflates these pretty capsules is Pemphigus utricularius, PASS.
But the most remarkable structures are the horn-shaped galls, truly Cyclopean monuments compared with their minute builders. Some attain a length of nine inches and are as thick as the neck of a claret-bottle. Grouped in threes or fours at the tips of the upper branches, they form barbaric trophies, twisted and fantastic danger-signals which might have graced the brows of some Alpine Ibex.
The other galls all fall off with the leaves; not a trace of them remains on the tree in winter, and even these firmly cemented to their bough, last for a long time. Only the protracted assaults of wind and weather will destroy them completely. The base itself does not easily disappear. Next year [[258]]it is still in its place, but dilapidated and reduced to the broken stump of a horn of plenty packed with the waxy felt that clothed the population in the days of its prosperity. In these palaces lived Pemphigus cornicularius, PASS.
The purple pitchers of the first phase are provisional stations in which the Lice prepare for wholesale colonization. Each of these humble cottages has its Plant-louse from the foot of the tree. The solitary, who was herself hatched from a germ, makes haste to give birth to live youngsters, who gradually spread over the new leaves, and die. Then the true galls come, the great cities which will provide room for several generations. Here again, all the five classes of specialists between whom we have discriminated set to work, all labouring independently at the first filling out of the cabins. Mutual assistance will come later.
May arrives; and already the simpler galls begin to grow: the lateral folds which, bent back upon the edge, become so many green hems. Beneath the awl of the black Louse, patiently pricking away at the leaf, a narrow border curves inwards from the [[259]]edge. The line of attack measures a couple of centimetres.[2] When it has worked long enough at this or that point, the tiny insect changes its place and goes elsewhere to begin all over again, standing motionless while its implement performs its functions.
Now what is the atom doing thus to warp what would be flat under natural conditions? Merely implanting its sucker. The prick of a needle, however skilfully guided, would bruise the tissues without affecting their form. The little insect must therefore instil a certain virus, which provokes an exaggerated flow of sap; it injects an irritant poison and the plant reacts by the swelling of the wounded parts.
And now the hem is growing wider, with a slowness that defies our scouting: as well try to follow with the eyes the growth of a blade of grass. It is now a slanting roof, a gaping fold. The Louse is in the angle, at her post, doing her duty as a turncock. With her fine probe she stimulates and controls the flow of sap. In twenty-four hours the roof completes its descent, pressing tightly against the leaf. It is a [[260]]lowered trap-door; but the mechanism of the structure works with such caution that the tiny insect, far from being crushed between the two thicknesses of leaf, retains its liberty of movement and moves about inside the fold as it would do in the open air.
A curious instrument, the awl of the little black Louse! With our modern machinery a child’s finger, applied to this or that lever, this or that valve, sets enormous masses in motion. Similarly, the Louse, with her delicate probe, sets powerful hydraulic machinery going and trims the sails of a leaflet. She is, after her fashion, an engineer on a gigantic scale.
The spindle- or ear-shaped galls make their first appearance on the edge of the leaves in the form of narrow crimson borders. Soon the walls grow thicker and become gnarled and fleshy, expanding into excrescences from which all green is excluded.
How is it that the part of the leaf treated by the Louse is naturally yellow and crimson, when, if simply folded, it retains its normal green hue unimpaired? Again, how is it that in the one case the thickness of the tissues is not increased while in the [[261]]other it becomes augmented? Why does the spindle keep to the plane of the edge, whereas the ear-shaped gall, or auricle, abruptly bends its leaf and hangs vertically? In all three cases, the implement is the same and the work differs profoundly. Is it the effect of a virus whose properties vary according to the sucker that inoculates it? Is it the result of a change of method in wielding the awl? We are confounded.
The problem becomes doubly obscure when we consider the spherical galls. Here the original black Louse settles just at the base of a leaf, on the upper surface, against the median vein. There she takes her stand, motionless and patient. The point abraded by the awl is hollowed into a tiny pit, which soon forms a small protuberance beneath the underside of the leaf. As though its foothold were gradually withdrawn, the insect dives and is swallowed up by a pocket whose opening closes of its own accord by the contact of its lips.
Here we have the Plant-louse at home, strictly isolated from the world. Though the edge of the fostering leaflet undergoes no alteration of shape or colour, the pitcher-shaped [[262]]appendage at its base turns a pale yellow and grows larger day by day, thanks to the centrifugal expansion provoked by the insect’s irritant sucker. The continual punctures of the solitary Louse and presently of her offspring will enlarge it, by the end of the summer, to the dimensions of a fair-sized plum.
The horn-shaped galls originate in an entire leaf, selected from among the smallest. On the tops of the boughs there are sickly leaves, the last achievements of an exhausted impulse. Scarcely unfolded and innocent of green, the colour of health, they measure barely a fifth of an inch in length. It is on these vegetable trifles that the enormous horn-shaped structures are based; and even so the leaf is not completely utilized, but only one of its lobes: in short, a speck, a mere nothing.
Exploited by the Plant-louse, this mere nothing acquires a peculiar energy. In the first place, it welds itself to the tip of the twig and becomes one with it, so that it lingers on the tree when the leaves fall and, with them, the other galls; next, it excites a flow of sap comparable with that of the [[263]]pumpkin-stalk nourishing its fruit. The very small begets the huge. The gall is at first a pretty little horn, regular in shape and green all over. Open it. The interior is a magnificent flesh-colour and soft as satin. For the moment, a solitary Louse, a black one, inhabits this attractive residence.
The five kinds of establishment have been founded, from the fold to the horn; they have only to grow larger as their population increases. Now what are they doing, these Lice immured in solitary confinement, each after her own fashion? To begin with, they are changing their clothes and their shape. They used to be black and slender, suitably built for wandering over the budding leaves: now they adopt sedentary habits, turn yellow and put on flesh. And now, with the sucker implanted on the wall, which is swollen with turpentine, they quietly give birth to their young. For them this is a continuous function, like that of digestion. They have nothing else to do.
Shall we call them fathers? No: the word would clash with the expression “giving birth.” Shall we speak of them as mothers? Not that either. The exact [[264]]meaning of the word prevents us. They are neither one nor the other, nor are they an intermediate form. Our language has no term to describe these animal curiosities. We must resort to the plants to acquire an approximate notion of the whole procedure.
In our parts, the common garlic scarcely ever flowers: cultivation has caused it to lose its sexual duality. It knows nothing of true seed, to which the paternity of the stamen and the maternity of the pistil contribute. Yet the plant multiplies readily enough. The underground part begets its offspring directly, that is to say, it produces large fleshy buds, gathered into a cluster of what is known as cloves. Each is a living embryo plant, which, when buried in the soil, continues its development and grows like the original plant. To multiply the garlic in his kitchen-garden, the gardener has no other resource than that of the cloves, the usual seed being here non-existent.
Some plants of the same alliaceous group are even more remarkable. They send up a normal stem, ending in what appears to be a spherical head of blossom. Properly this head should blossom into an umbel of flowers. [[265]]But this is not what happens. There are no flowers whatever; they are replaced by bulbils, a diminutive form of clove. Sexuality has disappeared: instead of seeds, announced by the preparations for flowering, the plant produces plantlets, concentrated into fleshy buds. On the other hand, the underground part has a lavish supply of cloves. Though the garlic is sexless, its future is assured; it will have no lack of successors.
To a certain extent, the genesis of the Plant-louse will bear comparison with that of the garlic. The strange insect also puts forth bulbils: that is to say, it is spared all ovarian delay and procreates live offspring without assistance.
The male is nobler than the female, says Lhomond.[3] This is a pedantic formula, generally refuted by natural history. In the animal kingdom, work, industry and ability, those true titles of nobility, are the attributes of the mother. No matter: let us accept Lhomond’s dictum; and, since we are allowed the choice, let us speak of the Plant-louse [[266]]as of the masculine gender, which is the nobler from the grammarian’s point of view. For that matter, nothing shall prevent us speaking of it as feminine, if our speech thereby gains in lucidity.
Isolated in his cell, the original Plant-louse, we were saying, grows a new skin and puts on flesh. He brings sons into the world, all of whose beaks play their part in enlarging the gall, while all their bellies are engaged in increasing the population. We are reminded of the avalanche which, at first a mere lump, becomes an enormous mass of snow.
When summer is over, in September, let us open a gall, no matter which, spread out the contents on a sheet of paper, take up a magnifying-glass, and see what there is to see. Folds, spindles, auricles, globes and horns afford us almost the same spectacle, allowing for numbers, which are here restricted and there enormous. The Lice are a magnificent orange yellow. The largest have stumps on their shoulders, the rudiments of wings to be.
All are clad in an exquisite cloak, whiter than snow, which projects some distance behind [[267]]them, like a train. This finery is a waxy fleece exuded by the skin. It will not bear the touch of a camel-hair brush; a breath destroys it; but the Louse despoiled of it will soon sweat out another. In the crowded gall, where so many individuals are huddled together, jostling one another, the waxen garment is often torn to shreds and pulverized. Hence a collection of floury rags, forming the downiest of beds, in which the tribe lie about.
