INSECT ARCHITECTURE

LONDON: PRINTED BY W. CLOWES AND SONS, STAMFORD STREET AND CHARING CROSS.

INSECT ARCHITECTURE

BY

JAMES RENNIE

NEW EDITION, MUCH ENLARGED

BY THE REV. J. G. WOOD, M.A.

AUTHOR OF “HOMES WITHOUT HANDS,” ETC.

WITH NEARLY TWO HUNDRED ILLUSTRATIONS.

LONDON:
BELL AND DALDY, YORK STREET,
COVENT GARDEN.
1869.

[EDITOR’S PREFACE TO THE NEW EDITION.]

The proprietors of this interesting work having felt that much additional knowledge of the subject has been obtained since the book was written, have asked me to supply characteristic examples of Insect Architecture which were not to be found in its pages. I have accordingly added a considerable number of such examples, in most cases accompanied by figures drawn from the specimens described. I have not been at liberty to alter or expunge, and am not, therefore, responsible for any portion of the letterpress except those passages which are enclosed in brackets [ ]. Some of the specimens from which the figures have been drawn are in my own collection, but the greater part are to be found in the British Museum.

CONTENTS.

ILLUSTRATIONS.

INSECT ARCHITECTURE.

CHAPTER 1.

INTRODUCTION.

It can never be too strongly impressed upon a mind anxious for the acquisition of knowledge, that the commonest things by which we are surrounded are deserving of minute and careful attention. The most profound investigations of Philosophy are necessarily connected with the ordinary circumstances of our being, and of the world in which our every-day life is spent. With regard to our own existence, the pulsation of the heart, the act of respiration, the voluntary movement of our limbs, the condition of sleep, are among the most ordinary operations of our nature; and yet how long were the wisest of men struggling with dark and bewildering speculations before they could offer anything like a satisfactory solution of these phenomena, and how far are we still from an accurate and complete knowledge of them! The science of Meteorology, which attempts to explain to us the philosophy of matters constantly before our eyes, as dew, mist, and rain, is dependent for its illustrations upon a knowledge of the most complicated facts, such as the influence of heat and electricity upon the air; and this knowledge is at present so imperfect, that even these common occurrences of the weather, which men have been observing and reasoning upon for ages, are by no means satisfactorily explained, or reduced to the precision that every science should aspire to. Yet, however difficult it may be entirely to comprehend the phenomena we daily witness, everything in nature is full of instruction. Thus the humblest flower of the field, although, to one whose curiosity has not been excited, and whose understanding has, therefore, remained uninformed, it may appear worthless and contemptible, is valuable to the botanist, not only with regard to its place in the arrangement of this portion of the Creator’s works, but as it leads his mind forward to the consideration of those beautiful provisions for the support of vegetable life, which it is the part of the physiologist to study and to admire.

This train of reasoning is peculiarly applicable to the economy of insects. They constitute a very large and interesting part of the animal kingdom. They are everywhere about us. The spider weaves his curious web in our houses; the caterpillar constructs his silken cell in our gardens; the wasp that hovers over our food has a nest not far removed from us, which she has assisted to build with the nicest art; the beetle that crawls across our path is also an ingenious and laborious mechanic, and has some curious instincts to exhibit to those who will feel an interest in watching his movements; and the moth that eats into our clothes has something to plead for our pity, for he came, like us, naked into the world, and he has destroyed our garments, not in malice or wantonness, but that he may clothe himself with the same wool which we have stripped from the sheep. An observation of the habits of these little creatures is full of valuable lessons, which the abundance of the examples has no tendency to diminish. The more such observations are multiplied, the more are we led forward to the freshest and the most delightful parts of knowledge; the more do we learn to estimate rightly the extraordinary provisions and most abundant resources of a creative Providence; and the better do we appreciate our own relations with all the infinite varieties of nature, and our dependence, in common with the ephemeron that flutters its little hour in the summer sun, upon that Being in whose scheme of existence the humblest as well as the highest creature has its destined purposes. “If you speak of a stone,” says St. Basil, one of the Fathers of the Church, “if you speak of a fly, a gnat, or a bee, your conversation will be a sort of demonstration of His power whose hand formed them, for the wisdom of the workman is commonly perceived in that which is of little size. He who has stretched out the heavens, and dug up the bottom of the sea, is also He who has pierced a passage through the sting of the bee for the ejection of its poison.”

If it be granted that making discoveries is one of the most satisfactory of human pleasures, then we may without hesitation affirm, that the study of insects is one of the most delightful branches of natural history, for it affords peculiar facilities for its pursuit. These facilities are found in the almost inexhaustible variety which insects present to the curious observer. As a proof of the extraordinary number of insects within a limited field of observation, Mr. Stephens informs us, that in the short space of forty days, between the middle of June and the beginning of August, he found, in the vicinity of Ripley, specimens of above two thousand four hundred species of insects, exclusive of caterpillars and grubs,—a number amounting to nearly a fourth of the insects ascertained to be indigenous. He further tells us, that, among these specimens, although the ground had, in former seasons, been frequently explored, there were about one hundred species altogether new, and not before in any collection which he had inspected, including several new genera; while many insects reputed scarce were in considerable plenty.[A][A] The localities of insects are, to a certain extent, constantly changing; and thus the study of them has, in this circumstance, as well as in their manifold abundance, a source of perpetual variety. Insects, also, which are plentiful one year, frequently become scarce, or disappear altogether, the next—a fact strikingly illustrated by the uncommon abundance, in 1826 and 1827, of the seven-spot lady-bird (Coccinella septempunctata), in the vicinity of London, though during the two succeeding summers this insect was comparatively scarce, while the small two-spot lady-bird (Coccinella bipunctata) was plentiful.

There is, perhaps, no situation in which the lover of nature and the observer of animal life may not find opportunities for increasing his store of facts. It is told of a state prisoner, under a cruel and rigorous despotism, that when he was excluded from all commerce with mankind, and was shut out from books, he took an interest and found consolation in the visits of a spider; and there is no improbability in the story. The operations of that persecuted creature are among the most extraordinary exhibitions of mechanical ingenuity; and a daily watching of the workings of its instinct would beget admiration in a rightly-constituted mind. The poor prisoner had abundant leisure for the speculations in which the spider’s web would enchain his understanding. We have all of us, at one period or other of our lives, been struck with some singular evidence of contrivance in the economy of insects, which we have seen with our own eyes. Want of leisure, and probably want of knowledge, have prevented us from following up the curiosity which for a moment was excited. And yet some such accident has made men naturalists, in the highest meaning of the term. Bonnet, evidently speaking of himself, says, “I knew a naturalist, who, when he was seventeen years of age, having heard of the operations of the ant-lion, began by doubting them. He had no rest till he had examined into them: and he verified them, he admired them, he discovered new facts, and soon became the disciple and the friend of the Pliny of France”[B] (Réaumur). It is not the happy fortune of many to be able to devote themselves exclusively to the study of nature, unquestionably the most fascinating of human employments; but almost every one may acquire sufficient knowledge to be able to derive a high gratification from beholding the more common operations of animal life. His materials for contemplation are always before him. Some weeks ago we made an excursion to West Wood, near Shooter’s Hill, expressly for the purpose of observing the insects we might meet with in the wood: but we had not got far among the bushes, when heavy rain came on. We immediately sought shelter among the boughs of some thick underwood, composed of oak, birch, and aspen; but we could not meet with a single insect, not even a gnat or a fly, sheltered under the leaves. Upon looking more narrowly, however, into the bushes which protected us, we soon found a variety of interesting objects of study. The oak abounded in galls, several of them quite new to us; while the leaves of the birch and the aspen exhibited the curious serpentine paths of the minute mining caterpillars. When we had exhausted the narrow field of observation immediately around us, we found that we could considerably extend it, by breaking a few of the taller branches near us, and then examining their leaves at leisure. In this manner two hours glided quickly and pleasantly away, by which time the rain had nearly ceased; and though we had been disappointed in our wish to ramble through the wood, we did not return without adding a few interesting facts to our previous knowledge of insect economy.[C]

It will appear, then, from the preceding observations, that cabinets and collections, though undoubtedly of the highest use, are by no means indispensable, as the observer of nature may find inexhaustible subjects of study in every garden and in every hedge. Nature has been profuse enough in affording us materials for observation, when we are prepared to look about us with that keenness of inquiry, which curiosity, the first step in the pursuit of knowledge, will unquestionably give. Nor shall we be disappointed in the gratification which is thus within our reach. Were it no more, indeed, than a source of agreeable amusement, the study of insects comes strongly recommended to the notice of the well-educated. The pleasures of childhood are generally supposed to be more exquisite, and to contain less alloy, than those of riper years; and if so, it must be because then everything appears new and dressed in fresh beauties: while in manhood, and old age, whatever has frequently recurred begins to wear the tarnish of decay. The study of nature affords us a succession of “ever-new delights,” such as charmed us in childhood, when everything had the attractions of novelty and beauty; and thus the mind of the naturalist may have its own fresh and vigorous thoughts, even while the infirmities of age weigh down the body.

It has been objected to the study of insects, as well as to that of Natural History in general, that it tends to withdraw the mind from subjects of higher moment; that it cramps and narrows the range of thought; and that it destroys, or at least weakens, the finer creations of the fancy. Now, we should allow this objection in its fullest extent, and even be disposed to carry it further than is usually done, if the collecting of specimens only, or, as the French expressly call them, chips (échantillons), be called a study. But the mere collector is not, and cannot be, justly considered as a naturalist; and, taking the term naturalist in its enlarged sense, we can adduce some distinguished instances in opposition to the objection. Rousseau, for example, was passionately fond of the Linnæan botany, even to the driest minutiæ of its technicalities; and yet it does not appear to have cramped his mind, or impoverished his imagination. If Rousseau, however, be objected to as an eccentric being, from whose pursuits no fair inference can be drawn, we give the illustrious example of Charles James Fox, and may add the names of our distinguished poets, Goldsmith, Thomson, Gray, and Darwin, who were all enthusiastic naturalists. We wish particularly to insist upon the example of Gray, because he was very partial to the study of insects. It may be new to many of our readers, who are familiar with the ‘Elegy in a Country Churchyard,’ to be told that its author was at the pains to turn the characteristics of the Linnæan orders of insects into Latin hexameters, the manuscript of which is still preserved in his interleaved copy of the ‘Systema Naturæ.’ Further, to use the somewhat exaggerated words of Kirby and Spence, whose work on Entomology is one of the most instructive and pleasing books on the science, 'Aristotle among the Greeks, and Pliny the Elder among the Romans, may be denominated the fathers of Natural History, as well as the greatest philosophers of their day; yet both these made insects a principal object of their attention: and in more recent times, if we look abroad, what names greater than those of Redi, Malpighi, Vallisnieri, Swammerdam, Leeuwenhoek, Réaumur, Linnæus, De Geer, Bonnet, and the Hubers? and at home, what philosophers have done more honour to their country and to human nature than Ray, Willughby, Lister, and Derham? Yet all these made the study of insects one of their most favourite pursuits."[D]

And yet this study has been considered, by those who have superficially examined the subject, as belonging to a small order of minds; and the satire of Pope has been indiscriminately applied to all collectors, while, in truth, it only touches those who mistake the means of knowledge for the end:—

"O! would the sons of men once think their eyes
And reason given them but to study Flies!
See Nature, in some partial, narrow shape,
And let the Author of the whole escape;
Learn but to trifle; or, who most observe,
To wonder at their Maker, not to serve."[E]

Thus exclaims the Goddess of Dulness, sweeping into her net all those who study nature in detail. But if the matter were rightly appreciated, it would be evident that no part of the works of the Creator can be without the deepest interest to an inquiring mind; and that a portion of creation which exhibits such extraordinary manifestations of design as is shown by insects must have attractions for the very highest understanding.

An accurate knowledge of the properties of insects is of great importance to man, merely with relation to his own comfort and security. The injuries which they inflict upon us are extensive and complicated; and the remedies which we attempt, by the destruction of those creatures, both insects, birds, and quadrupeds, who keep the ravages in check, are generally aggravations of the evil, because they are directed by an ignorance of the economy of nature. The little knowledge which we have of the modes by which insects may be impeded in their destruction of much that is valuable to us, has probably proceeded from our contempt of their individual insignificance. The security of property has ceased to be endangered by quadrupeds of prey, and yet our gardens are ravaged by aphides and caterpillars. It is somewhat startling to affirm that the condition of the human race is seriously injured by these petty annoyances; but it is perfectly true that the art and industry of man have not yet been able to overcome the collective force, the individual perseverance, and the complicated machinery of destruction which insects employ. A small ant, according to a most careful and philosophical observer, opposes almost invincible obstacles to the progress of civilization in many parts of the equinoctial zone. These animals devour paper and parchment; they destroy every book and manuscript. Many provinces of Spanish America cannot, in consequence, show a written document of a hundred years’ existence. “What development,” he adds, “can the civilization of a people assume, if there be nothing to connect the present with the past—if the depositories of human knowledge must be constantly renewed—if the monuments of genius and wisdom cannot be transmitted to posterity?”[F] Again, there are beetles which deposit their larvæ in trees in such formidable numbers that whole forests perish beyond the power of remedy. The pines of the Hartz have thus been destroyed to an enormous extent; and in North America, at one place in South Carolina, at least ninety trees in every hundred, upon a tract of two thousand acres, were swept away by a small black, winged bug. And yet, according to Wilson, the historian of American birds, the people of the United States were in the habit of destroying the redheaded woodpecker, the great enemy of these insects, because he occasionally spoilt an apple.[G] The same delightful writer and true naturalist, speaking of the labours of the ivory-billed woodpecker, says, “Would it be believed that the larvæ of an insect or fly, no larger than a grain of rice, should silently, and in one season, destroy some thousand acres of pine-trees, many of them from two to three feet in diameter, and a hundred and fifty feet high? In some places the whole woods, as far as you can see around you, are dead, stripped of the bark, their wintry-looking arms and bare trunks bleaching in the sun, and tumbling in ruins before every blast.”[H] The subterraneous larva of some species of beetle has often caused a complete failure of the seed-corn, as in the district of Halle in 1812.[I] The corn-weevil, which extracts the flour from grain, leaving the husk behind, will destroy the contents of the largest storehouses in a very short period. The wire-worm and the turnip-fly are dreaded by every farmer. The ravages of the locust are too well known not to be at once recollected as an example of the formidable collective power of the insect race. The white ants of tropical countries sweep away whole villages with as much certainty as a fire or an inundation; and ships even have been destroyed by these indefatigable republics. Our own docks and embankments have been threatened by such minute ravagers.

