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.