Mixed higgledy-piggledy with the orange Lice we see others, much less numerous but easily detected. They are smaller, and are sometimes a rusty-red, sometimes a fairly bright vermilion. Always stocky and wrinkled, they are, according to the age and the pattern of the gall, either round as a Tortoise or shaped like a triangle with rounded corners. On their backs, they carry six to eight rows of white tufts, a waxy exudation, like the white smocks of the others. An attentive examination with the magnifying-glass is needed to detect this detail of their costume. They never sport the wing-stumps which the others acquire sooner or later.
One last characteristic, more important [[268]]than all the rest, places these pigmies in a category completely by themselves. From time to time I see on their backs a monstrous protuberance which mounts as high as the neck and doubles the creature’s bulk. Now this hump, which is here to-day and gone to-morrow, only to reappear later, is the conjurer’s wallet containing the future. When I manage to open one, without mishap, with the point of a needle, I extract from it a slimy speck displaying two black eye-spots, with traces of segmentation. My Cæsarean operation has laid bare an embryo.
I reserved the right to pass, grammatically, from the masculine to the feminine gender. And this is the time to do so. I isolate a few of the hunch-backed squaws in a small glass tube, with a scrap of gall. They give me young ones; and the humps disappear. The observation, unfortunately, cannot be continued: the scrap of gall withers and my specimens die. None the less it is now established that these pigmy Lice are mothers and that they carry knapsacks on their backs as incubating pockets.
The little red tortoises found in all the galls in the late summer are therefore as [[269]]prolific as the famous old woman who lived in a shoe: they alone bring forth young. All around them swarm their descendants, fat orange babies, who deck themselves in snow-white furbelows, suck the sap, distend their stomachs and prepare to grow wings in view of an approaching migration.
Are the hunch-backed mothers all the immediate daughters of the black Louse, the founder of the gall, or do they form a lineage at various removes? The latter seems probable in the horn-shaped galls, where the mothers are so exceedingly numerous. A single origin would not account for this prodigality. As for the other, far less thickly-populated galls, it seems to me that a single generation of red Lice would be sufficient.
Let me mention a few approximate figures. In the first week of September I open a horn-shaped gall, selected from among the largest. It measures eight inches in length by nearly an inch and a half in thickness at its greatest diameter. The population consists mainly of orange Lice, plump, smooth, and endowed with wing-stumps. These are the progeny of the tiny mothers. These latter are scarlet, stocky [[270]]and wrinkled, with their fore-part tapering and their hinder-part as if it were cut off short, so that their shape is almost triangular. As far as I can judge in the confusion of such a multitude, they should number some hundreds.
To estimate the whole population, I pack it into a glass tube eighteen millimetres[4] in diameter. The column thus formed occupies a height of 56 millimetres.[5] The volume, therefore, amounts to 16,532 cubic millimetres.[6] Therefore, allowing one Louse, roughly, to each cubic millimetre, the population of the gall is about sixteen thousand. As I cannot count, I gauge. Even so did Herschel[7] gauge the Milky Way. For numerical infinity, the Louse vies with the star. In four months the black atom, the first pioneer of the gall, has left all these descendants; and the end is not yet. [[271]]
[1] 1⁄25 inch.—Translator’s Note. [↑]
[2] A little more than ¾ inch.—B.M. [↑]
[3] The Abbé Charles François Lhomond (1727–1794), a famous French grammarian and classicist.—Translator’s Note. [↑]
[4] Not quite ¾ inch.—Translator’s Note. [↑]
[5] 2.18 inch.—Translator’s Note. [↑]
[6] 10 cubic inches.—Translator’s Note. [↑]
[7] Sir William Herschel (1738–1822), the Hanoverian-English astronomer, invented the principle of “gauging” the skies which was subsequently applied to the Milky Way by his son, Sir John Frederick William Herschel (1792–1871).—Translator’s Note. [↑]
CHAPTER IV
THE TEREBINTH-LOUSE: THE MIGRATION
By the end of September the horn-shaped gall is full, almost as full as a keg of anchovies. There would not be room for them all were the Lice to form only one layer, side by side, with their suckers implanted. They lie in strata according to the length of their probe: uppermost are the big Lice, in the second layer the medium-sized and between their legs the small ones, all of them motionless, with their trunks at work. Above those engaged in drinking is the shifting horde, seeking a place at the refreshment bar. Eddies occur in the crowd: those at the top dive down, those underneath return to the surface; and this continual ebb and flow gives each one time for a little tippling.
In this rough and tumble the white waxen finery turns to flour, which fills up the interstices and makes of the whole a swarming conglomerate in which the metamorphosis is [[272]]effected. Here, without a moment’s quiet, the moult takes place and not a leg is out of joint: here, when there is no free space, wide wings are unfurled and not a wing is torn. To achieve transfiguration without a hitch in such a tumult the insect must be peculiarly favoured by fortune.
The pot-bellied orange Lice are now handsome, black, slender midges, provided with four wings. Their secluded life is over; the time has come for soaring in the open air. But how will they get out? The internees are quite incapable of making a breach in the ramparts: they have no tools. Well, what the prisoners cannot accomplish the fortress itself will do. When the population is ripe the gall is ripe too, so closely does the calendar of the bush synchronize with that of the insect.
The hems raise their upper folds a little; the spindles open like so many purses, each lined with pink satin; the auricles part their thick gnarled lips. The doors open of themselves for the impatient inmates, by the mere action of the sap. In the other galls, the globular and horn-shaped ones, the mechanism does not work so easily; the unclosing is [[273]]a violent affair. More and more distended day by day, the globes burst their sides in star-shaped rents, while the horns split open at the top.
The exodus is worth close observation. I choose a few of the horn-shaped galls whose cracked tips announces the coming rupture. I expose them to the sun, in my study, facing a window, at a distance of a few paces from the closed casements. In the intervening space I set up a thick branch of leafy terebinth. I reckon upon this bait to attract the flying Lice, at least as a resting-spot. Next morning one of the horns opens, and by midday, in radiant sunlight, in calm, hot weather, the winged Lice are emerging.
They come forth in small companies, without hurrying. It is a quiet, gently-flowing stream. They are dusted over with a waxy flour, all that remains of the sometime powder-puffs. When barely on the threshold of the cranny, they spread their wings and are off, shedding a faint trail of dust from their shoulders, shaken by the vibrations of their wings. With an undulating flight they all make straight for the window, where the light is brighter than elsewhere. [[274]]They dash against the panes and slip down upon the cross-bars. There, bathed in the sunlight, without attempting to go further afield, they remain, collecting in a drift.
Although the rest of the room is thoroughly well lit in all directions, the flight of the departing Lice is always directed towards the window facing the sun. There are thousands upon thousands of them; and not one takes another path, veering ever so little to the right or left. You feel a certain surprise at the invariable route pursued by these atoms which, when released, in a space well lit on every side, all, from the first to the last, rush towards the delights of a ray of sunshine. A handful of shot dropped from a height does not return to earth with greater certainty. The leaden pellets are attracted by gravity, to which all dead matter is subject, while the specks of living matter obey the light.
My window-panes check them. In the absence of this obstacle, where would they go? Certainly not to the terebinth-trees near by. I have definite proof of this here, before my eyes. As a resting-place I have [[275]]set up a bough of the cherished bush. None of the newly emerged insects takes notice of it; none of them pauses there. If on the way to the window one of them collides with the green thicket and falls upon a leaf, it quickly picks itself up again and makes off in a hurry to join the others in the sunlit window. Freed henceforth from the demands of the stomach, they are no longer interested in the terebinth; they all avoid it.
The exodus lasts a couple of days. When the last loiterers have gone, let us open the gall entirely. The population has been rigorously sorted. At first it was a mixture of wingless red and winged black Lice. The latter have all left their dwelling; the others are still there. Those faithful to their home are small as before, squat, wrinkled and vermilion. Some of them bear the dorsal wallet, the maternal pouch. In them I recognize the legion of the mothers, now left alone in the house. For some time yet they linger on languidly, the gall being open to wind and weather; those less exhausted continue to produce offspring; mere abortions without a future; the time is too short and [[276]]the house is falling into decay. At length they perish, with their belated young. The gall is a deserted ruin.
Let us return to the emigrants, checked in their flight by the window-panes. In shape, colour and size they are all alike; the swarm is a monotonous repetition of the same individual; there is not one detail, however minute, to denote any difference. Yet we should expect to find males and females here. The Plant-louse, until this moment in the humble larval stage, has just acquired the attributes of the perfect insect. The heavy, pot-bellied Louse has become a slender midge, glorified by four iridescent wings. In any other insect this would be an infallible token of the nuptial frolics.
Well, in the children of the galls, these wings, these adornments of maturity, belie their promises. There is no wedding and there can be none. Not a Louse in all the swarm is endowed with sex, and yet each has her brood, which she brings into the world by direct reproduction as her predecessors did.
With a slip of straw moistened with saliva I pick up a winged Louse at random. I [[277]]press its abdomen with a pin. My brutal obstetrics produces an immediate effect: the insect’s outraged flanks eject a string of five or six fœtuses; and the process is repeated without variation no matter what specimen we deliver.