The enormous injuries which insects cause to man may thus be held as one reason for ceasing to consider the study of them as an insignificant pursuit; for a knowledge of their structure, their food, their enemies, and their general habits, may lead, as it often has led, to the means of guarding against their injuries. At the same time we derive from them both direct and indirect benefits. The honey of the bee, the dye of the cochineal, and the web of the silk-worm, the advantages of which are obvious, may well be balanced against the destructive propensities of insects which are offensive to man. But a philosophical study of natural history will teach us that the direct benefits which insects confer upon us are even less important than their general uses in maintaining the economy of the world. The mischiefs which result to us from the rapid increase and the activity of insects are merely results of the very principle by which they confer upon us numberless indirect advantages. Forests are swept away by minute beetles; but the same agencies relieve us from that extreme abundance of vegetable matter which would render the earth uninhabitable were this excess not periodically destroyed. In hot countries the great business of removing corrupt animal matter, which the vulture and hyæna imperfectly perform, is effected with certainty and speed by the myriads of insects that spring from the eggs deposited in every carcase by some fly seeking therein the means of life for her progeny. Destruction and reproduction, the great laws of nature, are carried on very greatly through the instrumentality of insects; and the same principle regulates even the increase of particular species of insects themselves. When aphides are so abundant that we know not how to escape their ravages, flocks of lady-birds instantly cover our fields and gardens to destroy them. Such considerations as these are thrown out to show that the subject of insects has a great philosophical importance—and what portion of the works of nature has not? The habits of all God’s creatures, whether they are noxious, or harmless, or beneficial, are worthy objects of our study. If they affect ourselves, in our health or our possessions, whether for good or for evil, an additional impulse is naturally given to our desire to attain a knowledge of their properties. Such studies form one of the most interesting occupations which can engage a rational and inquisitive mind; and, perhaps, none of the employments of human life are more dignified than the investigation and survey of the workings and the ways of nature in the minutest of her productions.

The exercise of that habit of observation which can alone make a naturalist—“an out-of-door naturalist,” as Daines Barrington calls himself—is well calculated to strengthen even the most practical and merely useful powers of the mind. One of the most valuable mental acquirements is the power of discriminating among things which differ in many minute points, but whose general similarity of appearance usually deceives the common observer into a belief of their identity. The study of insects, in this point of view, is most peculiarly adapted for youth. According to our experience, it is exceedingly difficult for persons arrived at manhood to acquire this power of discrimination; but, in early life, a little care on the part of the parent or teacher will render it comparatively easy. In this study the knowledge of things should go along with that of words. “If names perish,” says Linnæus, “the knowledge of things perishes also:”[J] and, without names, how can any one communicate to another the knowledge he has acquired relative to any particular fact, either of physiology, habit, utility, or locality? On the other hand, mere catalogue learning is as much to be rejected as the loose generalizations of the despisers of classification and nomenclature. To name a plant, or an insect, or a bird, or a quadruped rightly, is one step towards an accurate knowledge of it; but it is not the knowledge itself. It is the means, and not the end in natural history, as in every other science.

If the bias of opening curiosity be properly directed, there is not any branch of natural history so fascinating to youth as the study of insects. It is, indeed, a common practice in many families to teach children, from their earliest infancy, to treat the greater number of insects as if they were venomous and dangerous, and, of course, meriting to be destroyed, or at least avoided with horror. Associations are by this means linked with the very appearance of insects, which become gradually more inveterate with advancing years; provided, as most frequently happens, the same system be persisted in, of avoiding or destroying almost every insect which is unlucky enough to attract observation. How much rational amusement and innocent pleasure is thus thoughtlessly lost; and how many disagreeable feelings are thus created, in the most absurd manner! In order to show that the study or (if the word be disliked) the observation of insects is peculiarly fascinating to children, even in their early infancy, we may refer to what we have seen in the family of a friend, who is partial to this, as well as to all the departments of natural history. Our friend’s children, a boy and girl, were taught, from the moment they could distinguish insects, to treat them as objects of interest and curiosity, and not to be afraid even of those which wore the most repulsive appearance. The little girl, for example, when just beginning to walk alone, encountered one day a large staphylinus (Goërius olens? Stephens; vulgo, the devil’s coach-horse), which she fearlessly seized, and did not quit her hold, though the insect grasped one of her fingers in his formidable jaws. The mother, who was by, knew enough of the insect to be rather alarmed for the consequences, though she prudently concealed her feelings from the child. She did well; for the insect was not strong enough to break the skin, and the child took no notice of its attempts to bite her finger. A whole series of disagreeable associations with this formidable-looking family of insects was thus averted at the very moment when a different mode of acting on the part of the mother would have produced the contrary effect. For more than two years after this occurrence the little girl and her brother assisted in adding numerous specimens to their father’s collection, without the parents ever having cause, from any accident, to repent of their employing themselves in this manner. The sequel of the little girl’s history strikingly illustrates the position for which we contend. The child happened to be sent to a relative in the country, where she was not long in having carefully instilled into her mind all the usual antipathies against “everything that creepeth on the earth;” and though she afterwards returned to her paternal home, no persuasion or remonstrance could ever again persuade her to touch a common beetle, much less a staphylinus, with its tail turned up in a threatening attitude, and its formidable jaws ready extended for attack or defence.[K] We do not wish that children should be encouraged to expose themselves to danger in their encounters with insects. They should be taught to avoid those few which are really noxious—to admire all—to injure none.

The various beauty of insects—their glittering colours, their graceful forms—supplies an inexhaustible source of attraction. Even the most formidable insects, both in appearance and reality,—the dragon-fly, which is perfectly harmless to man, and the wasp, whose sting every human being almost instinctively shuns,—are splendid in their appearance, and are painted with all the brilliancy of natural hues. It has been remarked that the plumage of tropical birds is not superior in vivid colouring to what may be observed in the greater number of butterflies and moths.[L] “See,” exclaims Linnæus, “the large, elegant painted wings of the butterfly, four in number, covered with delicate feathery scales! With these it sustains itself in the air a whole day, rivalling the flight of birds and the brilliancy of the peacock. Consider this insect through the wonderful progress of its life,—how different is the first period of its being from the second, and both from the parent insect! Its changes are an inexplicable enigma to us: we see a green caterpillar, furnished with sixteen feet, feeding upon the leaves of a plant; this is changed into a chrysalis, smooth, of golden lustre, hanging suspended to a fixed point, without feet, and subsisting without food; this insect again undergoes another transformation, acquires wings, and six feet, and becomes a gay butterfly, sporting in the air, and living by suction upon the honey of plants. What has nature produced more worthy of our admiration than such an animal, coming upon the stage of the world, and playing its part there under so many different masks?” The ancients were so struck with the transformations of the butterfly, and its revival from a seeming temporary death, as to have considered it an emblem of the soul, the Greek word pysche signifying both the soul and a butterfly; and it is for this reason that we find the butterfly introduced into their allegorical sculptures as an emblem of immortality. Trifling, therefore, and perhaps contemptible, as to the unthinking may seem the study of a butterfly, yet when we consider the art and mechanism displayed in so minute a structure,—the fluids circulating in vessels so small as almost to escape the sight—the beauty of the wings and covering—and the manner in which each part is adapted for its peculiar functions,—we cannot but be struck with wonder and admiration, and allow, with Paley, that “the production of beauty was as much in the Creator’s mind in painting a butterfly as in giving symmetry to the human form.”

A collection of insects is to the true naturalist what a collection of medals is to the accurate student of history. The mere collector, who looks only to the shining wings of the one, or the green rust of the other, derives little knowledge from his pursuit. But the cabinet of the naturalist becomes rich in the most interesting subjects of contemplation, when he regards it in the genuine spirit of scientific inquiry. What, for instance, can be so delightful as to examine the wonderful variety of structure in this portion of the creation; and, above all, to trace the beautiful gradations by which one species runs into another? Their differences are so minute, that an unpractised eye would proclaim their identity; and yet, when the species are separated, and not very distantly, they become visible even to the common observer. It is in examinations such as these that the naturalist finds a delight of the highest order. While it is thus one of the legitimate objects of his study to attend to minute differences of structure, form, and colouring, he is not less interested in the investigation of habits and economy; and in this respect the insect world is inexhaustibly rich. We find herein examples of instinct to parallel those of all the larger animals, whether they are solitary or social; and innumerable others besides, altogether unlike those manifested in the superior departments of animated nature. These instincts have various directions, and are developed in a more or less striking manner to our senses, according to the force of the motive by which they are governed. Some of their instincts have for their object the preservation of insects from external attack; some have reference to procuring food, and involve many remarkable stratagems; some direct their social economy, and regulate the condition under which they live together either in monarchies or republics, their colonizations, and their migrations; but the most powerful instinct which belongs to insects has regard to the preservation of their species. We find, accordingly, that as the necessity for this preservation is of the utmost importance in the economy of nature, so for this especial object many insects, whose offspring, whether in the egg or the larva state, are peculiarly exposed to danger, are endued with an almost miraculous foresight, and with an ingenuity, perseverance, and unconquerable industry, for the purpose of avoiding those dangers, which are not to be paralleled even by the most singular efforts of human contrivance. The same ingenuity which is employed for protecting either eggs, or caterpillars and grubs, or pupæ and chrysalides, is also exercised by many insects for their own preservation against the changes of temperature to which they are exposed, or against their natural enemies. Many species employ those contrivances during the period of their hibernation, or winter sleep. For all these purposes some dig holes in the earth, and form them into cells; others build nests of extraneous substances, such as bits of wood and leaves; others roll up leaves into cases, which they close with the most curious art; others build a house of mud, and line it with the cotton of trees, or the petals of the most delicate flowers; others construct cells, of secretions from their own bodies; others form cocoons, in which they undergo their transformation; and others dig subterraneous galleries, which, in their complexity of arrangement, in solidity, and in complete adaptation to their purposes, vie with the cities of civilised man. The contrivances by which insects effect these objects have been accurately observed and minutely described, by patient and philosophical inquirers, who knew that such employments of the instinct with which each species is endowed by its Creator offered the most valuable and instructive lessons, and opened to them a wide field of the most delightful study. The construction of their habitations is certainly among the most remarkable peculiarities in the economy of insects; and it is of this subject that we propose to treat under the general name, which is sufficiently applicable to our purpose, of Insect Architecture.

In the descriptions which we shall give of Insect Architecture, we shall employ as few technical words as possible: and such as we cannot well avoid, we shall explain in their places; but, since our subject chiefly relates to the reproduction of insects, it may be useful to many readers to introduce here a brief description of the changes which they undergo.

Magnified eggs, of a, Geometra armillata; b, of an unknown water insect; c, of the lacquey moth; d, of a caddis-fly (Phryganea atrata); e, of red under-wing moth (Catocala nupta); f, of Pontia Brassicæ; g, of the Clifden Nonpareil moth.

It was of old believed that insects were produced spontaneously by putrefying substances; and Virgil gives the details of a process for creating a swarm of bees out of the carcase of a bull; but Redi, a celebrated Italian naturalist, proved by rigid experiments that they are always, in such cases, hatched from eggs previously laid. Most insects, indeed, lay eggs, though some few are viviparous, and some propagate both ways. The eggs of insects are very various in form, and seldom shaped like those of birds. We have here figured those of several species, as they appear under the microscope.

When an insect first issues from the egg, it is called by naturalists larva, and, popularly, a caterpillar, a grub, or a maggot. The distinction, in popular language, seems to be, that caterpillars are produced from the eggs of moths or butterflies; grubs from the eggs of beetles, bees, wasps, &c.; and maggots (which are without feet) from blow-flies, house-flies, cheese-flies, &c., though this is not very rigidly adhered to in common parlance. Maggots are also sometimes called worms, as in the instance of the meal-worm; but the common earth-worm is not a larva, nor is it by modern naturalists ranked among insects.

a, Ametabolous pupa of Cicada; b, caterpillar of tussock moth (Laria fascelina); c, larva of the poplar beetle (Chrysomela populi); d, larva of Sinex; e, larva of the common gnat.

There are, however, certain larvæ, as those of the Cicada, the crickets, the water-boatman (Notonecta), the cockroach, &c., which resemble the perfect insects in form, excepting that they are destitute of wings; but in the pupa state these appear in a rudimentary condition, at least in such species as have wings in the mature stage of existence. The pupæ are active and eat. Insects, the larvæ and pupæ of which are so similar to the adults, are termed Ametabolous (a, without, [Greek: metabolê], change); those the larvæ of which undergo changes of a marked character, Metabolous (Insecta ametabola and Insecta metabola, Burmeister).

Larvæ are remarkably small at first, but grow rapidly. The full-grown caterpillar of the goat-moth (Cossus ligniperda) is thus seventy-two thousand times heavier than when it issues from the egg; and the maggot of the blow-fly is, in twenty-four hours, one hundred and fifty-five times heavier than at its birth. Some larvæ have feet, others are without; none have wings. They cannot propagate. They feed voraciously on coarse substances; and as they increase in size, which they do very rapidly, they cast their skins three or four times. In defending themselves from injury, and in preparing for their change by the construction of secure abodes, they manifest great ingenuity and mechanical skill. The figures on the preceding page exemplify various forms of insects in this stage of their existence.

a, Pupa of a Water-Beetle (Hydrophilus); b, pupa of Sphinx Ligustri.