Let us, for that matter, consult the natural procedure. A couple of hours elapse and my prisoners behind the window are in the throes of childbirth on the glass of the panes, the plaster of the embrasure, the wood of the cross-bars. Matters become so urgent that any place suits them.
The Louse in the act of parturition raises her two large wings, the upper pair, and gently moves the two small ones, the lower pair. The tip of the abdomen bends downwards, touches the supporting surface and the thing is done: a fœtus is implanted perpendicularly to the support, with its head uppermost. A little farther away, a second is deposited as promptly, followed by another and yet others. In one brief sitting the distribution is over. The average number of the litter is six.
The infant, we were saying, is fixed in an upright position, at right angles to the supporting [[278]]surface. This nicely-balanced attitude is necessary. The new-born Louse is, in fact, wrapped in a thin tunic of which it must first of all divest itself. In a minute or two this swaddling band splits and is thrust backwards. The legs release themselves, kicking freely in all directions, which they could not do were the tiny creature lying on the ground. By this means joints that are working for the first time gain strength and suppleness. After a few moments of these gymnastic exercises, the tiny insect drops on its feet and wanders forth into the wide world.
While it is struggling in an upright position, passers-by sometimes knock it over, without consideration for its tender age. Then the danger is great. Thrown from its sticky pedestal, the little insect often perishes, incapable of casting off its slough. There are a few threads of cobweb in the corner of the window. Some winged Lice have been caught in them. The garlands of hanging Lice give birth to their offspring all the same, but the young ones, falling on the sill of the embrasure, cannot manage to strip, because they are not in a standing position. [[279]]
Soon the cross-bars of the window are peopled with vermin, jogging along with great activity, promiscuously with the winged Lice. What a to-do on the borderland of the invisible! What are they seeking, these busy atoms? What do they want? My ignorance will be their undoing. In two or three days the winged Lice die. Their part is played. That of the children is beginning. For some time yet the latter wander about, but at last nothing stirs at the window; the legion of Lice is dead. Before sweeping them away with a camel’s-hair brush, let us give a brief description of them. The new-born insects are pale green and slender in shape. Their length is not far short of a millimetre.[1] Nimble and standing fairly high on their legs, they trot about busily.
The globular galls burst and the hems, auricles and spindles begin to gape a little earlier than the horn-shaped galls, about the middle of September. The five gall-makers of the terebinth all have the same customs. After emerging from their open dwellings, all the adults, or winged black Lice, give [[280]]birth, within twenty-four hours, to a small number of young, some five or six, as do those of the horn-shaped galls.
The auricles yield a dumpy Louse, wider behind than before and of a dark olive colour. Her most remarkable feature is her sucker, which, folded underneath the insect, sticks out behind, recalling after a fashion a Grasshopper’s oviscapt. What can the puny creatures want with this mechanism? It is a sword, a sabre. Held erect, the implement would prevent any attempt at walking. To drive it into the food-plant, the insect apparently hoists itself on its legs, which correspond in length with the enormous probe. I should like to see this inordinate beak at work. My captives refuse what I give them: leaves and fresh galls. They lie huddled on the plug of cotton-wool which closes the tube. They have business to attend to. They want to get away; but to what?
Likewise squat of build, packed, not without a certain prettiness, into the shape of miniature Toads, the Lice from the globular galls are a pale yellowish brown, while those of the folded leaves are greenish black. [[281]]Neither the first nor the second have beaks of exaggerated length. That extraordinary rostrum, which sticks out behind, and, when at rest, resembles a caudal appendage, recurs in the young Lice from the spindle-shaped galls; but this time the little creature is oblong and its colour is pale green.
Let us cut short these dry details. It is enough if we recognize that these five fellow-guests of the terebinth are not of one race following different trades, but separate species. If the earlier generations, which all resemble one another, seemed to bear witness to a specific unity, the family of the winged Lice testifies to the contrary. These thickset insects and these slender ones; these bearers of the rostrum, sometimes of normal length and sometimes fantastically prolonged into the semblance of a caudal beak; these pale-green, olive-green, light-yellow insects are obviously independent forms.
A meticulous examination might find here preeminently all the characteristic features of the five categories; but the reader, repelled by prose descriptions, would soon turn the page. Let us pass on. Let us leave the insect laboratory, with its jars and test-tubes; [[282]]let us go out of doors to see how matters come to pass under natural conditions on the terebinth in the grounds.
The galls, frequently inspected during the hottest hours of the day, open before my eyes; the horns are splitting at the top, the globes are opening their sides, the others are parting their lips. The moment the fissure is wide enough the black emigrants appear, without haste, one by one, in absolute composure, despite the fierceness of the sun. The exodus was not accomplished with greater sobriety in the comparative darkness of my study. For a few seconds they linger in the breach; then, shedding a dusty trail from their floury backs, they spread their wings and are off. Their flight, favoured by the least breath of air, promptly carries them to a distance at which I soon lose sight of them.
As a rule the exodus is partial, being distributed over several days. When the whole swarm has disappeared there are still the wingless red Lice, the hump-backed pigmies, the progenitors of the big migrants. Some of them come to enjoy a little sunlight on the brink of the aperture. They soon go in again. Others follow them; perhaps they [[283]]too are attracted by the brilliant sunshine. Then we see none at all. The festival of the light is not for them. For a week or two longer they lead a hand-to-mouth existence in the ruined gall, but their end is not far off. The withered gall starves them and old age kills them where they stand.
So far there is nothing new: my laboratory experiments have already shown me what the terebinth in the garden tells me. The window-panes and test-tubes have even taught me more than the tree: they have enabled me to realize the part played by the winged Lice. In the liberty of the open air one fundamental detail of their story escapes me, for parturition takes place at a distance, I do not know where. The new-born Lice must be scattered everywhere, often at a considerable distance, as the emigrant’s flight informs me. Shall I then not find on the tree itself the little Lice with which my indoor observations have made me familiar? Yes: and in circumstances which are worth recording.
Let me recapitulate: to escape from their galls, strongly-built dungeons without any outlet, the Terebinth-Lice have no means of [[284]]breaking through. Though very clever at tickling vegetable tissues and making them swell into excrescences, they can do nothing with the walls of their prison. When it is time to go, however impatient they may be to get out, they must wait until the gall opens of itself, until the horn, in particular, splits into jagged segments at the top and the globe bursts open at the side. Until the fort is thus spontaneously dismantled, there is no possibility of escape.
Now it may happen that the winged population is ripe and ready to increase and multiply before there is a breach in the wall, either because the gall is not yet sufficiently distended, or because it has dried up before its time and is henceforth unable to open.
What do the captives do in the event of such a disaster? Precisely what they would do in the open air. Their business cannot be postponed. When the imperious hour has struck they bring forth their young, one on top of another, in such a crush that it is hardly possible to move. For good, or ill, the great task is accomplished.
In this tangle of wings a-flutter in the midst of a waxy powder, this skirmish of [[285]]legs seeking equilibrium on an ever-shifting support, many young Lice are trampled underfoot and injured, many are unable to strip and shrivel into grains of dust. The majority, none the less, so tenacious of life are they, contrive to escape in the swarming confusion.
Let us, in October, open a globular or horn-shaped gall which has dried up without bursting. We shall find it crammed with black Lice, all winged and all dead; a mass of procreators who have died after parturition. Beneath the heap of corpses, more especially against the walls of the dwelling, the lens, in amazement, discovers thousands of young ones. This is a new people: it is the future struggling amidst the cadaveric relics of the past; it is the progeny of the winged Lice, the family born in prison. Here and there, in the midst of this bustling youth, are vermilion-coloured specks, more awkward in their gait but as lively as the rest. These are the grandmothers of the colony, still doing fairly well and capable, I should say, of surviving the winter.
I have some hope of keeping them alive, they look so healthy. Perhaps their part is [[286]]not yet fully played. I set them aside, together with their galls, opened with a penknife. If left to the inclemencies of the weather in their ruined cells, they would die when the cold sets in; but may they not hold out if sheltered under glass? I almost think they will.
And indeed at the outset things do not go so badly. My little red insects continue to look in the best of health. Then, at the first frosts, they become motionless, though still fresh in appearance as though they meant to return to life in the spring. Appearances deceive; the motionless Lice never move again. Long before April the whole herd is dead. My care has slightly delayed the dissolution, without preventing the inevitable end. None the less I marvel at the tenacious vitality of the little red grandmothers. They live half the year, their daughters but a few days.
Released henceforward from the necessity of feeding themselves, the black emigrants, the winged Lice, leave their terebinth and need not search for another, as is proved by my bough, which, placed in the path of the emerging insects, does not even serve them [[287]]as a temporary resting-place. They seem equally heedless in selecting a spot for the establishment of their family. Before my window the young Lice are dropped at random, at any point to which the hazards of flight have led: on the window-panes, the plaster of the embrasure, the wood of the cross-bars or the threads of cobweb indifferently. There is nothing to show that the unfamiliar spot is regarded as inopportune. There is no sign of uneasiness, no attempt to fly off elsewhither, to a more propitious place. Soberly and serenely, the winged legion brings forth its young and goes its way.
In the open country things must happen no otherwise. The moment they are free, the emigrants shake off their waxen dust and flit away in this direction or in that, according to the prevailing breeze. A flying-machine has sprouted from their shoulders, a remarkable contrast to the clumsy paunch of their early days. Quick, for the sunlight, for flight, for the joys of the ballet in mid-air! Off they go, hovering as long as their feeble wings allow; then, wearied of merry-making in the sun, they alight on the first object that [[288]]offers, without henceforth renewing their flight as do my prisoners behind the closed window. Here, no matter what the nature of the site, parturition takes place. There is nothing left for them but to die.
With these urgent methods, disdainful of deliberate selection, the wastage among the emigrants’ tiny offspring must be great. On the bare soil, on stones, on dry bark, the little Lice undoubtedly perish. They need food quickly; and they are scarcely capable of wandering in quest of it themselves. Their sucker, sometimes of inordinate length, projecting beyond the tip of the abdomen like a caudal rapier, demands that the wearer shall erect it, shall drive it into some yielding source of sap. The insect must drink or die. In the test-tubes wherein I collect the young Lice born before my eyes, my captives die in less than a fortnight from want of food.
I try various kinds of green stuff. I have no success with any of them. But here, if direct observation fails me, logic comes to my assistance. There is no doubt that the tiny Lice, at the present moment the sole representatives of their race, must live [[289]]through the winter and serve as the origin of the population which will occupy the terebinth in the spring. These puny creatures cannot remain exposed to the severities of the winter. A shelter is indispensable, a shelter that will afford them both food and lodging. Where will they find it? Only one shelter is possible: it must be underground, beneath some sort of grass that will retain a little green in winter.
It is, in fact, to be presumed that the thick tufts of certain grasses will afford them shelter. This abiding-place, where the sucker will sink into the sweet root-fibres, and where the drip of rain or snow does not easily find access, is beloved by several Plant-lice. Those of the terebinth also may very well take up their winter-quarters there. As for what happens in these subterranean lairs, we are reduced to more or less probable conjectures. [[290]]
[1] 1⁄25 inch.—Translator’s Note. [↑]
CHAPTER V
THE DORTHESIA
After the exodus of the young, when she deserts her tent of swansdown, half a finger’s-breadth in thickness, very warm and soft, but blocked with rubbish which would hamper a second family, the Clotho Spider[1] proceeds to fashion elsewhere a light hammock with a canopy, an inexpensive summer-house where she will pass the remainder of the warm weather. Those who are not yet marriageable ask no better protection against the inclemencies of the winter; their robust powers of endurance are satisfied with a muslin tent under the shelter of a stone.
The matrons, on the other hand, as the heat begins to decrease, hasten to enlarge and strengthen their cells, lavishing upon them the contents of their silk-reservoirs, which the hunting-expeditions of the fine summer [[291]]nights have left distended. When the sharp white-frosts set in they will doubtless find more comfort in their luxurious mansions than in the first rickety hovels; nevertheless, they do not build them precisely for themselves but rather for the use of their expected offspring; wherefore the walls are never stout nor the feather-beds downy enough.
The superb structure of the Clotho is above all a nest, beside which those of the Chaffinch and the Siskin are but squatter’s huts. The mother, it is true, does not sit upon her eggs, being as she is without an incubator; she does not feed her offspring, who for that matter do not require her assistance; but the part which she plays is, none the less, one of exquisite tenderness. For seven or eight months she watches over her brood, protecting it with a devotion equal to that of the bird, or even greater.
Maternity, the supreme inspiration of the noblest instincts, has thousands upon thousands of masterpieces to bear witness to its skill. Let us recall that of the Labyrinth Spider.[2] What a wonderful achievement is [[292]]the spacious building where the mother mounts guard about the star-shaped tabernacle, the family cradle! What an eminently logical stronghold is this rampart of silk reinforced by masonry, to protect the eggs from the probe of the Ichneumon-fly!
Similarly, each mother has her own defensive methods, which are sometimes the most ingenious inventions and sometimes devices of extreme simplicity. The strange thing is that the distribution of talents takes no account whatever of the insect hierarchy. Certain insects of the highest rank, protected by sumptuous wing-cases, or sporting lofty plumes, or attired in garments of imbricated gold scales, are almost or quite incapable of doing anything; they are magnificent duffers, whereas others, among the very humblest, and passing unperceived, amaze us by their talents when we grant them our attention.
But do not things happen likewise amongst ourselves? True merit shuns indolent luxury. If we are to turn to the best advantage the little good which may lie hidden within us, we must feel the incentive of need. [[293]]As long as nineteen centuries ago, Persius prefaced his satires with the lines:
Magister artis ingenique largitor Venter.
One of our proverbs repeats his views in terms a little less crude:
L’homme est comme la nèfle; il n’est rien qui vaille
S’il n’amûri longtemps au grenier, sur la paille.[3]
Insects are like ourselves. Necessity stimulates their wits and at times enables them to make discoveries which upset all our conceptions. I know of one, amongst the humblest and least well-known, which, to safeguard its progeny, has found the following strange solution of the problem: at the laying-season, the normal length of the body is trebled: the fore part is left at the service of the insect, which feeds, digests, roams about and shares in the joys of the sunlight; [[294]]and the hinder part becomes an infant’s crêche, a nursery in which the little ones are gently exercised.
This singular creature is called the Dorthesia (D. Characias, Latt). We find it from time to time on the Greater Spurge, which the Greeks used to call Characias and which the Provençal peasant of to-day calls Chusclo, Lachusclo.
A lover of the climate in which the olive flourishes, this spurge abounds on the Sérignan hills, in the driest spots, where its great blue-green tufts contrast with the poverty-stricken vegetation of the neighbourhood. Standing in a bed of pebbles which reflect the sun’s rays upon it, by its vigorous foliage it protests against the hardships of winter. Still, it is not devoid of prudence. When the foolish almond-tree is already abandoning its shivering petals to the north-east wind, the spurge, less hasty, continues to observe the weather and keeps the tender tips of its blossoms rolled up crosier-wise for protection. The worst frosts are over. Then, with a sudden urge of sap, the stems swell with a milk that burns like hot coals and the crosiers uncurl and straighten out into clusters of [[295]]dingy little flowers, at which the first Gnats of the year come to slake their thirst.
Wait a few days longer. As the weather grows milder, we shall see a numerous population slowly emerging from the heap of leaves that have fallen at the foot of the spurge. It is the Dorthesia quitting her winter quarters under the remnants of the old foliage, and climbing, gradually, by cautious stages, from the base to the topmost summits of the plant, where the joys of heat and radiant light await her, together with the delights of an inexhaustible feeding-bottle.
In April, or at latest in May, the ascent is completed; all the little creatures are assembled on the topmost tips of the branches, in close-packed groups, side touching side, after the fashion of the Plant-lice. A sap-drinker and endowed with a beak that acts as a gimlet, the Dorthesia is, in fact, related to the Aphides, whose sedentary and social habits she shares; but, far from reminding us in appearance of the plump, naked vermin which the rose-tree and so many other plants have made familiar to us, she is clothed, and her costume is one of unusual elegance. [[296]]
The orange Terebinth-lice, imprisoned in galls, whether horn-shaped or rounded like apricots, attach to their hinder parts a long train of extreme delicacy, which the slightest touch reduces to dust. In the Dorthesiæ, on the other hand, we see a complete garment, a close-fitting coat of indefinite length, though fragile and breaking off in particles under the point of a needle, just as a brittle rind might do.
Nothing could be prettier than the cloak of this large Louse, either in shape or in colour. It is a uniform dead white, more pleasing to the eye than even the white of milk. The forepart of the garment is a jacket of curly knots arranged in four longitudinal rows between which other, smaller knots are distributed. The hinder part is a fringe of ten slats gradually increasing in width and spreading outwards, not unlike the teeth of a comb. The breast is covered by a shirt-front formed of symmetrical plates and pierced with six neatly-rounded holes, through which the brown legs emerge, quite naked and unconstrained. This shirt-front and the curly mantle on the back together form a sort of sleeveless woollen waistcoat [[297]]with easy-fitting armholes. In the same way the hood is pierced by holes to give free play to the rostrum and the antennæ. All the other parts are covered by the white cloak.
This is the winter costume; it covers the whole body but does not extend beyond it. Later, when the laying-season draws near, the garment grows longer, as though the insect, which in reality cannot undergo further change, were growing at a furious rate and trebling its length. Gracefully curved like the prow of a gondola, the new portion is furrowed above by wide parallel grooves; underneath it is finely streaked, almost smooth. The end is cut off square. The magnifying-glass here reveals a transverse button-hole plugged with fine cotton-wool.
The material of the garment is everywhere brittle, fusible and inflammable; when laid on paper it leaves a slightly translucent mark. From these qualities we judge it to be a sort of wax, similar to beeswax. In order to obtain it in some other form than that of tiny particles removed from the insect, I collect a handful of Dorthesiæ and subject them to the action of boiling water. The waxen coverings melt and dissolve into [[298]]an oily liquid which floats on the surface; the denuded insects sink to the bottom. On cooling, the thin floating layer sets into an amber-yellow sheet.