When larvæ are full grown, they cast their skins for the last time, undergo a complete change of form, excepting in the case of ametabolous larvæ, cease to eat, and remain nearly motionless. The inner skin of the larva now becomes converted into a membranous or leathery covering, which wraps the insect closely up like a mummy: in this condition it is termed Pupa, from its resemblance to an infant in swaddling bands. Nympha, or nymph, is another term given to insects in this stage;[M] moreover from the pupæ of many of the butterflies appearing gilt as if with gold, the Greeks called them Chrysalides, and the Romans Aureliæ, and hence naturalists frequently call a pupa chrysalis, even when it is not gilt. We shall see, as we proceed, the curious contrivances resorted to for protecting insects in this helpless state. The following are examples of insects in the imago, or perfect state.

Insects in the Imago or perfect state.
a, Nemopteryx coa, Leach.—b, Myrmeleon formicalynx, Fabricius.—c, Hesperia comma, Fabricius.—d, Nepa cinerea, Linnæus.

After a certain time, the insect which has remained in its pupa-case, like a mass of jelly without shape, is gradually preparing for its final change, when it takes the form of a perfect insect. This state was called by Linnæus Imago, because the insect, having thrown off its mask, becomes a perfect image of its species. Of some, this last portion of their existence is very short, others live through a year, and some exist for longer periods. They feed lightly, and never increase in size. The chief object of all is to perpetuate their species, after which the greater number quickly die. It is in this state that they exercise those remarkable instincts for the preservation of their race, which are exhibited in their preparations for the shelter of their eggs, and the nourishment of their larvæ.

[CHAPTER II.]

STRUCTURES FOR PROTECTING EGGS.—MASON-WASPS; MASON-BEES; MINING-BEES.

The provisions which are made by the different species of insects for protecting their eggs, appear in many cases to be admirably proportioned to the kind of danger and destruction to which they may be exposed. The eggs themselves, indeed, are not so liable to depredation and injury as the young brood hatched from them; for, like the seeds of plants, they are capable of withstanding greater degrees both of heat and cold than the insects which produce them. According to the experiments of Spallanzani, the eggs of frogs that had been exposed to various degrees of artificial heat were scarcely altered in their productive powers by a temperature of 111° of Fahrenheit, but they became corrupted after 133°. He tried the same experiment upon tadpoles and frogs, and found they all died at 111°. Silkworms died at a temperature of 108°, while their eggs did not entirely cease to be fertile till 144°. The larvæ of flesh-flies perished, while the eggs of the same species continued fertile, at about the same comparative degrees of heat as in the preceding instances. Intense cold has a still less effect upon eggs than extreme heat. Spallanzani exposed the eggs of silk-worms to an artificial cold 23° below zero, and yet, in the subsequent spring, they all produced caterpillars. Insects almost invariably die at the temperature of 14°, that is, at 18° below the freezing point.[N] The care of insects for the protection of their eggs is not entirely directed to their preservation in the most favourable temperature for being hatched, but to secure them against the numerous enemies which would attempt their destruction; and, above all, to protect the grubs, when they are first developed, from those injuries to which they are peculiarly exposed. Their prospective contrivances for accomplishing these objects are in the highest degree curious.

Most persons have more or less acquaintance with the hives of the social species of bees and wasps; but little is generally known of the nests constructed by the solitary species, though in many respects these are not inferior to the others in displays of ingenuity and skill. We admire the social bees, labouring together for one common end, in the same way that we look with delight upon the great division of labour in a well-ordered manufactory. As in a cotton-mill some attend to the carding of the raw material, some to its formation into single threads, some to the gathering these threads upon spindles, others to the union of many threads into one,—all labouring with invariable precision because they attend to a single object;—so do we view with delight and wonder the successive steps by which the hive-bees bring their beautiful work to its completion,—striving, by individual efforts, to accomplish their general task, never impeding each other by useless assistance, each taking a particular department, and each knowing its own duties. We may, however, not the less admire the solitary wasp or bee, who begins and finishes every part of its destined work; just as we admire the ingenious mechanic who perfects something useful or ornamental entirely by the labour of his own hands,—whether he be the patient Chinese carver, who cuts the most elaborately-decorated boxes out of a solid piece of ivory, or the turner of Europe, who produces every variety of elegant form by the skilful application of the simplest means.

Our island abounds with many varieties of solitary wasps and bees; and their nests may therefore be easily discovered by those who, in the proper seasons, are desirous of observing the peculiarities of their architecture.

Odynerus.—Natural size.

Mason-Wasps.

In September, 1828, a common species of solitary mason-wasp (Odynerus, Latr.) was observed by us (J. R.) on the east wall of a house at Lee, in Kent, very busy in excavating a hole in one of the bricks, about five feet from the ground. Whether there might not have been an accidental hole in the brick before the wasp commenced her labours, is unknown, as she had made considerable progress in the work when first observed: but the brick was one of the hardest of the yellow sort made in this neighbourhood. The most remarkable circumstance in the process of hewing into the brick was the care of the insect in removing to a distance the fragments which from time to time she succeeded in detaching. It did not appear to suit her design to wear down the brick, particle by particle, as the furniture beetle (Anobium pertinax) does in making its pin-hole galleries in old wood. Our wasp-architect, on the contrary, by means of her strong tranchant-toothed jaws, severed a piece usually about the bigness of a mustard-seed. It might have been supposed that these fragments would have been tossed out of the hole as the work proceeded, without further concern; as the mole tosses above ground the earth which has been cleared out of its subterranean gallery. The wasp was of a different opinion; for it was possible that a heap of brick chips, at the bottom of the wall, might lead to the discovery of her nest by some of her enemies, particularly by one or other of the numerous tribe of what are called ichneumon-flies. This name is given to them, from the similarity of their habit of destroying eggs, to that of the little animal which proves so formidable an enemy to the multiplication of the crocodile of Egypt. They may be also denominated cuckoo-flies, because, like that bird, they thrust their egg into the nest of another species. These flies are continually prowling about and prying into every corner, to find, by stealth, a nidus for their eggs. It might have been some such consideration as this which induced the wasp to carry off the fragments as they were successively detached. That concealment was the motive, indeed, was proved: for one of the fragments which fell out of the hole by accident, she immediately sought for at the bottom of the wall, and carried off like the rest. It was no easy matter to get out one of the fragments, as may readily be conceived when the size of the insect is compared with that of the entrance of which this (

) is the exact size, as taken from the impression of a bit of dough upon the hole when finished. It was only by seizing the fragment with her jaws, and retreating backwards, that the matter could be accomplished; though, after the interior of the excavation was barely large enough to admit of her turning round, she more than once attempted to make her exit head-foremost, but always unsuccessfully. The weight of the fragments removed did not appear to impede her flight, and she generally returned to her task in about two or three minutes.

Mandibles—Jaws of Mason-Wasp.—Greatly magnified.

Within two days the excavation was completed; but it required two other days to line it with a coating of clay, to deposit the eggs, two in number, and, no doubt, to imprison a few live spiders or caterpillars for the young when hatched—a process which was first observed by Ray and Willughby,[O] but which has since been frequently ascertained. In the present instance, this peculiarity was not seen; but the little architect was detected in closing up the entrance, which was formed of a layer of clay more than double the thickness of the interior lining. In November following, we hewed away the brick around this nest, and found the whole excavation was rather less than an inch in depth.

Cuckoo-Fly
(Tachina larvarum?).—Natural size.

Notwithstanding all the precautions of the careful parent to conceal her nest it was found out by one of the cuckoo-flies (Tachina larvarum?)—probably a common species very similar to the house-fly, but rather larger, which deposited an egg there; and the grub hatched from it, after devouring one of the wasp-grubs, formed itself a cocoon (a), as did the other undevoured grub of the wasp (b). Both awaited the return of summer to change into winged insects, burst their cerements, and proceed as their parents did.

Mason-Wasp’s Nest and Cocoons.—About one-third the natural size.

Mason-Wasp (Odynerus murarius).—Natural size.

Another mason-wasp (Odynerus murarius, Latr.), differing little in appearance from the former, may often be seen frequenting sandy banks exposed to the sun, and constructing its singular burrows. The sort of sand-bank which it selects is hard and compact; and though this may be more difficult to penetrate, the walls are not liable to fall down upon the little miner. In such a bank, the mason-wasp bores a tubular gallery two or three inches deep. The sand upon which Réaumur found some of these wasps at work was almost as hard as stone, and yielded with difficulty to his nail; but the wasps dug into it with ease, having recourse, as he ascertained, to the ingenious device of moistening it by letting fall two or three drops of fluid from their mouth, which rendered the mass ductile, and the separation of the grains easy to the double pickaxe of the little pioneers.

Nests, &c., of Mason-Wasps.—About half the natural size.
a, The tower of the nest; b, the entrance after the tower is removed; c, the cell; d, the cell, with a roll of caterpillars prepared for the larva.

When this wasp has detached a few grains of the moistened sand, it kneads them together into a pellet about the size of one of the seeds of a gooseberry. With the first pellet which it detaches, it lays the foundation of a round tower, as an outwork, immediately over the mouth of its nest. Every pellet which it afterwards carries off from the interior is added to the wall of this outer round tower, which advances in height as the hole in the sand increases in depth. Every two or three minutes, however, during these operations, it takes a short excursion, for the purpose, probably, of replenishing its store of fluid wherewith to moisten the sand. Yet so little time is lost, that Réaumur has seen a mason-wasp dig in an hour a hole the length of its body, and at the same time build as much of its round tower. For the greater part of its height this round tower is perpendicular; but towards the summit it bends into a curve, corresponding to the bend of the insect’s body, which in all cases of insect architecture, is the model followed. The pellets which form the walls of the tower are not very nicely joined, and numerous vacuities are left between them, giving it the appearance of filigree-work. That it should be thus slightly built is not surprising, for it is intended as a temporary structure for protecting the insect while it is excavating its hole, and as a pile of materials, well arranged and ready at hand, for the completion of the interior building,—in the same way that workmen make a regular pile of bricks near the spot where they are going to build. This seems, in fact, to be the main design of the tower, which is taken down as expeditiously as it had been reared. Réaumur thinks that, by piling in the sand which has previously been dug out, the wasp intends to guard her progeny for a time from being exposed to the too violent heat of the sun; and he has even sometimes seen that there were not sufficient materials in the tower, in which case the wasp had recourse to the rubbish she had thrown out after the tower was completed. By raising a tower of the materials which she excavates, the wasp produces the same shelter from external heat as a human creature would who chose to inhabit a deep cellar of a high house. She further protects her progeny from the ichneumon-fly, as the engineer constructs an outwork to render more difficult the approach of an enemy to the citadel. Réaumur has seen this indefatigable enemy of the wasp peep into the mouth of the tower, and then retreat, apparently frightened at the depth of the cell which he was anxious to invade.

The mason-wasp does not furnish the cell she has thus constructed with pollen and honey, like the solitary bees, but with living caterpillars, and these always of the same species—being of a green colour, and without feet. She fixes the caterpillars together in a spiral column: they cannot alter their position, although they remain alive. They are an easy prey to their smaller enemy; and when the grub has eaten them all up, it spins a case, and is transformed into a pupa, which afterwards becomes a wasp. The number of caterpillars which is thus found in the lower cavity of the mason-wasp’s nest is ordinarily from ten to twelve. The mother is careful to lay in the exact quantity of provision which is necessary to the growth of the grub before he quits his retreat. He works through his store till his increase in this state is perfected, and he is on the point of undergoing a change into another state, in which he requires no food. The careful purveyor, cruel indeed in her choice of a supply, but not the less directed by an unerring instinct, selects such caterpillars as she is conscious have completed their growth, and will remain thus imprisoned without increase or corruption till their destroyer has gradually satisfied the necessities of his being. “All that the worm of the wasp,” says Réaumur, “has to do in his nest, from his birth to his transformation, is to eat.” There is another species of wasp which does not at once enclose in its nest all the sustenance which its larva will require before transformation, but which from time to time imprisons a living caterpillar, and when that is consumed, opens the nest and introduces another.

[The upper figure in the accompanying illustration exhibits two of the curious towers built by this interesting insect and drawn of their natural size.]

The insect is one of the most plentiful in England, and can be found on sunny days, flitting about sand-banks and making its curious habitations. The length is nearly half an inch, and the colour is black, variegated with five yellow bands upon the abdomen.

The lower figure represents the habitations of one of the British solitary wasps, Pompilus punctum, and is given in order to show a curious resemblance in the structure. The specimen from which the sketch was taken was found under the eaves of a roof which protected a bee-hive. The cells were thirteen in number, very carefully constructed of earth, and several of them were closed. Although these cells were not fossorial in their nature, several other species of the same genus are as accomplished burrowers as any insect. Pompilus plumbeus, for example, another black species, burrows into sand, and is very plentiful on our more southern shores. It may usually be found hovering about sand-banks, and flitting about with such agility that it is by no means an easy insect to catch. The male is peculiarly apt to evade the stroke of the entomologist’s net.

Then there is Pompilus rufipes, which is a black insect, but distinguished by the conspicuous red colour of the hind legs. This is very fond of our coasts, and may be found wherever the soil is suitable for its excavations. Many species of this genus carry off spiders for the purpose of provisioning their nests. Several species, which live far inland, prefer light and dry earth to sand, and make therein their burrows, preferring our little white spider as the provision for their young. Although the same insect may be often observed to carry the same kind of prey to its home, it does not at all follow that no change is ever made.

But the most remarkable example of this fact may be found in a very common swift-winged insect, black in colour, with a reddish patch on the end of the abdomen. Its name is Trachytes pompiliformis, and it generally stocks its nest with small caterpillars. Mr. F. Smith, however, has taken it when in the act of carrying off a small species of grasshopper—certainly the very last insect that would be thought of as likely to be immured by a captor which must be scarcely larger than itself.

This insect is to be found in most warm and sandy situations, and may be looked for at the end of summer and beginning of autumn. It may be easily known by its red spot on the abdomen, and the large, transverse head; it is wider than the thorax.