This colour causes us a certain surprise. We began with a substance whose whiteness rivalled that of milk; and now melting gives it a look of resin. This is a matter of molecular arrangement and nothing more. To impart a proper whiteness to the yellow wax as it comes from the hive, the wax-chandler melts it down and pours the melted substance into cold water, thereby reducing it to thin flakes which he afterwards exposes, on wattled screens, to the rays of the sun. Further meltings follow, with a further production of shell-like flakes and further exposure to the bright sunshine; and, little by little, the wax turns white by changing its molecular structure. In this art of bleaching how far our superior is the Dorthesia! Without treating the material by repeated meltings and prolonged exposures to the sun, she then and there transforms a yellow wax into one of incomparable whiteness. She obtains by her gentle methods a result [[299]]that eludes the violent procedures of the laboratory.
Like beeswax, the Dorthesia’s wax is not collected in the outer world: it is a first product, exuded through the surface of the body. No manipulation is required to induce it to form itself into curly knots, to fall into uniform streaks or graceful flutings. Merely in exuding from the pores of the skin, it automatically acquires the requisite form; like the fledgling’s plumage, its clothing grows correctly by the mere activities of the organism; the wearer of the dress has no need to improve upon it.
The tiny creature, when it issues from the egg, is perfectly naked, and brown in colour. Soon, before leaving the mother and settling on the bark of the spurge to draw its first sips, it becomes covered with thinly-scattered white specks, which form the first outline of the future jacket. By slow degrees these specks increase in number and are produced into curly knots, so much so that the youngster, at the moment of its emancipation, is clad like its elders.
The exudation of the wax is continuous; [[300]]the white tunic is constantly growing larger and nearer to perfection. Therefore the insect, if I cunningly strip it bare, ought to be capable of clothing itself anew. Experiment confirms my expectations. Destroying her garments with the point of a needle and brushing them off with a camel-hair pencil, I completely denude a mature Dorthesia. The persecuted Louse comes forth in her poor brown skin. I isolate her on a sprig of spurge. In two or three weeks’ time the coat has been remade; not so full as the first, but large enough and of the regulation cut. With the wax which would have added to the original garment the insect has sweated forth another.
What is the use of this backward prolongation which trebles the actual size of the body? Is it merely an adornment? It is much more than that.
Let us, once April is here, detach and lay open this strange appendage. It is hollow, and full of an incomparable downy wadding; no feather-bed or eider-down could boast of so fine, so white a filling. In the midst of this magnificent eider-down some ovoid beads are scattered, some white and others [[301]]tinged with a ruddy brown. These are the eggs. The new-born insects are swarming amongst them, higgledy-piggledy; some are bare and brown, some are more or less speckled with white, according to the more or less advanced state of the coat.
On the other hand, let us watch the Dorthesia idly roaming about the spurge. At long intervals we shall see emerging from the orifice at the end of the padded pocket a young Louse, handsomely clad, and nimble in his movements, who chooses his place beside his mother and settles down, plunging his bill into the juicy bark. He will not stir again until the well is dry. Others follow him from day to day; and this goes on for months on end!
If we were guided only by these observations we should conclude that the mother was viviparous, given to dropping, here and there, living offspring, all ready dressed. Nothing of the kind: we have just found in the thickly-quilted pocket both eggs and young. Moreover, the laying and hatching of the eggs may be witnessed without difficulty.
In a glass tube provided with a sprig of spurge I segregate a few mothers whose [[302]]terminal wallet I have removed. Laid bare, the insect’s hind-quarters have no further secrets from us; I see, sprouting from them, a sort of white mildew, like an unshaven beard. This is the waxy secretion that sprouts from the insect’s hind-quarters, producing, instead of tassels, filaments of extreme fineness. It is thus that the down which fills the wallet must be produced. Presently, in the midst of this tuft of down, an egg appears, like those which we obtained by breaking into the maternal treasury.
This method enables me to estimate the size of the clutch. Two Dorthesiæ stripped bare behind and isolated, with provisions, in a glass tube, produced, in thirteen days, thirty eggs, or fifteen apiece, or rather more than one egg daily. As the process of laying continues for nearly five months, the total number of eggs for a single mother must be nearly two hundred.
The eggs hatch in three or four weeks’ time. The hatching is announced by a change in the colour of the egg, which from white becomes a bright reddish-brown. On leaving the egg-shell the infant Louse is reddish-brown and absolutely naked. Its appearance [[303]]is that of a very tiny Spider, the more so as its long antennæ look very like a fourth pair of legs. Before long, four longitudinal rows of tiny white tufts appear on its back, with bare spaces between them. This is the beginning of the waxen mantle.
The protracted period of egg-laying, which continues for four months or more, the comparatively quick hatching, and, finally, the gradual exudation of the Louse’s clothing, explain why white eggs and reddish-brown eggs, with naked youngsters and others more or less clothed, are found simultaneously in the maternal pouch. This pouch is a warehouse in which the Louse’s eggs are collected for months together.
Inside the pouch, in the depths of its luxurious padding, the young Lice are born, grow up, and clothe themselves in wax before risking the dangers of the open. The mother gently carries them from twig to twig of the spurge without troubling herself as to those that emerge from her pouch. One by one, as they feel themselves strong enough, they migrate, when their time has come, to settle down in the neighbourhood. The exit from their home is always open; [[304]]they have only to force their way through the barrier of down.
The Narbonne Lycosa carries her family about with much less tenderness and security. There is no shelter on the back of the Gipsy Spider, no safeguard against falls, which are frequent in such a scramble. The Dorthesia, more happily inspired, makes a box of the skirts of her mantle and a downy bed of her caudal tufts. To find an equivalent method we must go back from the Spurge-louse to the first-born of the Mammifers—Kangaroos, Opossums and others—who rear their young in a pouch formed by a fold of the skin of the abdomen. Coming before its time, the shapeless embryo fixes itself on the teat and completes its development in the maternal pouch or marsupium.
Let us make use of this term to denote the Dorthesia’s pouch. There is a great similarity between the two wallets, although the insect is superior to the mammal in this respect: Life often begins with excellence in the lowly and ends with mediocrity in the strong. In the original device of the marsupium [[305]]a Louse has done better than the Opossum.
With the object of following the history of my insects more conveniently than was possible under the blaze of the sun by the roadside, I placed before one of my study windows a fine clump of spurge transplanted into a capacious flowerpot. As a result of my diligence the plant was populated during the course of March by three or four dozen Dorthesiæ, all wearing more or less fully developed marsupia. My experiment in the domestication of plant and insect was extremely successful: the spurge did well, so its inhabitants prospered also.
The wallets became filled with eggs and then with young Lice, who, matured in the nick of time, and more numerous every day, emerged and spread themselves at will over the spurge. During the heat of the summer you might have thought it had snowed on the plant, so populous was the colony of white Lice. It contained thousands of new inhabitants, varying in size and easily distinguished from the mothers and foundresses by their smaller dimensions, but above all by the [[306]]complete absence of the marsupium, an addition which must develop very much later, after hibernation at the root of the food-plant.
Some are larger and others smaller, according to age, for the matrons still continue to procreate, but all wear the same costume and present the same appearance; yet certain differences, unnoticed at the time of my summary examination, should divide them into two groups, one very small, consisting almost wholly of exceptions, and the other forming the vast majority.
In August these differences become very plainly visible. On the tips of the leaves, here and there, are isolated a few Lice who are surrounding themselves with a fragile waxen enclosure, a sort of shapeless capsule, while the rest of the flock, nearly all, in fact, continue to drink, their bills plunged into the bark. Who are these solitaries, withdrawn from the world of drinkers? They are males, undergoing transformation. I open some of these fragile capsules. In the centre, on a downy bed like that which fills the wallets of the mothers, lies a nymph endowed with wing-stumps. At the beginning [[307]]of September I obtain the first males in their perfect state.
Strange creatures, in truth! Standing high on their legs, with long horns, they have the look of certain Bugs. The body is black and powdered with a fine waxy powder, the remains of the capsule in which the transformation took place. The wings are of a leaden grey, rounded at the tips, overlapping one another when at rest and protruding a long way beyond the extremity of the abdomen. To the rear is an aigrette of white filaments, very long and straight, composed, no doubt, of wax, like the cloak of the larval stage. It is a very fragile ornament: the insect loses most of it merely in wandering about among the few leaves in his glass prison, the tube in which I am observing him.
In moments of elation the tip of the abdomen rises between the lifted wings and the bundle of spokes spreads out fanwise. The insect is showing off, erecting his tail, like the peacock. To glorify his nuptials, he has attached a comet’s tail to his rump; he displays it fanwise, closes it, opens it again, making it quiver and glisten in the sunlight. [[308]]When the crisis of joy has passed his finery is folded up and the abdomen sinks down under cover of the wings.