One species of mining-bee, not often found in England, chooses some very singular insects wherewith to feed its young. Its name is Philanthus triangulum, and it is a very fierce, waspish-looking creature, with a large wide head, wider even than the thorax, sharp and powerful jaws, and with broad wings. The head and thighs are black, with a few spots of a yellowish white, and the abdomen is yellow, with a black spot in the middle of each segment. Its length rather exceeds half an inch. The actions of this insect do not belie its looks, for it is a fierce and active creature, seizing upon various bees and dragging them into its tunnel.

Mr. F. Smith discovered the metropolis of this usually scarce insect at Sandown Bay, in the Isle of Wight, and has given an interesting description of its habits. He states that although it is so ferocious towards other insects, it appears to be perfectly harmless as far as man is concerned, allowing itself to be handled without even attempting to use its sting. Indeed, he was quite unable to provoke the insect to do so. Various bees were captured by the Philanthus, and the favourites seemed to belong to the genus Andrena, itself a burrowing bee, and the common hive-bee. The Philanthus seemed perfectly indifferent whether they attacked the comparatively small and feeble Andrena, or the formidable hive-bee, taking them as they came, and caring nothing for the sting. The Philanthus that burrowed on the top of the cliff, seemed to prefer the hive-bee, because the red clover attracted greater numbers of that insect. Those that made their burrows at the top of the cliff, took the Andrenæ. Of course, the Philanthus is obliged to catch more of the Andrenæ than the hive bees. Only one species of this genus is known in England; it is to be found in July and August.

There is a very large genus of rather small humming-bees, many of which are popularly mistaken for wasps, on account of their sharply pointed and yellow banded abdomen; they belong to the genus Crabro, and are extremely variable in the material into which they burrow, and the insects with which they feed their young. Some species burrow into dry bramble sticks. If the reader should wish to obtain specimens of them, as well as other burrowers, he will find bramble, rose, and jessamine sticks most prolific in them. The best plan is to collect a quantity of these sticks and put them into glass tubes, with the ends stopped with wire gauze; there is then an absolute certainty of identifying the insect with its habitation. The spring is the best time for collecting. Sometimes these creatures are afflicted with parasites, which also are detained in the tube, so as to yield valuable information to the captor.

Some species burrow in sand-banks and feed their young with gnats, others burrow into dead timber, and stock their tunnels with flies of various kinds. One very useful species, Crabro lævis, burrows in sand-banks, and provisions its nest with the noxious turnip-fleas (Halticæ), great numbers of which are needed to stock a single burrow. It is rather a social insect, many burrows being often found near each other. The turnip-flea has so hard a shell, that the young Crabro seems hardly capable of eating it. Mr. Smith, however, has remarked that another burrowing-bee stocks its nest with certain weevils that are almost too hard to be pierced with a pin, and that the shell is probably softened by the damp ground. The greater number of this group, however, are burrowers into the ground, and stock their nests with flies of some kind.

Another species of this large genus, Crabro luteipalpis, is fond of making its burrows in the mortar of old walls, preferring those spots where nails have been drawn, making the process of burrowing easier for the insect. It is not uncommon in the outskirts of London. All gardeners, especially those who cultivate roses, ought to encourage this very little insect, and welcome its presence, for it provisions its nest with the aphides, or green blight, which infect the rose-trees, and which have destroyed so many promising plants.

The female, which is the larger of the two sexes, measures only three lines in length. The colour is shining black, and the head is rather squared.

Among other burrowing species of this genus we may mention Crabro varius, a rather long and slender insect, black in colour, with yellow spottings about the thorax. It prefers very hard fine sand, such as is found in partially excavated sand-banks, and provisions its burrows with gnats. It is tolerably plentiful.

Our last example of the earth-burrowers belonging to this genus is Crabro Wesmoeli, which chooses similar localities, being mostly found in sand-banks. It carries off flies of different kinds for the food of its young. There is a very common insect, closely allied to the last mentioned genus, whose horns are worthy of notice. This is called Typoxylon figulus. It is a small creature, with a large head and slender abdomen. Its colour is black, and on the edges of the segments of the abdomen there is a little silvery shining down.

It generally burrows into light earth, though it sometimes drives its tunnel into decayed wood. In either case, it provisions its nest with spiders, flying into the hedges, pulling the unfortunate spiders out of their webs, and carrying them into the burrow. One burrow contains a series of cells, which are separated from each other by partitions of sand, the particles of which are firmly cemented together by some glutinous substance secreted by the insect. Some species of this genus burrow into the pith of the bramble and other shrubs.

One of the most determined of our British burrowers is the insect which is known by the name of Ammophila sabulosa. It has a large, squared head, wider than the thorax, a very long and slender body, and short though powerful wings. The colour is black, with a slight rust-red tint on the base of the abdomen.

When the female has dug her burrow, she sets off in search of a caterpillar of proportionate size, and having conveyed it into her dwelling, she affixes an egg to the imprisoned larva, and goes off in search of another, carefully stopping up the entrance with stones. In fine weather she will fill one burrow with caterpillars in a few hours, and then begin another nursery for the future young. This species appears always to make use of caterpillars, but another allied species prefers spiders. Mr. F. Smith mentions that he has found in a high sand-bank as many as twenty females apparently hibernating together till suitable weather enabled them to pursue their usual economy.

There really seems to be scarcely any genus of insect that is not seized upon by one or other of these burrowers, and packed away in a half living state to form food for their young. There is one of these solitary burrowing wasps called the Astata boops, deriving its specific name from its large round eyes, which in the male completely unite at the back of the head. The abdomen is shaped something like a boy’s peg-top, or a symmetrical turnip, the peg of the top, or the point of the turnip, corresponding to the top of the abdomen. Its length is about half an inch, and its colour is black, with a rust-red patch on the end of the abdomen.

There is a remarkably pretty, and very variable, sand-wasp, which is plentiful in most parts of the country. The colour is black, and the abdomen is banded by four yellow bars. Its feet are also yellow. Mr. Smith has written a very interesting account of the proceedings of this insect.

"Having frequently observed the habits of the type of this genus, Mellinus arvensis, and reared it from the larva state, a few observations are here recorded. When the parent insect has formed a burrow of the required length, and enlarged the extremity into a chamber of proper dimensions, she issues forth in search of the proper nutriment for her young; this consists of various dipterous insects: species of various genera are equally adapted to her purpose—Muscidæ, Syrphidæ, &c., are captured.

"It is amusing to see four or five females lie in wait upon a patch of cow-dung until some luckless fly settles on it. When this happens, a cunning and gradual approach is made; a sudden attempt would not succeed. The fly is the insect of quickest flight, therefore a degree of intrigue is necessary. This is managed by running past the victim slowly, and apparently in an unconcerned manner, until the poor fly is caught unawares, and carried off by the Mellinus to its burrow. The first fly being deposited, an egg is laid. The necessary number of flies are soon secured, and her task is completed. Sometimes she is interrupted by rainy weather, and it is some days ere she can store up the quantity required.

“A larva found feeding became full-fed in ten days. Six flies were devoured, the heads, harder parts of the throat, portions of the abdomen, and the legs, being left untouched. The larva spins a tough, thin, brown silken cocoon, passes the winter and spring in the larva state, changes to the nymph on the approach of summer, and appears about the beginning of autumn in the perfect state.”

There is a genus of hymenopterous insects known by the name of Scolia, which are remarkable for their fossorial powers. The species represented in the engraving is called Scolia Xantiana, and is a native of California.

When the female Scolia is about to fulfil the great object for which she came into the world, she looks about for a suitable spot, where the ground is not too hard, and digs a perpendicular burrow of some depth, enlarging it at the bottom, and digging horizontally, so that the general shape of the burrow somewhat resembles that of a boot. When the burrow is completed, the insect flies off in search of food for its young, and presently returns, bearing with her a grub, which she clasps tightly under her chest, so that her wings may be at liberty. She then takes the grub to the bottom of the tunnel, deposits an egg upon it, and if the grub be a small one, goes off to fetch another. When a sufficiency of food has been obtained, she covers up the grub and egg and leaves the latter to its fate. In due time it is hatched, and begins straightway to feed upon its unfortunate fellow-prisoner. When all the food is gone, it is old enough to assume the perfect form, and when it finally becomes a perfect insect, it makes its way into the open air, and straightway looks out for a mate.

An European species of this genus, which is called Scolia flavifrons, is remarkable for the four large, round spots on the upper surface of the abdomen. This species always feeds its young on the grub of a beetle, one of the lamellicorn group, and in this case the grub is so large that one is sufficient.

In the illustration, the left hand figure shows a section of the burrow of Scolia Xantiana, and exhibits the enlarged portion of the tunnel in which are placed the young Scolia and the unfortunate grub which has to serve it for food. The insect itself is seen in the centre.

For figures 3 and 4 the reader is referred to the heading “Spiders.”

There is another British insect which feeds its young with flies, and which catches them in a manner somewhat similar to that which has recently been narrated when treating of the Mellinus. The insect in question is called Oxybelus unuglumis, and is a very pretty species. Its length is seldom much more than a quarter of an inch, and its colour is black, with some silvery hair about the face, and with some spots and bands of white, more or less yellowish, upon the pointed abdomen. The male is usually smaller than the female, but compensates for this want of size by his more brilliant colouring.

Mr. F. Smith has described to me the method employed by this insect in catching flies. In the air it would not have a chance of success, and so it proceeds after a fashion very much like that which is adopted by the hunting-spider. Choosing some spot where flies are likely to settle, such as a bare, sunny bank, the Oxybelus alights upon it and begins to run about without any apparent motive. At first the flies are rather alarmed, but after a while they become accustomed to the rapid movements of their foe, and allow it to come nearer and nearer the cause of its perambulations. As soon as it has succeeded in drawing within a few inches of a fly, the Oxybelus leaps upon it, just like the hunting spider on its prey, and flies off before the victim knows that an attack is even meditated.

The burrow of this species is made in hard white sand.

Several species of the genus Cerceris are noted, not only as burrowers, but for the exceeding variety of the food which they store in their dwellings. The most common species, Cerceris arenaria, makes its tunnel in hard, sandy spots, and is usually to be found about the middle of July and August. The length of this insect rather exceeds half an inch, and its colour is black, profusely spotted and barred with yellow. It is rather slenderly made, and gives little external indications of the great strength which it possesses.

This insect prefers to stock its nest with weevils of different kinds—a most singular choice, when the hardness of the exterior is taken into consideration. The well-known nut-weevil (Balaninus nucum), with its hard, round body, and long mouth, is frequently taken by this species of Cerceris, and Mr. Smith further mentions that he has captured it in the act of taking the weevil called Otiorhynchus sulcatus to its nest.

This beetle is among the most noxious of our garden foes, and the more so because its ravages are unseen. In its larval state it infests the roots of many of our succulent plants and flowers, and has a habit of eating away the plant just at the junction of the root and stem. Even flowers in pots are apt to be infested by this insect, and often die without the cause of their death being discovered. It is about half an inch in length, white, and is destitute of feet, their office being performed by bundles of stiff hairs, which are dispersed round the body.

In its perfect state it is about the third of an inch in length, the colour is black, covered with a coating of very fine and short grey hairs, and along its back are a number of short longitudinal grooves. From this latter circumstance it derives its name of “sulcatus,” or grooved.

The exterior of this beetle is extremely hard, even exceptionally so among the hard-bodied weevils. It is extremely difficult to get a pin through the body, and the entomologist is often obliged to bore a hole with a stout needle before the pin can be inserted. Yet, the Cerceris uses this insect as the food of its young, and stores them away in its burrow. That the young should eat them seems as impossible as if a lobster or a box-tortoise had been inserted in their place. It is, however, thought by most practical entomologists that the shell of the weevil is softened by lying in the damp ground, and that as the young is not hatched for several days after the burrow is sealed up, the hard wing cases have time to soften.

Another species of the same genus, Cerceris interrupta, has the curious habit of making its burrow in the hardest ground which it can penetrate, and is generally to be found in well used footpaths. This species also uses weevils for the food of its young, but prefers those small weevils which are classed under the genus Apion, and which are readily known by their pear-shaped bodies and rather elongated heads. [There are about seventy species of Apion, so that the Cerceris has plenty of choice.]

Mason-Bees.

It would not be easy to find a more simple, and, at the same time, ingenious specimen of insect architecture than the nests of those species of solitary bees which have been justly called mason-bees (Megachile, Latreille). Réaumur, who was struck by the analogies between the proceedings of insects and human arts, first gave to bees, wasps, and caterpillars those names which indicate the character of their labours; and which, though they may be considered a little fanciful, are at least calculated to arrest the attention. The nests of mason-bees are constructed of various materials; some with sand, some with earth mixed with chalk, and some with a mixture of earthy substances and wood.

Mason-Bee (Anthophora retusa).—Natural size.

On the north-east wall of Greenwich Park, facing the road, and about four feet from the ground, we discovered (J. R.), December 10th, 1828, the nest of a mason-bee, formed in the perpendicular line of cement between two bricks. Externally there was an irregular cake of dry mud, precisely as if a handful of wet road-stuff had been taken from a cart-rut and thrown against the wall; though, upon closer inspection, the cake contained more small stones than usually occur in the mud of the adjacent cart-ruts. We should in fact have passed it by without notice had there not been a circular hole on one side of it, indicating the perforation of some insect. This hole was found to be the orifice of a cell about an inch deep, exactly of the form and size of a lady’s thimble, finely polished, and of the colour of plaster-of-paris, but stained in various places with yellow.

Exterior Wall of Mason-Bee’s Nest.

This cell was empty; but, upon removing the cake of mud, we discovered another cell, separated from the former by a partition about a quarter of an inch thick, and in it a living bee, from which the preceding figure was drawn, and which, as we supposed, had just changed from the pupa to the winged state, in consequence of the uncommon mildness of the weather. The one which had occupied the adjacent cell had no doubt already dug its way out of its prison, and would probably fall a victim to the first frost.

Cells of a Mason-Bee (Anthophora retusa).—One-third the natural size.

Our nest contained only two cells—perhaps from there not being room between the bricks for more.

[There are only four British species of this genus. One species, A. acervorum, seems perfectly indifferent whether it burrows into banks or into the mortar of old walls. If possible, the former locality seems to be the most favoured.