The head is small, with long antennæ. At the tip of the abdomen is a short, pointed projection, a sort of hook, an implement of pairing. Of mouth-parts or rostrum there is absolutely not a trace. What would he do with them, this microcephalous coxcomb? He has changed his shape only to flirt for a moment with his neighbours of the other sex, to mate and to die. Moreover, the part which he fulfils does not seem to be particularly necessary. On the spurge in my study the female population of the second generation numbers several thousands, and I obtain, in all, some thirty males. Approximately, there are a hundred times as many females. The dandified wearers of the aigrette cannot suffice for such a harem.
On the other hand, they do not seem to be very eager. I see some who, on emerging from the ruins of their capsule, covered with powder, brush and wipe themselves a little, try their wings, and then, with a lazy flight, make for the window, which is closed to prevent their escape. The festival of the sunlight [[309]]is to them a greater attraction than the emotions of pairing. It is possible that the indifferent lighting of the room is in this case the cause of their coldness. In the open country, under the direct rays of the sun, they would certainly have displayed their finery amidst the marriageable females, and the business of pairing would not have lacked ardour. But even though the most favourable circumstances had conditioned the pairing, the exaggerated number of females, out of all proportion to the males, tells us that very few are chosen among many that are called: roughly about one in a hundred. Nevertheless, all produce offspring. With these singular creatures it is enough that a few mothers are fecundated from time to time, and the race continues to thrive. The impulse communicated to the elect is a heritage which is handed down for some considerable time, on condition that a few couples, year by year, restore to the community its exhausted energies.
A parasite frequently observed in Bee-hives, the Monodontomerus, has already shown us a similar example of the rarity of the males. Two tiny little creatures tell us [[310]]of a vast field yet to be tilled by our genetic theories. One day, perhaps, they will help us to unravel the obscure problem of the sexes.
Meanwhile the old mothers, the Dorthesiæ bearing the marsupium, grow day by day fewer on the spurge. Their ovaries exhausted and their wallets empty, they fall to the ground, where the Ants cut them to pieces. On the plant only those young mothers whose maternal pouches will not begin to make an appearance until the return of spring are visible nearly till Christmas. When the cold becomes severe the flock descends to the foot of the spurge, under the heap of dead leaves. They will come up again at the end of March, slowly climbing the spurge-plant, to acquire the rearing-pouch and begin once again the cycle of evolution. [[311]]
[1] Cf. The Life of the Spider: chap. xvi.—Translator’s Note. [↑]
[2] Cf. The Life of the Spider: chap. xv.—Translator’s Note. [↑]
Man is like the medlar: he is worth nothing
Unless he has ripened long in the granary, on the straw.
CHAPTER VI
THE KERMES OF THE OAK[1]
The nest, that notable expression of maternal skill and care, is rivalled by other modes of rearing which often reveal the most wonderful tenderness. The Lycosa drags behind her, hanging to her spinnerets, the wallet of eggs that bangs against her legs; and for half the year she carries about on her back her young, fore-gathered in a serried group. In like fashion does the Scorpion nurse her offspring on her back; for a fortnight she allows them to gather strength against the moment of emancipation. Exuding a white wax, the Dorthesia contrives at the tip of the abdomen an exquisite [[312]]muff into which the young are born, and in which they adorn themselves with cottony tufts and peacefully grow ripe for the exodus. The downy refuge, with its narrow opening, allows the secluded offspring to emerge, one by one, as they become capable of settling down upon the fostering spurge.
Lowly among the lowliest, the Kermes of the oak has invented something even better: the mother, transformed into an unassailable fortress, bequeaths to her family, as its cradle, her skin, toughened into an ebony bastion.
In May let us patiently examine, in sunny corners, the slender twigs of the holm-oak or evergreen oak. Let us also inspect that cross-grained shrub with small prickly leaves, known to the Provençal peasant as the avaus, and to botanists as the kermes oak. This wretched brushwood, which one can pass over in a single stride, is really an oak, a genuine oak, as is proved by its handsome acorns, set in their rough, prickly cups. We will gather our harvest here as well as on the holm-oak. But we shall pass by the ordinary or English oak; we should find on it nothing in the least like what we [[313]]are seeking to-day. Only the two species first mentioned will repay exploration.
On these we shall see, a few here and a few there, but never in abundance, certain globules of a glossy black, about the bigness of a moderate-sized pea. Here we have the Kermes, one of the strangest of insects. But is this an insect? Is it of the animal kingdom? The uninitiated would never suspect such a thing; he would take the object for a berry, some species of black current. The mistake is all the more natural in that the globule, if bitten into, cracks, and yields a sweetish flavour, offset by a slight bitterness.
And this all but delicious fruit, we are told, is of the animal kingdom; it is an insect. Let us look at the creature closely, through the pocket microscope. We look for a head, an abdomen, and legs. There is absolutely not a vestige of a head, nor of an abdomen, nor of legs; all there is to be seen is a sort of large bead, fit for that cheap jewellery which is made of jet. Is there not at least that division into segments, which is the documentary proof of the insect? No! A pebble is not more lifeless.
Perhaps we shall find on the under surface [[314]]of the globule, in the part in contact with the twig, some trace of animal structure? The bead comes away easily and without breaking, like a berry. The base is slightly flattened and powdered with a white waxy substance which acts as a cement and causes the bead to adhere to the twig. Soaked in alcohol for twenty-four hours this substance dissolves and leaves uncovered the part to be examined.
Careful examination with the lens fails to reveal on the base of the bead the legs, or claws, however minute, which would serve to establish the fact of animal life. Nor does it reveal the sucker which, implanted in the bark, would imbibe the sap, that indispensable aliment. Although less smooth than the back, this portion is as bare as the rest. One would say, in fact, that the Kermes adheres to the twig because it is cemented to it, but has no other connection with it.
This cannot be the case. The black bead feeds itself; it grows; and without cessation it pours forth a product which might be the work of the distiller. To make up for such expenditure it must at least possess a rostrum to perforate the juicy bark. It assuredly [[315]]does possess such an organ, but so small that my worn eyes are powerless to detect it.
At the very moment of detaching the Kermes from its support the implement of suction may possibly withdraw itself, shrinking into itself to the point of becoming invisible.
In that half of the sphere which lies toward the base of the twig, the globule is traversed by a wide furrow which occupies the greater part of the half-meridian. At the lower edge of this furrow, on the confines of the supporting base, is a narrow opening, in the shape of a button-hole. By this opening only is the Kermes in touch with the outer world. It is a gate which serves many functions, and first of all, that of a fountain of syrup.
Let us cull a few twigs of evergreen oak peopled by Kermes and place the cut ends in a glass of water. The foliage will remain fresh for some time—a condition which will suffice to ensure the insects’ welfare. We shall see, ere long, a colourless, transparent fluid which, in the course of a couple of days, collects itself into a drop equal in volume to [[316]]the flask from which it oozes. If it becomes too heavy the drop falls, but without flowing over the Kermes, for the outlet is as it were a postern gate. Another drop at once begins to form. The spring is not intermittent, but perpetual; uninterrupted it sheds its solitary tears.
With the tip of the little finger let us gather this drop from the still and taste it. Delicious! In taste and aroma it is very nearly equal to honey. If the Kermes were to lend itself to wholesale rearing as well as to the easy harvesting of its product, we should have in it a valuable sugar-refiner. But it is for others to exploit it with the needful diligence and devotion.
These others are the Ants, those patient harvesters. They make for the Kermes even more eagerly than for the Plant-louse or Green-fly. The latter is niggardly in the matter of yielding its ambrosia; the Ant has to solicit it with patience; tickling its paunch before she can obtain even a meagre sip from the tips of its tiny horns. The Kermes is a spendthrift. Fully consenting, and at any moment, it permits all comers to [[317]]quench their thirst from its cellar, and its liquid largesse is offered in streams.
The Ants, therefore, crowd about the distillery; they form quite a company; by threes and fours they lick the opening of the gourd-like vessel; and however high the Kermes is installed amidst the foliage of the oak, they possess a most wonderful power of discovering it. When I see one slowly climbing I have only to follow her with my eyes; she takes me straight to the Ant’s tavern. She is my infallible guide when, still in its early youth, the Kermes by its minuteness would escape the glance of an eye not warned and on the alert. Even the very tiny insects are perambulating taverns and are well frequented like the big ones.
On the tree, in the full liberty of the fields, the diligence of the Ants, collecting the syrup as it oozes forth, will hardly permit us to estimate the value of the spring. The little round barrel, incessantly drained dry, shows barely a trace of moisture round the bung-hole. We must take an isolated twig, far from thirsty drinkers, to determine the true value of this flask of nectar. Then, in [[318]]the absence of the Ants, we see the liquor collecting with considerable rapidity in a drop of surprising volume. The extravasated fluid exceeds the capacity of the beaker, and the trickling continues, as evenly and abundantly as before. The sugar-refinery is now in permanent business; when there is no syrup left there is still plenty to come.
The Ants rear the Plant-lice, their milch-cows. What herds they would amass, what incalculable benefits they would derive therefrom, if the Kermes could only be reared in captivity! But it is found only in isolated groups, which, for that matter, are not numerous in themselves, and it cannot be moved from spot to spot. Removed from its position it dies, unable to take root elsewhere. The Ants exploit it where they find it, without the slightest effort to gather together a flock of Lice in a leafy chalet. Their ingenuity wisely draws back when confronted by the impossible.