This species is notable for the many parasites who infect the habitation and destroy the inmates. Perhaps the very worst and most destructive of these parasites is the common earwig, which wreaks wholesale desolation in the nest. It creeps into the burrow, and if it finds a store of pollen laid up for the young, it will eat the pollen. But if the young grub be hatched it will eat the grub. If the inmate be in the pupal state, or even if it be ready to emerge in its perfect condition, the earwig will eat it.

There are two bees which are parasitic upon this unfortunate insect, both belonging the genus Melecta.

But the most destructive of these parasites appears to be an insect which belongs to the great family of Chalcididæ. These insects are of the hymenopterous order, are of very minute dimensions, and of the most brilliant colours. Indeed, if they were an inch or two in length, instead of the eighth or twelfth of an inch, they would not suffer in comparison with the most gorgeous inhabitants of tropical countries.

Their forms are most eccentric, some species having the abdomen small and round and set on a long footstalk, while others have that portion of the body placed so closely against the thorax, that the short footstalk is scarcely visible. Others have certain joints of the legs so large that a single joint equals the entire abdomen. Some have the ovipositor projecting boldly from the body, while others have it tucked up underneath, and others again have it quite short. But there is one point which distinguishes them all, namely, the almost veinless character of the wings.

Some of the Chalcididæ are parasitic upon insects in their earliest stages, actually depositing their eggs in those of moths and butterflies. Others are entirely parasitic upon parasites, laying their eggs in the aphidii, which are parasites of the aphis. Some of them haunt the galls, and contrive to make their young parasitic upon the immature cynipidæ which lie within the gall. The common small tortoise-shell butterfly is terribly infested with these little creatures, and we have bred hundreds of the gem-like Chalcididæ from the larvæ and pupæ of that butterfly.

One of the Chalcididæ, belonging to the genus Melittobia, is a parasite upon the Anthophora; and the curious part of the proceeding is, that it finds there another parasite, which becomes developed in the home of the bee: the Melittobia feeds indiscriminately upon the bee and parasite.

Although the Melittobia does not make such wholesale destruction as is wrought by the earwig when it gets into a nest, it does more damage to the bee, on account of its great numbers. Some three or four females will lay a great quantity of eggs within a nest, and from those eggs a hundred of the young will be developed. When the larvæ are fully grown, they quit their hold of their prey, and fall to the bottom of the cell, where they lie until they have assumed the perfect form. They then burst forth, together with those of the bee that may have escaped their attacks.]

An interesting account is given by Réaumur of another mason-bee (Megachile muraria), not a native of Britain, selecting earthy sand, grain by grain; her glueing a mass of these together with saliva, and building with them her cells from the foundation. But the cells of the Greenwich Park nest were apparently composed of the mortar of the brick wall; though the external covering seems to have been constructed as Réaumur describes his nest, with the occasional addition of small stones.

About the middle of May, 1829, we discovered the mine from which all the various species of mason-bees in the vicinity seemed to derive materials for their nests. (J. R.) It was a bank of brown clay, facing the east, and close by the margin of the river Ravensbourn, at Lee, in Kent. The frequent resort of the bees to this spot attracted the attention of some workmen, who, deceived by their resemblance to wasps, pointed it out as a wasps’ nest; though they were not a little surprised to see so numerous a colony at this early season. As the bees had dug a hole in the bank, where they were incessantly entering and reappearing, we were of opinion that they were a peculiar sort of the social earth-bees (Bombi). On approaching the spot, however, we remarked that the bees were not alarmed, and manifested none of the irritation usual in such cases, the consequence of jealous affection for their young. This led us to observe their operations more minutely; and we soon discovered that on issuing from the hole each bee carried out in its mandibles a piece of clay. Still supposing that they were social earth-bees, we concluded that they were busy excavating a hollow for their nest, and carrying off the refuse to prevent discovery. The mouth of the hole was overhung, and partly concealed, by a large pebble. This we removed, and widened the entrance of the hole, intending to dig down and ascertain the state of the operations; but we soon found that it was of small depth. The bees, being scared away, began scooping out clay from another hole about a yard distant from the first. Upon our withdrawing a few feet from the first hole, they returned thither in preference, and continued assiduously digging and removing the clay. It became obvious, therefore, from their thus changing place, that they were not constructing a nest, but merely quarrying for clay as a building material. By catching one of the bees (Osmia bicornis) when it was loaded with its burden, we ascertained that the clay was not only carefully kneaded, but was also more moist than the mass from which it had been taken. The bee, therefore, in preparing the pellet, which was nearly as large as a garden-pea, had moistened it with its saliva, or some similar fluid, to render it, we may suppose, more tenacious, and better fitted for building. The reason of their digging a hole, instead of taking clay indiscriminately from the bank, appeared to be for the purpose of economizing their saliva, as the weather was dry, and the clay at the surface was parched and hard. It must have been this circumstance which induced them to prefer digging a hole, as it were, in concert, though each of them had to build a separate nest.

The distance to which they carried the clay was probably considerable, as there was no wall near, in the direction they all flew towards, upon which they could build; and in the same direction also, it is worthy of remark, they could have procured much nearer the very same sort of clay. Whatever might be the cause of their preference, we could not but admire their extraordinary industry. It did not require more than half a minute to knead one of the pellets of clay; and, from their frequent returns, probably not more than five minutes to carry it to the nest, and apply it where wanted. From the dryness of the weather, indeed, it was indispensable for them to work rapidly, otherwise the clay could not have been made to hold together. The extent of the whole labour of forming a single nest may be imagined, if we estimate that it must take several hundred pellets of clay for its completion. If a bee work fourteen or fifteen hours a-day, therefore, carrying ten or twelve pellets to its nest every hour, it will be able to finish the structure in about two or three days; allowing some hours of extra time for the more nice workmanship of the cells in which the eggs are to be deposited, and the young grubs reared.

That the construction of such a nest is not a merely agreeable exercise to the mason-bee has been sufficiently proved by M. Du Hamel. He has observed a bee (Megachile muraria) less careful to perform the necessary labour for the protection of her offspring than those we have described, but not less desirous of obtaining this protection, attempt to usurp the nest which another had formed. A fierce battle was invariably the consequence of this attempt; for the true mistress would never give place to the intruder. The motive for the injustice and the resistance was an indisposition to further labour. The trial of strength was probably, sometimes, of as little use in establishing the right as it is amongst mankind; and the proper owner, exhausted by her efforts, had doubtless often to surrender to the dishonest usurper.

The account which Réaumur has given of the operations of this class of bees differs considerably from that which we have here detailed; from the species being different, or from his bees not having been able to procure moist clay. On the contrary, sand was the chief material used by the mason-bees (Megachile muraria); which they had the patience to select from the walks of a garden, and knead into a paste or mortar, adapted to their building. They had consequently to expend a much greater quantity of saliva than our bees (Osmia bicornis), which worked with moist clay. Réaumur, indeed, ascertained that every individual grain of sand is moistened previous to its being joined to the pellet, in order to make it adhere more effectually. The tenacity of the mass is, besides, rendered stronger, he tells us, by adding a proportion of earth or garden-mould. In this manner, a ball of mortar is formed, about the size of a small shot, and carried off to the nest. When the structure of this is examined, it has all the appearance externally of being composed of earth and small stones or gravel. The ancients, who were by no means accurate naturalists, having observed bees carrying pellets of earth and small stones, supposed that they employed these to add to their weight, in order to steady their flight when impeded by the wind.

The nests thus constructed appear to have been more durable edifices than those which have fallen under our observation;—for Réaumur says they were harder than many sorts of stone, and could scarcely be penetrated with a knife. Ours, on the contrary, do not seem harder than a piece of sun-baked clay, and by no means so hard as brick. One circumstance appeared inexplicable to Réaumur and his friend Du Hamel, who studied the operations of these insects in concert. After taking a portion of sand from one part of the garden-walk, the bees usually took another portion from a spot almost twenty and sometimes a hundred paces off, though the sand, so far as could be judged by close examination, was precisely the same in the two places. We should be disposed to refer this more to the restless character of the insect than to any difference in the sand. We have observed a wasp paring the outside of a plank, for materials to form its nest; and though the plank was as uniform in the qualities of its surface, nay, probably more so than the sand could be, the wasp fidgeted about, nibbling a fibre from one, and a fibre from another portion, till enough was procured for one load. In the same way, the whole tribe of wasps and bees flit restlessly from flower to flower, not unfrequently revisiting the same blossom, again and again, within a few seconds. It appears to us, indeed, to be far from improbable, that this very restlessness and irritability may be one of the springs of their unceasing industry.

By observing, with some care, the bees which we found digging the clay, we discovered one of them (Osmia bicornis) at work upon a nest, about a gunshot from the bank. The place it had chosen was the inner wall of a coal-house, facing the south-west, the brick-work of which was but roughly finished. In an upright interstice of half an inch in width, between two of the bricks, we found the little architect assiduously building its walls. The bricklayer’s mortar had either partly fallen out, or been removed by the bee, who had commenced building at the lower end, and did not build downwards, as the social wasps construct their cells.

The very different behaviour of the insect here, and at the quarry, struck us as not a little remarkable. When digging and preparing the clay, our approach, however near, produced no alarm; the work went on as if we had been at a distance; and though we were standing close to the hole, this did not scare away any of the bees upon their arrival to procure a fresh load. But if we stood near the nest, or even in the way by which the bee flew to it, she turned back or made a wide circuit immediately, as if afraid to betray the site of her domicile. We even observed her turning back, when we were so distant that it could not reasonably be supposed she was jealous of us; but probably she had detected some prowling insect depredator, tracking her flight with designs upon her provision for her future progeny. We imagined we could perceive not a little art in her jealous caution, for she would alight on the tiles as if to rest herself; and even when she had entered the coal-house, she did not go directly to her nest, but again rested on a shelf, and at other times pretended to examine several crevices in the wall, at some distance from the nest. But when there was nothing to alarm her, she flew directly to the spot, and began eagerly to add to the building.

It is in instances such as these, which exhibit the adaptation of instinct to circumstances, that our reason finds the greatest difficulty in explaining the governing principle of the minds of the inferior animals. The mason-bee makes her nest by an invariable rule; the model is in her mind, as it has been in the mind of her race from their first creation: they have learnt nothing by experience. But the mode in which they accomplish this task varies according to the situations in which they are placed. They appear to have a glimmering of reason, employed as an accessary and instrument of their instinct.

Cells of Mason-Bees, built, in the first and second figures, by Osmia bicornis between bricks, and in the third, by Megachile muraria in the fluting of an old pilaster.—About half the natural size.

The structure, when finished, consisted of a wall of clay supported by two contiguous bricks, enclosing six chambers, within each of which a mass of pollen, rather larger than a cherry-stone, was deposited, together with an egg, from which in due time a grub was hatched. Contrary to what has been recorded by preceding naturalists with respect to other mason-bees, we found the cells in this instance quite parallel and perpendicular; but it may also be remarked, that the bee itself was a species altogether different from the one which we have described above as the Anthophora retusa, and agreed with the figure of the one we caught quarrying the clay—(Osmia bicornis).

[In Mr. F. Smith’s elaborate catalogue of the British hymenoptera there is a most interesting account of the habits of this insect, which is the most abundant species of the genus, and is spread not only over the whole of England, but over the continent, being found as far south as Italy and as far north as Lapland.

“In a hilly country, or at the sea-side, it chooses the sunny side of cliffs or sandy banks in which to form its burrows, but in cultivated districts, particularly if the soil be clayey, it selects a decayed tree, preferring the stump of an old willow. It lays up a store of pollen and honey for the larvæ, which when full grown, spins a tough dark brown cocoon, in which they remain in the larval state until the autumn, when the majority change to pupæ, and soon arrive at their perfect condition. Many, however, pass the winter in the larva state. In attempting to account for so remarkable a circumstance, all must be conjecture, but it is not of unfrequent occurrence. This species frequently makes its burrows in the mortar of old walls.”

Another species (Osmia bicolor) sometimes makes its cells in very peculiar situations. When obliged to have recourse to its natural powers, it uses its limbs right well, attacks the hard sandy banks, and works at them with the greatest perseverance. But it will not work one stroke where it can avoid the necessity, and in many cases, it contrives to avoid work with much ingenuity.

Lying hidden under hedges, bushes, grass, and herbage, are sure to be shells of various snails, such as the common garden-snail, and the banded-snail, whose diversified shell is the delight of children. These shells the bee thinks are as good as ready-made burrows, and she uses them accordingly.

She goes to the end of the shell, carrying her materials with her, and then builds a cell, and fills it with pollen and honey. Another cell is then made, and yet another, until the shell is nearly filled. As the shell widens, the Osmia places two cells side by side, and when the insect has worked within a short distance of the mouth, she places the cells horizontally, so as to fill up the space. There are several specimens of these curious habitations in the British Museum.

When the whole series of cells is completed, the bee closes up the entrance with little morsels of earth, bits of stick and little stones, all strongly glued together with some very adhesive substance.

Another species (Osmia parietina) has much simpler habits, and is much easier satisfied with a dwelling. This insect merely looks out for a flattish stone lying on the ground, and crawls under it to see if there is any hollow. If so, it attaches the cocoons to the stone and leaves them. On one stone, seen in the British Museum, no less than two hundred and thirty cocoons were placed, although the stone is only ten inches in length by six in width.

This insect is almost wholly confined to the north of England.]

There was one circumstance attending the proceedings of this mason-bee which struck us not a little, though we could not explain it to our own satisfaction. Every time she left her nest for the purpose of procuring a fresh supply of materials, she paid a regular visit to the blossoms of a lilac-tree which grew near. Had these blossoms afforded a supply of pollen, with which she could have replenished her cells, we could have easily understood her design; but the pollen of the lilac is not suitable for this purpose, and that she had never used it was proved by all the pollen in the cells being yellow, whereas that of the lilac is of the same pale purple colour as the flowers. Besides, she did not return immediately from the lilac-tree to the building, but always went for a load of clay. There seemed to us, therefore, to be only two ways to explain the circumstance:—she must either have applied to the lilac-blossoms to obtain a refreshment of honey, or to procure glutinous materials to mix with the clay.

When employed upon the building itself, the bee exhibited the restless disposition peculiar to most hymenopterous[P] insects; for she did not go on with one particular portion of her wall, but ran about from place to place every time she came to work. At first, when we saw her running from the bottom to the top of her building, we naturally imagined that she went up for some of the bricklayer’s mortar to mix with her own materials; but upon minutely examining the walls afterwards, no lime could be discovered in their structure similar to that which was apparent in the nest found in the wall of Greenwich Park.

Réaumur mentions another sort of mason-bee, which selects a small cavity in a stone, in which she forms her nest of garden-mould moistened with gluten, and afterwards closes the whole with the same material.

Cells of Chalicodoma.

[In the accompanying illustration is shown a series of cells which are constructed by an insect which is closely related to the rose-cutter bee of our own country, to which it bears a close resemblance.

It is a native of South Africa, and its name is Chalicodoma cœlocerus. The insect is about half an inch in length, and the colour of the head and body is black, that of the abdomen being brick red.

The nest is made of mud, which is collected by the patient insect and stuck against walls, trunks of trees, and similar localities. In this lump of mud the insect excavates a small number of burrows, each of which contains several cells. If the reader will refer to the central burrow, he will see that it is divided into three cells. The specimen from which this drawing is taken may be seen in the British Museum.

There is another South African insect which makes its mud nest, and fastens it against trees and walls. This is called Synagris calida, and its colour is almost dingy black, the only exception being the red tip to the abdomen. The holes seen in the engraving are the apertures through which the young brood has escaped into the world. The nest is represented of half its natural size.]

Mining-Bees.

A very small sort of bees (Andrenæ), many of them not larger than a house-fly, dig in the ground tubular galleries little wider than the diameter of their own bodies. Samouelle says, that all of them seem to prefer a southern aspect; but we have found them in banks facing the east, and even the north. Immediately above the spot where we have described the mason-bees quarrying the clay, we observed several holes, about the diameter of the stalk of a tobacco-pipe, into which those little bees were seen passing. The clay here was very hard; and on passing a straw into the hole as a director, and digging down for six or eight inches, a very smooth circular gallery was found, terminating in a thimble-shaped horizontal chamber, almost at right angles to the entrance and nearly twice as wide. In this chamber there was a ball of bright yellow pollen, as round as a garden pea, and rather larger, upon which a small white grub was feeding; and to which the mother bee had been adding, as she had just entered a minute before with her thighs loaded with pollen. That it was not the male, the load of pollen determined; for the male has no apparatus for collecting or transporting it. The whole labour of digging the nest and providing food for the young is performed by the female. The females of the solitary bees have no assistance in their tasks. The males are idle; and the females are unprovided with labourers, such as the queens of the hive command.

Cell of Mining-Bee (Andrena).—About half the natural size.

Réaumur mentions that the bees of this sort, whose operations he had observed, piled up at the entrance of their galleries the earth which they had scooped out from the interior; and when the grub was hatched, and properly provided with food, the earth was again employed to close up the passage, in order to prevent the intrusion of ants, ichneumon-flies, or other depredators. In those which we have observed, this was not the case; but every species differs from another in some little peculiarity, though they agree in the general principles of their operations.

[The genus Andrena is an exceedingly large one, nearly seventy species being acknowledged in England alone. They choose various situations for their nest; a very favourite situation is a hard-trodden pathway; into this the bees burrow for some six or seven inches, and often drive their tunnels to a depth of ten inches. Digging up these habitations is not a very easy task, because the tunnel does not run straight, but turns aside when a stone or any similar obstacle comes in the way, and in getting out the stone the burrow is mostly broken. The only method of digging out the nest successfully is either by pushing a small twig up the hole, and using it as a guide, or by filling the entire hole with cotton wool, so as to prevent the earth from falling in.

The commonest species is Andrena albicans. Its length is rather less than half an inch, and its colour is black, with a thick coating of rich red hair on the upper part of the thorax. This species is plentiful on the continent, and is found as far south as Italy. But it is equally capable of enduring great cold, as it has been captured in the Arctic regions. Sometimes the bee will not trouble itself to make a number of separate burrows, but will drive short supplementary tunnels from the side of the first burrow, so that they all open into one common entrance.

The Andrenæ are remarkable for the parasites with which they are infested, the most curious of which is that tiny strepsipterous insect called the Stylops.

One of the Andrenæ, called Colletes Daviesana, is remarkable for the character of its burrow. Like many of the insects which have already been described, it seems indifferent whether it burrows in sand-banks or into the mortar of walls, provided that in the latter case the mortar is soft and friable.

The insect burrows a hole which is very deep in proportion to its size, the little bee being only the third of an inch in length, and the burrows some eight or ten inches in depth. When the mother Colletes has finished her tunnel, she lines the end of it with a thin kind of membrane, which has been well compared by Mr. F. Smith to goldbeater’s skin. This lining is intended to enable the bee to store honey in the cell, as, if there were no such protection, the honey would soak in the ground and be lost.

Having stored up enough food for a single offspring, she shuts it off by a partition of the same membranous substance as the lining. Her next care is to make a thimble-like cup at the end, so as to have a double lining where the honey is to come, and then she puts a fresh supply in the new cell. This cell is then closed, and the bee proceeds with her work until she has made from six to eight cells in a single burrow. This insect suffers terribly from the depredations of the earwig, which completely empties the burrow both of food and of inhabitants. The colour of the insect is black, with a little reddish down on the upper part of the thorax, and some white on the legs. The abdomen is shining black, but each segment has a very narrow band of reddish down on its edge.

In 1850, Mr. F. Smith, to whose works such constant reference has been made, undertook the study of a genus of mining-bees belonging to this family. The species which he chiefly watched is Halictus morio, and his observations are peculiarly valuable, as showing the wonderful manner in which the economy of the race is managed. It is known that in these and many other insects, the pregnant females pass the winter in a state of hibernation, and begin to work in the following spring, and that therefore some arrangement must be needful that a supply of such queens should be kept up.

Mr. Smith found the case to stand thus. Early in April, the females appeared abundantly, and could be seen until June, but not a single male was to be found. During June and July, almost all the Halicti had disappeared, the reason being, that the queens had made their burrows, laid their eggs, stocked their cells, and then died, the duties of their life having been fulfilled. In the middle of August, the males began to appear, and in September the females of the first brood came out. They immediately set to work at their burrows, and laid their eggs. The ground, thoroughly warmed by the summer sun, soon hastened the young through their changes, and in an incredibly short time the insects of the second brood made their appearance. The females of this brood meet their mates, and then hide themselves until the following spring.

As in the case of Andrenæ, several tunnels are often made with one common entrance. The insect is very small, scarcely exceeding the sixth of an inch in length. The head and thorax are a dark green, the abdomen is white, and the legs are covered with silvery hairs. It is a plentiful insect, and is found haunting the holes of old walls.

Passing to another family of British mining-bees, we come to one species that is remarkable not only for its form, but for its economy. This is the Eucera longicornis, the only known species that inhabits England. In form it is chiefly remarkable from the fact that the antennæ of the male are as long as the entire body. The pupa of this insect is enclosed in a thin membrane, and when the male insect is about to emerge from its pupal shell, it has recourse to a rather curious expedient. At the base of the first joint of the front feet there is a bold notch. When the insect wishes to remove the thin membranous pellicle which envelopes the antennæ, it lays these organs in the notch, draws them through, and thus easily strips off the pellicle. The antennæ are most beautifully formed, the surface of each joint being marked with an elaborate pattern like net-work, so that they form beautiful objects for the microscope.

The soil preferred by the Eucera is of a clayey nature. When it has completed the burrow, it presses the soil at the extremity with all its might, and smooths it so carefully that the burrow becomes capable of holding honey without needing any lining. The insect is generally found about the end of May or beginning of June, and in some places is found in great numbers. The ground colour of the insect is black, but the body is covered with a coating of short dun hairs. The length rather exceeds half an inch.]

[CHAPTER III.]

CARPENTER-BEES; CARPENTER-WASPS; UPHOLSTERER-BEES.

Carpenter-Bees.

Among the solitary bees are several British species, which come under that class called carpenter-bees by M. Réaumur, from the circumstance of their working in wood, as the mason-bees work in stone. We have frequently witnessed the operations of these ingenious little workers, who are particularly partial to posts, palings, and the wood-work of houses which has become soft by beginning to decay. Wood actually decayed, or affected by dry-rot, they seem to reject as unfit for their purposes; but they make no objections to any hole previously drilled, provided it be not too large; and, like the mason-bees, they not unfrequently take possession of an old nest, a few repairs being all that in this case is necessary.

When a new nest is to be constructed, the bee proceeds to chisel sufficient space for it out of the wood with her jaws. We say her, because the task in this instance, as in most others of solitary bees and wasps, devolves solely upon the female, the male taking no concern in the affair, and probably being altogether ignorant that such a work is going forward. It is, at least, certain that the male is never seen giving his assistance, and he seldom, if ever, approaches the neighbourhood. The female carpenter-bee has a task to perform no less arduous than the mason-bee; for though the wood may be tolerably soft, she can only cut out a very small portion at a time. The successive portions which she gnaws off may be readily ascertained by an observer, as she carries them away from the place. In giving the history of a mason-wasp (Odynerus), at page 22, we remarked the care with which she carried to a distance little fragments of brick, which she detached in the progress of excavation. We have recently watched a precisely similar procedure in the instance of a carpenter-bee forming a cell in a wooden post. (J. R.) The only difference was, that the bee did not fly so far away with her fragments of wood as the wasp did; but she varied the direction of her flight every time: and we could observe that, after dropping, the chip of wood which she had carried off, she did not return in a direct line to her nest, but made a circuit of some extent before wheeling round to go back.

On observing the proceedings of this carpenter-bee next day, we found her coming in with balls of pollen on her thighs; and on tracing her from the nest into the adjacent garden, we saw her visiting every flower which was likely to yield her a supply of pollen for her future progeny. This was not all; we subsequently saw her taking the direction of the clay quarry frequented by the mason-bees, as we have mentioned in page 41, where we recognised her loading herself with a pellet of clay, and carrying it into her cell in the wooden post. We observed her alternating this labour for several days, at one time carrying clay, and at another pollen; till at length she completed her task, and closed the entrance with a barricade of clay, to prevent the intrusion of any insectivorous depredator, who might make prey of her young; or of some prying parasite, who might introduce its own eggs into the nest she had taken so much trouble to construct.

Some days after it was finished, we cut into the post, and exposed this nest to view. It consisted of six cells of a somewhat square shape, the wood forming the lateral walls; and each was separated from the one adjacent by a partition of clay, of the thickness of a playing card. The wood was not lined with any extraneous substance, but was worked as smooth as if it had been chiseled by a joiner. There were five cells, arranged in a very singular manner—two being almost horizontal, two perpendicular, and one oblique.

The depth to which the wood was excavated in this instance was considerably less than what we have observed in other species which dig perpendicular galleries several inches deep in posts and garden-seats; and they are inferior in ingenuity to the carpentry of a bee described by Réaumur (Xylocopa violacea), which has not been ascertained to be a native of Britain, though a single indigenous species of the genus has been doubtingly mentioned, and is figured by Kirby and Spence, in their valuable ‘Monographia.’ If it ever be found here, its large size and beautiful violet-coloured wings will render mistakes impossible.

Cells of Carpenter-Bees, excavated in an old post.
In fig. A the cells contain the young grubs; in fig. B the cells are empty. Both figures are shown in section, and about half their natural size.

The violet carpenter-bee usually selects an upright piece of wood, into which she bores obliquely for about an inch; and then, changing the direction, works perpendicularly, and parallel to the sides of the wood, from twelve or fifteen inches, and half an inch in breadth. Sometimes the bee is contented with one or two of these excavations; at other times, when the wood is adapted to it, she scoops out three or four—a task which sometimes requires several weeks of incessant labour.

A represents a part of an espalier prop, tunnelled in several places by the violet Carpenter-Bee: the stick is split, and shows the nests and passages by which they are approached. B, a portion of the prop, half the natural size. C, a piece of thin stick, pierced by the Carpenter-Bee, and split, to show the nests. D, perspective view of one of the partitions. E, Carpenter-Bee (Xylocopa violacea). F, Teeth of the Carpenter-Bee, greatly magnified; a, the upper side; b, the lower side.

The tunnel in the wood, however, is only one part of the work; for the little architect has afterwards to divide the whole into cells, somewhat less than an inch in depth. It is necessary, for the proper growth of her progeny, that each should be separated from the other, and be provided with adequate food. She knows, most exactly, the quantity of food which each grub will require during its growth; and she therefore does not hesitate to cut it off from any additional supply. In constructing her cells, she does not employ clay, like the bee which we have mentioned above, but the sawdust, if we may call it so, which she has collected in gnawing out the gallery. It would not, therefore, have suited her design to scatter this about, as our carpenter-bee did. The violet-bee, on the contrary, collects her gnawings into a little store-heap for future use, at a short distance from her nest. She proceeds thus:—At the bottom of her excavation she deposits an egg, and over it fills a space nearly an inch high with the pollen of flowers, made into a paste with honey. She then covers this over with a ceiling composed of cemented sawdust, which also serves for the floor of the next chamber above it. For this purpose she cements round a wall a ring of wood-chips taken from her store-heap; and within this ring forms another, gradually contracting the diameter till she has constructed a circular plate, about the thickness of a crown-piece, and of considerable hardness. This plate of course exhibits concentric circles, somewhat similar to the annual circles in the cross section of a tree. In the same manner she proceeds till she has completed ten or twelve cells; and then she closes the main entrance with a barrier of similar materials.