What is the purpose of this nectar, so plentiful and so highly appreciated by the connoisseur? Can it be that it flows forth for the benefit of the Ants? After all, why not? In virtue of their number and their [[319]]activity as harvesters, they perform a function of far-reaching significance in the general picnic of living creatures. As the price of their services, they are granted the horn-shaped nectar of the Plant-louse and the fountain of the Kermes.
At the end of May let us break open the black capsule. Beneath the envelope, hard and brittle, a hasty dissection shows us eggs: nothing but eggs. We looked for the apparatus of a distiller of liqueurs, for rows of retorts; we find only an obtrusive ovary. The Kermes is little more than a coffer bursting with germs.
The germs are white, and assembled to the number of thirty or thereabouts, in little groups or clusters, which remind us, as regards their arrangement, of the masses of seeds in the buttercup. Tufts of extremely fine tracheal filaments encompass the glomeruli, surrounding them with an inextricable litter which makes an exact count impossible. A rough approximation gives us a hundred. The total of the eggs would therefore be some thousands.
What does the Kermes want with this prodigious number of offspring? An alchemist [[320]]of the general food supply, it does as do so many others among the humble creatures predestined to the elaboration of nutritive molecules: by means of excess numbers it seeks to avert the extermination with which it is threatened. With its liquor it provides the Ant, an importunate guest perhaps, but not a dangerous one, with a delicious beverage; on the other hand, with its eggs it nourishes a consumer who would lead to the extinction of the Kermes, were it not itself subjected to a drastic thinning out.
It has so happened that I have found the lover of omelettes at work. It is a negligible little grub which creeps from one tiny cluster to another, emptying his eggs still enclosed in their natal sheath. As a usual thing it is alone; sometimes it has companions—two, three or more. Ten, according to my notes, is the largest number recorded by its holes of exit.
How did it find its way into the strong-box, armoured on every side with impenetrable horn? We may be sure that it was introduced while yet a germ through the button-hole aperture whence oozes the syrup. A mother must have chanced this way, who, [[321]]discovering the orifice, took a sip, and then, turning herself about, plunged her oviduct into the opening. Here, without use of violence, the enemy entered the citadel.
The enemy belongs to the tribe of Chalcidians, those zealous ransackers of entrails. An extremely rapid worker, she acquires her adult form and emerges from the shell in the early part of June. In comparison with the offspring of the Kermes she is a giant, being no less than a twelfth part of an inch in length. The narrow dormer-window by which the germ was introduced being no longer able to give it passage, the recluse, with his patient, steely tooth, opens a door of emergence for himself through the wall of the shell, so that the latter is finally pierced with as many round openings as there were fellow-feasters. When they have departed the coffer is empty; there is no trace left of the plentiful omelette.
This ravager of ovaries is of a deep bluish-black colour; dark, concave wings, closely pressed down after the fashion of the elytral apron, giving it a vague look of the Beetle family. The head is flattened, projecting beyond the corselet on either side; [[322]]the powerful mandibles are such as are needed to perforate the tough, leathery wall. The long antennæ, incessantly vibrating, bent at an angle, slightly dilated at the tip, are ornamented with a white ring. Dumpy and thickset, the tiny creature runs swiftly along, polishing its wings and brushing its antennæ; it is full of delight at having emptied the belly of a Kermes. Has it a name in our scientific catalogue? I do not know, and am not especially anxious to know. A label in barbarous Latin would afford the reader no more information than would a few lines of history.
June is nearly over. For some time the sugary oozing has ceased; the Ants no longer come to their restaurant, a sign of profound alteration within. The outer aspect, however, has undergone no modification. We still have the small, black, glossy sphere, smooth and firmly fixed on its base, which is whitened with wax. With the point of a pen-knife let us break open the ebony casket, at the upper pole, at a point opposite the point of adhesion. Its wall is quite as hard and brittle as the wing-cover of a Scarabæus. Within, not a trace remains of the [[323]]juicy pulp: the contents consist of a dry meal, a mixture of red and white specks.
Let us collect this powder in a small glass tube; let us reinforce our sight by a magnifying-glass, and examine it. The appearance of the stuff is amazing. This dust is moving, these ashes are alive, and with life so numerous that the very idea of computation becomes alarming. It is the legion of the uncountable. In safeguarding a Louse fecundity knows no limits.
By their white hue we may distinguish those eggs that are not yet ripe for hatching. Now, at the end of June, these are the less numerous. The others, coloured by the tiny creatures within them, are bright red or orange yellow. Preponderant over all is the collection of white specks, the tattered husks of the eggs which have been hatched.
Now these discarded husks are arranged in radiating clusters, just as were the germs in the glomerulus of the ovary. This detail informs us that there was no period of egg-laying; that is, not only were the eggs not conveyed to a point external to the mother’s body, but they were not even conveyed to any particular point of the enclosure [[324]]bounded by the carapace, by a common protecting roof. They were hatched on the very site of their formation. The bunches of eggs, their arrangement and position remaining unchanged, have become clusters of offspring.
The Psyche has already provided an example of that singular genesis which exempts the mother from the process of egg-laying, the family being hatched out on the spot occupied by the eggs. Let us recall the shapeless moth, whose appearance is even more miserable than that of the caterpillar. She withdraws herself into the husk of her chrysalid, and there she wastes away, swollen with eggs which will be hatched on the spot. The mother Psyche becomes a lifeless bag whence emerges her living family. This is likewise the case of the Kermes.
I witness the process of birth. The new-born insects are struggling to escape from their envelopes. Many of them succeed in doing so by leaving the delicate husk of the egg where it is fastened, still included in the radiating pattern. Others, no less numerous, drag their sheath from its place and for a long time trail it after them, hanging [[325]]to their hinder parts. It adheres so firmly that the tiny creature is able to cross the threshold of the shell with its moulted husk, completing its liberation in the open air. Thus it is that we find on the natal twig, at some distance from the maternal pill, numbers of white discarded husks, which, if one had not closely followed the progress of events, would give one reason to believe that the eggs were hatched outside the Kermes. These filmy envelopes are deceptive; for the whole family was hatched inside the coffer.
Having collected the living dust with which it is now filled, let us glance at the ebony box itself. The cavity is divided into two storeys by a transverse partition, a fine-spun relic of the dessicated animal. The individual substance of the Kermes was so little that it is now represented by a delicate film. The rest of the mass enclosed by the shell appertains to the ovaries. The upper storey is therefore occupied by the newly born no less than the lower.
It is easy to emerge from this latter compartment when the time of the exodus has arrived; at its base is an ever-open door, [[326]]a fissure shaped like a button-hole. But how is it possible to escape from the upper storey, separated from the other as it is by a partition? The newly-hatched young are so feeble, so tiny, that they would never be able to break through the membrane. Let us look more closely. The partition is pierced in the centre by a round manhole! The inhabitants of the lower storey can make immediate use of the door of their dwelling-house, the button-hole exit; those of the upper storey can reach it by means of the hole in the floor. Magnificent foresight on the part of the mechanism of the dessication! The mother Kermes, of whom no more is left than an unsubstantial ceiling, contrives in her substance a trap-door without which half her family would die imprisoned.
Owing to its minute proportions, the tiny insect all but escapes the unaided eye. A good magnifying-glass shows it as a tiny Louse, shaped like an egg, the large end of the egg to the fore, and in colour a delicate reddish brown. It has six very active legs. Its motionless future, its lifeless maturity, are prefaced by a quick, toddling walk. The [[327]]long antennæ are in constant vibration; on the hinder part of the body are two long, diaphanous cirri, which will escape remark unless we look for them with sustained attention. There are two black eye-spots.
In the small glass test-tube in which I am observing it, the tiny creature appears to be extremely busy. It strays hither and thither, the antennæ outspread and waving to and fro; it climbs, descends, and climbs again, wandering this way and that, colliding as it goes with the torn skins of the hatched eggs. It is making ready for departure, that is evident. This mere speck of life is about to adventure into the wide world. What does it want? Apparently a sprig of its food plant. I have had an eye to its requirements.
In the orchard is an evergreen oak, one single specimen, a small but sturdy tree some ten to twelve feet in height. About the middle of June, when the young are beginning to appear, I place there some thirty Kermes, still adhering to their supporting twig.
In spite of all my pains, it will be no easy matter to follow the peregrinations of the Kermes’ family, should it disperse itself [[328]]over the tree, as I suppose it will. The traveller is too small and the country to be explored too vast. Moreover, to examine the tips of all the boughs with the magnifying-glass, leaf by leaf, twig by twig, is impracticable; no one’s patience would suffice to the task.
A few days later I inspect those that are within my range. Many migrations have taken place, as is proved by the white filmy skins left by the roadside. As for the young, I cannot see them anywhere, neither on the bark of the twigs, nor on the leaves. Is it possible that they have all attained the inaccessible tips of the boughs? Or can they have gone elsewhere? This is the first problem to be solved, and it must be solved under such conditions that the emigrants cannot escape my gaze.