Let us compare the progress of this little joiner with a human artisan—one who has been long practised in his trade, and has the most perfect and complicated tools for his assistance. The bee has learnt nothing by practice; she makes her nest but once in her life, but it is then as complete and finished as if she had made a thousand. She has no pattern before her—but the Architect of all things has impressed a plan upon her mind, which she can realize without scale or compasses. Her two sharp teeth are the only tools with which she is provided for her laborious work; and yet she bores a tunnel, twelve times the length of her own body, with greater ease than the workman who bores into the earth for water, with his apparatus of augurs adapted to every soil. Her tunnel is clean and regular; she leaves no chips at the bottom, for she is provident of her materials. Further, she has an exquisite piece of joinery to perform when her ruder labour is accomplished. The patient bee works her rings from the circumference to the centre, and she produces a shelf, united with such care with her natural glue, that a number of fragments are as solid as one piece.

The violet carpenter-bee, as may be expected, occupies several weeks in these complicated labours; and during that period she is gradually depositing her eggs, each of which is successively to become a grub, a pupa, and a perfect bee. It is obvious, therefore, as she does not lay all her eggs in the same place—as each is separated from the other by a laborious process—that the egg which is first laid will be the earliest hatched; and that the first perfect insect, being older than its fellows in the same tunnel, will strive to make its escape sooner, and so on of the rest. The careful mother provides for this contingency. She makes a lateral opening at the bottom of the cells; for the teeth of the young bees would not be strong enough to pierce the outer wood, though they can remove the cemented rings of sawdust in the interior. Réaumur observed these holes, in several cases; and he further noticed another external opening opposite to the middle cell, which he supposed was formed, in the first instance, to shorten the distance for the removal of the fragments of wood in the lower half of the building.

* * * * *

That bees of similar habits, if not the same species as the violet-bee, are indigenous to this country, is proved by Grew, who mentions, in his ‘Rarities of Gresham College,’ having found a series of such cells in the middle of the pith of an elder branch, in which they were placed lengthwise, one after another, with a thin boundary between each. As he does not, however, tell us that he was acquainted with the insect which constructed these, it might as probably be allied to the Ceratina albilabris, of which Spinola has given so interesting an account in the ‘Annales du Muséum d’Histoire Naturelle’ (x. 236). This noble and learned naturalist tells us, that one evening he perceived a female ceratina alight on the branch of a bramble, partly withered, and of which the extremity had been broken; and, after resting a moment, suddenly disappear. On detaching the branch, he found that it was perforated, and that the insect was in the very act of excavating a nidus for her eggs. He forthwith gathered a bundle of branches, both of the bramble and the wild-rose, similarly perforated, and took them home to examine them at leisure. Upon inspection, he found that the nests were furnished like those of the same tribe, with balls of pollen kneaded with honey, as a provision for the grubs.

The female ceratina selects a branch of the bramble or wild-rose which has been accidentally broken, and digs into the pith only, leaving the wood and bark untouched. Her mandibles, indeed, are not adapted for gnawing wood; and, accordingly, he found instances in which she could not finish her nest in branches of the wild-rose, where the pith was not of sufficient diameter.

The insect usually makes her perforation a foot in depth, and divides this into eight, nine, or even twelve cells, each about five lines long, and separated by partitions formed by the gnawings of the pith, cemented by honey, or some similar glutinous fluid, much in the same manner with the Xylocopa violacea, which we have already described.

[This species is probably Ceratina cærulea, as the second species, C. albilabris, seems to have little claim to be considered as a British insect. It is plentiful in spots where it resides, but is very local. It can best be found by collecting all the specimens of bramble branches that have holes bored into the pith.

Mr. F. Smith says of this tiny bee, “Some years ago I observed a small bee most industriously employed in excavating a dead bramble stick. My attention was directed to the circumstance from observing some of the fallen pieces of pith on the ground immediately beneath. Occasionally fresh quantities of dust were pushed out. At length, the little creature came out of the stick as if to rest, and after sunning itself for a few minutes, it re-entered, and again commenced its labours. Later in the day, after stopping up the entrance, I cut off the branch and found in it a male and female ceratina.”

The ceratina is only the sixth of an inch in length, and is deep shining blue in colour.

There are many other species of British bees which frequent the stems of bramble and other trees. One of them is known as Prosopis signata. The cells made by the bees of this genus are lined with a membrane, and are stocked with liquid honey. Some species will not take the trouble of boring a tunnel for themselves, but will make use of hollow stones, or similar localities, and place in them the silk-covered cocoons.

There are species of that versatile genus Osmia (O. leucomelana), in the habit of burrowing into dead bramble branches. The mother insect bores a hole some six inches in length, throwing the pieces of pith away, and then, depositing at the bottom an egg and a supply of food, she forms a cell by fixing across the burrow a stopper made of masticated leaves.

The stopper retains its place firmly, because the bee does not eat away the whole of the pith, but alternately widens and contracts the diameter of the burrow, each contracted portion being the termination of a cell. The perfect insect appears in the early summer of the following year.]

A, B, represent sections of old wooden posts, with the cells of the Carpenter-Wasp. In fig. A the young grubs are shown feeding on the insects placed there for their support by the parent wasp. The cells in fig. B contain cocoons. C, Carpenter-Wasp, natural size. D, cocoon of a Carpenter-Wasp, composed of sawdust and wings of insects.

Carpenter-Wasps.

As there are mason-wasps similar in economy to mason-bees, so are there solitary carpenter-wasps which dig galleries in timber, and partition them out into several cells by means of the gnawings of the wood which they have detached. This sort of wasp is of the genus Eumenes. The wood selected is generally such as is soft, or in a state of decay; and the hole which is dug in it is much less neat and regular than that of the carpenter-bees, while the division of the chambers is nothing more than the rubbish produced during the excavation.

The provision which is made for the grub consists of flies or gnats piled into the chamber, but without the nice order remarkable in the spiral columns of green caterpillars provided by the mason-wasp (Odynerus murarius). The most remarkable circumstance is, that in some of the species, when the grub is about to go into the pupa state, it spins a case (a cocoon), into which it interweaves the wings of the flies whose bodies it has previously devoured. In other species, the gnawings of the wood are employed in a similar manner.

[Some of the solitary wasps are also carpenters, and the genus Crabro has several species which are classed under this head. There is, for example, Crabro clavipes, a little black insect with red and black abdomen, that burrows into dead bramble sticks, boring out the pith, and forming a series of cells in the narrow tube thus made. Sometimes this insect bores into decaying wood, but its general home is the bramble-stick. The same habits are common to several other British species of this genus, and the reader will find that old, decaying willow trees are chiefly visited by these pretty little insects. Their store of food, which they lay up for their young, mostly consists of dipterous insects, and various species of gnats are used for this purpose.

Another of the carpenter-wasps (Pemphredon lugubris) is really a useful insect. It makes its burrows in posts, rails, and similar localities, and provides its future young with a large stock of aphides. It has been seen to settle on a rose-bush, scrape off the branches a number of aphides, form them into a ball, and carry them off between its head and front legs.

The colour of this insect is dull black, from which circumstance it derives its name of lugubris. The head is large, and squared, and the abdomen is attached to the thorax by a large footstalk. Its length is about half an inch. It is a very common insect, and is believed to be the only British representation of its genus.

Several species do not take the trouble to form a burrow for themselves, but content themselves with building in holes ready made for them. Straws are favourite resorts of such insects, and in thatched buildings the straws of the roof are often filled with their cells.

One of these insects is a very little species, barely a quarter of an inch in length. Its colour is black, with some silver white hair on the face, and the legs are paler than the body. The abdomen has a long footstalk. Its scientific name is Psen pallipes. Like the insect which has just been described, it provisions its young with aphides.]

Upholsterer-Bees.

In another part of this volume we shall see how certain caterpillars construct abodes for themselves, by cutting off portions of the leaves or bark of plants, and uniting them by means of silk into a uniform and compact texture; but this scarcely appears so wonderful as the prospective labours of some species of bees for the lodgment of their progeny. We allude to the solitary bees, known by the name of the leaf-cutting bees, but which may be denominated more generally upholsterer-bees, as there are some of them which use other materials beside leaves.

One species of our little upholsterers has been called the poppy-bee (Osmia papaveris, Latr.), from its selecting the scarlet petals of the poppy as tapestry for its cells. Kirby and Spence express their doubts whether it is indigenous to this country: we are almost certain that we have seen the nests in Scotland. (J. R.) At Largs, in Ayrshire, a beautiful sea-bathing village on the Firth of Clyde, in July, 1814, we found in a footpath a great number of the cylindrical perforations of the poppy-bee. [In his catalogue of British Hymenoptera, Mr. F. Smith makes the following remarks with regard to this insect. "The poppy-bee, Anthocopa papaveris, is closely allied to this genus (Osmia), and may indeed be placed before it as a connecting link with the Osmia. This interesting insect (l’abeille Tapissiere), of Réaumur, has been supposed to inhabit this country, specimens having been placed in the collection at the British Museum. But it was with much regret that I discovered, when engaged upon the catalogue of British bees for the Museum, and had occasion to examine each individual specimen with care, that in the first place there was no satisfactory evidence of the locality, and that in the next place, all the males associated with the series were those of Osmia adunca, of Panzear." For these reasons, this species has been excluded from the list of British bees.] Réaumur remarked that the cells of this bee which he found at Bercy, were situated in a northern exposure, contrary to what he had remarked in the mason-bee, which prefers the south. The cells at Largs, however, were on an elevated bank, facing the south, near Sir Thomas Brisbane’s observatory. With respect to exposure, indeed, no certain rule seems applicable; for the nests of mason-bees which we found on the wall of Greenwich Park faced the north-east, and we have often found carpenter-bees make choice of a similar situation. In one instance, we found carpenter-bees working indifferently on the north-east and south-west side of the same post.

As we did not perceive any heaps of earth near the holes at Largs, we concluded that it must either have been carried off piecemeal when they were dug, or that they were old holes re-occupied (a circumstance common with bees), and that the rubbish had been trodden down by passengers. Réaumur, who so minutely describes the subsequent operations of the bee, says nothing respecting its excavations. One of these holes is about three inches deep, gradually widening as it descends, till it assumes the form of a small Florence flask. The interior of this is rendered smooth, uniform, and polished, in order to adapt it to the tapestry with which it is intended to be hung, and which is the next step in the process.

The material used for tapestry by the insect upholsterer is supplied by the flower-leaves of the scarlet field-poppy, from which she successively cuts off small pieces of an oval shape, seizes them between her legs, and conveys them to the nest. She begins her work at the bottom, which she overlays with three or four leaves in thickness, and the sides have never less than two. When she finds that the piece she has brought is too large to fit the place intended, she cuts off what is superfluous, and carries away the shreds. By cutting the fresh petal of a poppy with a pair of scissors, we may perceive the difficulty of keeping the piece free from wrinkles and shrivelling; but the bee knows how to spread the pieces which she uses as smooth as glass.

When she has in this manner hung the little chamber all around with this splendid scarlet tapestry, of which she is not sparing, but extends it even beyond the entrance, she then fills it with the pollen of flowers mixed with honey, to the height of about half an inch. In this magazine of provisions for her future progeny she lays an egg, and over it folds down the tapestry of poppy-petals from above. The upper part is then filled in with earth; but Latreille says he has observed more than one cell constructed in a single excavation. This may account for Réaumur’s describing them as sometimes seven inches deep; a circumstance which Latreille, however, thinks very surprising.

It will, perhaps, be impossible ever to ascertain, beyond a doubt, whether the tapestry-bee is led to select the brilliant petals of the poppy from their colour, or from any other quality they may possess, of softness or of warmth, for instance. Réaumur thinks that the largeness, united with the flexibility of the poppy-leaves, determines her choice. Yet it is not improbable that her eye may be gratified by the appearance of her nest; that she may possess a feeling of the beautiful in colour, and may look with complacency upon the delicate hangings of the apartment which she destines for her offspring. Why should not an insect be supposed to have a glimmering of the value of ornament? How can we pronounce, from our limited notion of the mode in which the inferior animals think and act, that their gratifications are wholly bounded by the positive utility of the objects which surround them? Why does a dog howl at the sound of a bugle, but because it offends his organ of hearing?—and why, therefore, may not a bee feel gladness in the brilliant hues of her scarlet drapery, because they are grateful to her organs of sight? All these little creatures work, probably, with more neatness and finish than is absolutely essential for comfort; and this circumstance alone would imply that they have something of taste to exhibit, which produces to them a pleasurable emotion.

The tapestry-bee is, however, content with ornamenting the interior only of the nest which she forms for her progeny. She does not misplace her embellishments with the error of some human artists. She desires security as well as elegance; and, therefore, she leaves no external traces of her operations. Hers is not a mansion rich with columns and friezes without, but cold and unfurnished within, like the desolate palaces of Venice. She covers her tapestry quite round with the common earth; and leaves her eggs enclosed in their poppy-case with a certainty that the outward show of her labours will attract no plunderer.

The poppy-bee may be known by its being rather more than a third of an inch long, of a black colour, studded on the head and back with reddish-grey hairs; the belly being grey and silky, and the rings margined with grey above, the second and third having an impressed transversal line.

* * * * *

A species of solitary bee (Anthidium manicatum, Fabricius), by no means uncommon with us, forms a nest of a peculiarly interesting structure. Kirby and Spence say, that it does not excavate holes, but makes choice of the cavities of old trees, key-holes, and similar localities; yet it is highly probable, we think, that it may sometimes scoop out a suitable cavity when it cannot find one; for its mandibles seem equally capable of this, with those of any of the carpenter or mason-bees.

Be this as it may, the bee in question having selected a place suitably sheltered from the weather, and from the intrusion of depredators, proceeds to form her nest, the exterior walls of which she forms of the wool of pubescent plants, such as rose-campion (Lychnis coronaria), the quince (Pyrus cydonia), cats-ears (Stachys lunata), &c. “It is very pleasant,” says Mr. White, of Selborne, “to see with what address this insect strips off the down, running from the top to the bottom of the branch, and shaving it bare with all the dexterity of a hoop-shaver. When it has got a vast bundle, almost as large as itself, it flies away, holding it secure between its chin and its fore-legs.”[Q] The material is rolled up like a ribbon; and we possess a specimen in which one of these rolls still adheres to a rose-campion stem, the bee having been scared away before obtaining her load.