I transplant some young evergreen oaks ten to twenty inches in height, into flowerpots filled with leaf-mould. On the twigs of each young tree I fix, with a little drop of gum, five or six Kermes, taking especial care not to obstruct the door of emergence. This miniature artificial coppice is placed where it is sheltered from the fiercest heat [[329]]of the sun, in my study, facing one of the windows.
On the 2nd of July I witness a migration. At the hottest time of the day, about two o’clock, the new-born Lice leave their fortress in an innumerable swarm. The young Kermes emerge hastily from the door of their dwelling, the button-hole-shaped cleft; many of them dragging behind them the discarded husk of the egg. For a moment they stand motionless on the domed roof of their spherical house; then they scatter over the neighbouring twigs. Several of them climb upwards and reach the summit of the plant, without appearing to gain much satisfaction from their ascent; some of them climb downwards along their twig, so that I cannot possibly guess what objective the swarm is seeking. It may be that we are witnessing a brief period of disorder, due to the joy of the first few steps in a world of unrestricted freedom; the tiny creatures may be wandering at random, abandoned to the delights of emancipation. Let them do as they will; they will soon quiet down.
On the following day, indeed, I can no longer see a single Louse on the tree; all [[330]]have found their way downwards to the black leaf-mould in the flowerpot, not far from the main stem. This mould, recently watered, is rich in the savours of foliage which has rotted and fallen into dust. There, on a surface barely larger than one’s fingernail, the little creatures have gathered into a closely packed flock. Not one of them moves, so well satisfied do they seem with their pasture, or rather their watering-place. As far as I can see they are feeding, motionless in their well-being.
I do what I can to increase their felicity. To keep the place cool and to provide a little shadow I cover it with a few dead leaves from the evergreen oak, previously moistened in a glass of water. And now, little Lice, you must proceed after your own fashion; I have done for you all that I can!
I have just learned of one essential point of your history, one detail, without which all the rest of my investigations must inevitably have come to naught. My first conjectures, although perfectly reasonable, were unfounded. Instead of settling down on some twig, as their mother did before them, the young Lice descend to the ground at the [[331]]foot of their natal tree. There, in the midst of the mosses and dead leaves, they find a shelter offering some degree of coolness, which will nourish them with its exudations, at all events at the outset.
And what do they live upon later?—I am not in a position to say. For five or six days I find them on the same spot, a motionless flock. Not one of them leaves the flock, not one of them descends underground. Then their numbers begin to diminish; little by little they all disappear, evaporating as it were, returning to that nothingness from which they were so little removed. The flock of atomies has left not a trace.
Apparently the flowerpot with its evergreen oak did not sufficiently fulfil the conditions of prosperity. There should have been also some grasses with underground rootstocks: in short, a jungle of herbaceous vegetation, rich in superficial root-fibres in which the young Kermes would have implanted their suckers. Is this the trouble?
I continue my investigations in the open country, at the foot of some evergreen oaks which, I noted, were thickly populated in May. The families of Lice are certainly [[332]]there, within a fairly small radius, for the puny little creatures are incapable of a lengthy journey. I inspect the varied vegetation covering the ground beneath the trees; I dig, uproot, and patiently, lens in hand, examine one by one the roots and stems grubbed up. Repeatedly resumed, in winter as well as in autumn, my laborious investigations are fruitless; the tiny Louse cannot be found.
The following year, on the return of spring, I was to learn that the presence of vegetation at the foot of the tree is not a necessity. Let us go back to the evergreen oak in the orchard. I peopled its foliage with some thirty Kermes which had reached maturity. There emerged from it, caravan by caravan, a multitude of Lice. Now, at the foot of this tree and all around it, for a distance of some yards, the soil is perfectly bare. Not a blade of grass, not a weed of any sort, has sprouted on this surface, so recently excavated by the spade. As for the roots of the oak itself, it is, as far as I can judge, useless to take them into account; for they lie at depths which the tiny Louse could never attain. [[333]]
Yet in May the tree, hitherto exempt from Kermes, is covered with black pills. My sowing has prospered; the young Lice which emerged from the shells have passed the winter underground, and on the advent of warm weather have returned to the tree, there to transform themselves into globules. What did they live on in this ungrateful soil, which contains not a single root-fibre? Probably on nothing at all.
They descend to earth in search of shelter rather than refreshment. Their refuge against the inclemencies of winter is precarious indeed, if it consists, as everything seems to declare, in a few cracks in some lump of earth, not far from the surface. In a hard winter, how many of these ill-protected creatures must disappear? To the ravages of the devourers of new-laid eggs we must add the more dreadful depredations of winter; and thus it is that in order to preserve one life the Kermes gives birth to thousands upon thousands.
The remainder of its story is not easily discovered. It is now the beginning of April. My three children, the joy of my declining years, lend me the keen sight of [[334]]youth. Without their assistance I should abandon all thought of the chase, which I now propose to pursue on the confines of invisibility. The previous year certain thickets of evergreen oak, well within the reach of the observer, were marked down as being thickly peopled by the Kermes. At that time I marked every populated twig with a white thread.
It is here that my little collaborators patiently pursue their investigations, leaf by leaf, and twig by twig. After a brief glimpse through my lens the harvest is placed in a botanist’s specimen box; a more scrupulous examination will be made in my study, with all the conveniences which the observer may require.
On the seventh of April, just as I am beginning to despair of my investigations, the tiny insect crosses the field of my pocket microscope. This is she, actually this is she! Just as I saw her last year emerging from her natal shell, so once more I behold her now. No change whatever is visible: neither of aspect, nor shape, nor colouration, nor size. She goes bustling along as though [[335]]busy in the extreme, searching doubtless for a spot to her liking. At every moment the smallest wrinkle in the bark conceals her from sight. I place the twig that bears the precious atomy under a bell-glass. On the following day I expect a moult. The bustling little insect is replaced by a motionless corpuscle. This is the first stage of the globular Kermes. Fortune has only once vouchsafed me such a “find,” which would have been examined in greater detail had I possessed a sufficient number of subjects. My inspection of the evergreen oaks was somewhat in arrears; I ought to have made it in March. At this period, I imagine, I should have caught the insect emerging from the soil and returning to the foliage of its oak-tree, in order there to undergo transformation. Instead of one single subject I should have had many, though even then I could not have counted upon a numerous collection, for the hardships of winter have certainly thinned out those families, which were in the beginning so numerous. They descended from the tree in their hundreds of thousands; they [[336]]climb it again in scanty groups, as is attested by the scarcity of the black globules in the warm weather.
As for what becomes of the climbers, my single specimen tells us plainly enough. It has become a spherical speck, the indubitable sign of the future Kermes. In a few days’ time it has dried up, despite the glass of water into which the base of the twig was immersed. Fortunately I have a few other similar corpuscles, a little more developed. My gleanings give me two kinds of corpuscle.
The more numerous are spherical in shape, their size varying according to their age. The smallest are rarely a millimetre[2] in diameter. The ventral surface is flat, and surrounded by a snowy cushion, the rough foundation of the waxy base. The dorsal surface is rounded, and in colour of a rusty red or pale chestnut with delicate white tufts distributed without any orderly arrangement. In this costume the young Kermes reminds us of a certain shell found in tropical seas: the striped or tiger cowry. The sugar refinery is already at work. At the back of the shell a limpid drop is gathering, to [[337]]which the Ants repair in order to quench their thirst. In a few weeks’ time the colour has changed to an ebony black, the sphere has attained the size of a pea and the Kermes has reached its final state.
The minority stretch themselves out in the likeness of a tiny half-contracted slug. The ventral surface is flat and its whole area is closely applied to the twig. The dorsal surface is convex, and its colour a more or less vivid amber yellow. It is sprinkled with protuberant specks of a snowy white, arranged in longitudinal rows to the number of five or seven. With its amber yellow colouration and its ornamentation of white specks, the tiny creature has something of the look of a certain kind of pastry which is sprinkled with spots of white sugar. There is no oozing of a syrupy liquid to the rear of the insect, so that the Ants do not visit it.
I have conjectured that this second form is the larval state of the males. From this, I imagine, will emerge winged insects ready for mating. To verify this guess of mine is impossible. My slug-like specimens die on their withering twig, and to follow their development beyond the walls of my study [[338]]would be an undertaking too great for my patience.
Of this very incomplete history of the Kermes of the oak-tree, one point especially should be remembered. The mother, an enormous ovary, exempt from the labours of egg-laying, contracts into a strong-box in which the family is hatched without the removal of the eggs. Within this shrivelled relic the family swarms in its thousands until the moment of exodus. Simplifying to the very extreme the usual method of procreation, the insect turns into a boxful of young.
FINIS
[[339]]
[1] Kermes in French, the word is pronounced Kurmees in English. The dried bodies of the female insect were long supposed to be galls or berries: they were even known to trade as “kermes berries,” and were sometimes used in medicine. It is allied to the cochineal insect, although the female of the latter is very obviously an insect, browsing on the juice of certain cactuses. The kermes is found on several kinds of oak, but principally on the kermes oak, a dwarf evergreen, Q. Coccifera.—Translator’s Note. [↑]