The manner in which the cells of the nest are made seems not to be very clearly understood. M. Latreille says, that, after constructing her nest of the down of quince-leaves, she deposits her eggs, together with a store of paste, formed of the pollen of flowers, for nourishing the grubs. Kirby and Spence, on the other hand, tell us, that “the parent bee, after having constructed her cells, laid an egg in each, and filled them with a store of suitable food, plasters them with a covering of vermiform masses, apparently composed of honey and pollen; and having done this, aware, long before Count Rumford’s experiments, what materials conduct heat most slowly,” she collects the down from woolly plants, and “sticks it upon the plaster that covers her cells, and thus closely envelops them with a warm coating of down, impervious to every change of temperature.” “From later observations,” however, they are "inclined to think that these cells may possibly, as in the case of the humble-bee, be in fact formed by the larva previously to becoming a pupa, after having eaten the provision of pollen and honey with which the parent bee had surrounded it. The vermicular shape, however, of the masses with which the cases are surrounded, does not seem easily reconcilable with this supposition, unless they are considered as the excrement of the larva."[R]

Whether or not this second explanation is the true one, we have not the means of ascertaining; but we are almost certain the first is incorrect, as it is contrary to the regular procedure of insects to begin with the interior part of any structure, and work outwards. We should imagine, then, that the down is first spread out into the form required, and afterwards plastered on the inside to keep it in form, when probably the grub spins the vermicular cells previous to its metamorphosis.

It might prove interesting to investigate this more minutely; and as the bee is by no means scarce in the neighbourhood of London, it might not be difficult for a careful observer to witness all the details of this singular architecture. Yet we have repeatedly endeavoured, but without success, to watch the bees, when loaded with down, to their nests. The bee may be readily known from its congeners, by its being about the size of the hive-bee, but more broad and flattened, blackish-brown above, with a row of six yellow or white spots along each side of the rings, very like the rose-leaf cutter, and having the belly covered with yellowish-brown hair, and the legs fringed with long hairs of a rather lighter colour.

* * * * *

[This bee does not bore a tunnel for herself, but occupies that of some other insect. The nests of this insect are generally to be obtained from old willows, because these trees are so largely bored by the goat-moth caterpillar, and afford ample space for the larva. The woolly substance obtained from the plant is pressed against the sides of the burrow, so as to form a lining. She then makes a series of cells of a similar material, and the young larva, when it is about to change into the pupa state, envelops itself in a silken covering of a brown colour.

It is a curious fact, that the male of this insect is considerably larger than the female, thus reversing the usual order of things among insects. Only one species of this bee is known in England.]

A common bee belonging to the family of upholsterers is called the rose-leaf cutter (Megachile centuncularis, Latr.). The singularly ingenious habits of this bee have long attracted the attention of naturalists; but the most interesting description is given by Réaumur. So extraordinary does the construction of their nests appear, that a French gardener having dug up some, and believing them to be the work of a magician, who had placed them in his garden with evil intent, sent them to Paris to his master, for advice as to what should be done by way of exorcism. On applying to the Abbé Nollet, the owner of the garden was soon persuaded that the nests in question were the work of insects; and M. Réaumur, to whom they were subsequently sent, found them to be the nests of one of the upholsterer-bees, and probably of the rose-leaf cutter, though the nests in question were made of the leaves of the mountain ash (Pyrus aucuparia).

The rose-leaf cutter makes a cylindrical hole in a beaten pathway, for the sake of more consolidated earth (or in the cavities of walls or decayed wood), from six to ten inches deep, and does not throw the earth dug out from it into a heap, like the Andrenæ.[S] In this she constructs several cells about an inch in length, shaped like a thimble, and made of cuttings of leaves (not petals), neatly folded together, the bottom of one thimble-shaped cell being inserted into the mouth of the one below it, and so on in succession.

Rose-leaf cutter Bees, and Nest lined with rose-leaves.

It is interesting to observe the manner in which this bee procures the materials for forming the tapestry of her cells. The leaf of the rose-tree seems to be that which she prefers, though she sometimes takes other sorts of leaves, particularly those with serrated margins, such as the birch, the perennial mercury (Mercurialis perennis), mountain-ash, &c. She places herself upon the outer edge of the leaf which she has selected, so that its margin may pass between her legs. Turning her head towards the point, she commences near the footstalk, and with her mandibles cuts out a circular piece with as much expedition as we could do with a pair of scissors, and with more accuracy and neatness than could easily be done by us. As she proceeds, she keeps the cut portion between her legs, so as not to impede her progress; and using her body for a trammel, as a carpenter would say, she cuts in a regular curved line. As she supports herself during the operation upon the portion of the leaf which she is detaching, it must be obvious, when it is nearly cut off, that the weight of her body might tear it away, so as to injure the accuracy of its curvilineal shape. To prevent any accident of this kind, as soon as she suspects that her weight might tear it, she poises herself on her wings, till she has completed the incision. It has been said, by naturalists, that this manœuvre of poising herself on the wing, is to prevent her falling to the ground, when the piece gives way; but as no winged insect requires to take any such precaution, our explanation is probably the true one.

With the piece which she has thus cut out, held in a bent position perpendicularly to her body, she flies off to her nest, and fits it into the interior with the utmost neatness and ingenuity; and, without employing any paste or glue, she trusts, as Réaumur ascertained, to the spring the leaf takes in drying, to retain it in its position. It requires from nine to ten pieces of leaf to form one cell, as they are not always of precisely the same thickness. The interior surface of each cell consists of three pieces of leaf, of equal size, narrow at one end, but gradually widening at the other, where the width equals half the length. One side of each of the pieces is the serrated margin of the leaf from which it was cut, and this margin is always placed outermost, and the cut margin innermost. Like most insects, she begins with the exterior, commencing with a layer of tapestry, which is composed of three or four oval pieces, larger in dimensions than the rest, adding a second and a third layer proportionately smaller. In forming these, she is careful not to place a joining opposite to a joining, but with all the skill of a consummate artificer, lays the middle of each piece of leaf over the margins of the others, so as by this means both to cover and strengthen the junctions. By repeating this process, she sometimes forms a fourth or a fifth layer of leaves, taking care to bend the leaves at the narrow extremity or closed end of the cell, so as to bring them into a convex shape.

When she has in this manner completed a cell, her next business is to replenish it with a store of honey and pollen, which, being chiefly collected from thistles, forms a beautiful rose-coloured conserve. In this she deposits a single egg, and then covers in the opening with three pieces of leaf, so exactly circular, that a pair of compasses could not define their margin with more accuracy. In this manner the industrious and ingenious upholsterer proceeds till the whole gallery is filled, the convex extremity of the one fitting into the open end of the next, and serving both as a basis and as the means of strengthening it. If, by any accident, the labour of these insects is interrupted or the edifice deranged, they exhibit astonishing perseverance in setting it again to rights. Insects, indeed, are not easily forced to abandon any work which they may have begun.

The monkish legends tell us that St. Francis Xavier, walking one day in a garden, and seeing an insect, of the Mantis genus, moving along in its solemn way, holding up its two fore legs, as in the act of devotion, desired it to sing the praises of God. The legend adds that the saint immediately heard the insect carol a fine canticle with a loud emphasis. We want no miraculous voice to record the wonders of the Almighty hand, when we regard the insect world. The little rose-leaf cutter, pursuing her work with the nicest mathematical art—using no artificial instruments to form her ovals and her circles—knowing that the elastic property of the leaves will retain them in their position—making her nest of equal strength throughout, by the most rational adjustment of each distinct part—demands from us something more than mere wonder; for such an exercise of instinctive ingenuity at once directs our admiration to the great Contriver, who has so admirably proportioned her knowledge to her necessities.

[CHAPTER IV.]

CARDER-BEES; HUMBLE-BEES; SOCIAL-WASPS.

The bees and wasps, whose ingenious architecture we have already examined, are solitary in their labours. Those we are about to describe live in society. The perfection of the social state among this class of insects is certainly that of the hive-bees. They are the inhabitants of a large city, where the arts are carried to a higher excellence than in small districts enjoying little communication of intelligence. But the bees of the villages, if we may follow up the parallel, are not without their interest. Such are those which are called carder-bees and humble-bees.

Carder-Bees.

The nests of the bees which Réaumur denominates carders (Bombus muscorum, Latr.) are by no means uncommon, and are well worth the study of the naturalist. During the hay harvest, they are frequently met with by mowers in the open fields and meadows; but they may sometimes be discovered in hedge-banks, the borders of copses, or among moss-grown stones. The description of the mode of building adopted by this bee has been copied by most of our writers on insects from Réaumur; though he is not a little severe on those who write without having ever had a single nest in their possession. We have been able to avoid such a reproach; for we have now before us a very complete nest of carder-bees, which differs from those described by Réaumur, in being made not of moss, but withered grass. With this exception, we find that his account agrees accurately with our own observations. (J. R.)

Fig. A represents two Carder-Bees heckling moss for their Nests; B, exterior view of the Nest of the Carder-Bee.

The carder-bees select for their nest a shallow excavation about half a foot in diameter; but when they cannot find one to suit their purpose, they undertake the Herculean task of digging one themselves. They cover this hollow with a dome of moss—sometimes, as we have ascertained, of withered grass. They make use, indeed, of whatever materials may be within their reach; for they do not attempt to bring anything from a distance, not even when they are deprived of the greater portion by an experimental naturalist. Their only method of transporting materials to the building is by pushing them along the ground—the bee, for that purpose, working backwards, with its head turned from the nest. If there is only one bee engaged in this labour, as usually happens in the early spring, when a nest is founded by a solitary female who has outlived the winter, she transports her little bundles of moss or grass by successive backward pushes, till she gets them home.

In the latter part of the season, when the hive is populous and can afford more hands, there is an ingenious division of this labour. A file of bees, to the number sometimes of half a dozen, is established, from the nest to the moss or grass which they intend to use, the heads of all the file of bees being turned from the nest and towards the material. The last bee of the file lays hold of some of the moss with her mandibles, disentangles it from the rest, and having carded it with her fore legs into a sort of felt or small bundle, she pushes it under her body to the next bee, who passes it in the same manner to the next, and so on till it is brought to the border of the nest,—in the same way as we sometimes see sugar-loaves conveyed from a cart to a warehouse, by a file of porters throwing them from one to another.

The elevation of the dome, which is all built from the interior, is from four to six inches above the level of the field. Beside the moss or grass, they frequently employ coarse wax to form the ceiling of the vault, for the purpose of keeping out rain, and preventing high winds from destroying it. Before this finishing is given to the nest, we have remarked, that on a fine sunshiny day the upper portion of the dome was opened to the extent of more than an inch, in order, we suppose, to forward the hatching of the eggs in the interior; but on the approach of night this was carefully covered in again. It was remarkable that the opening which we have just mentioned was never used by the bees for either their entrance or their exit from the nest, though they were all at work there, and, of course, would have found it the readiest and easiest passage; but they invariably made their exit and their entrance through the covert-way or gallery which opens at the bottom of the nest, and, in some nests, is about a foot long and half an inch wide. This is, no doubt, intended for concealment from field-mice, polecats, wasps, and other depredators.

On removing a portion of the dome and bringing the interior of the structure into view, we find little of the architectural regularity so conspicuous in the combs of a common bee-hive: instead of this symmetry, there are only a few egg-shaped, dark-coloured cells, placed somewhat irregularly, but approaching more to the horizontal than to the vertical position, and connected together with small amorphous[T] columns of brown wax. Sometimes there are two or three of these oval cells placed one above another, without anything to unite them.

These cells are not, however, the workmanship of the old bees, but of their young grubs, who spin them when they are about to change into nymphs. But, from these cases, when they are spun, the enclosed insects have no means of escaping, and they depend for their liberation on the old bees gnawing off the covering, as is done also by ants in the same circumstances. The instinct with which they know the precise time when it is proper to do this is truly wonderful. It is no less so, that these cocoons are by no means useless when thus untenanted, for they subsequently serve for honey-pots, and are indeed the only store-cells in the nest. For this purpose the edge of the cell is repaired and strengthened with a ring of wax.

Breeding-Cells.

The true breeding-cells are contained in several amorphous masses of brown-coloured wax, varying in dimensions, but of a somewhat flat and globular shape. On opening any of these, a number of eggs or grubs are found, on whose account the mother bee has collected the masses of wax, which also contain a supply of pollen moistened with honey, for their subsistence.

The number of eggs or grubs found in one spheroid of wax varies from three to thirty, and the bees in a whole nest seldom exceed sixty. There are three sizes of bees, of which the females are the largest; but neither these nor the males are, as in the case of the hive-bee, exempt from labour, the females, indeed, always found the nests, since they alone survive the winter, all the rest perishing with cold. In each nest, also, are several females, that live in harmony together.

Interior views of Carder-Bee’s Nest.

The carder-bees may be easily distinguished from their congeners (of the same genus), by being not unlike the colour of the withered moss with which they build their nests, having the fore part of their back a dull orange, and hinder part ringed with different shades of greyish yellow. They are not so large as the common humble-bee (Bombus terrestris, Latr.), but rather shorter and thicker in the body than the common hive-bee (Apis mellifica).

Lapidary-Bees.

A bee still more common, perhaps, than the carder is the orange-tailed bee, or lapidary (Bombus lapidaria), readily known by its general black colour and reddish orange tail. It builds its nest sometimes in stony ground, but prefers a heap of stones such as are gathered off grass fields or are piled up near quarries. Unlike the carder, the lapidary carries to its nest bits of moss, which are very neatly arranged into a regular oval. These insects associate in their labours; and they make honey with great industry. The individuals of a nest are more numerous than the carders, and likewise more pertinaciously vindictive. About two years ago we discovered a nest of these bees at Compton-Bassett, in Wiltshire, in the centre of a heap of limestone rubbish; but owing to the brisk defensive warfare of their legionaries, we could not obtain a view of the interior. It was not even safe to approach within many yards of the place; and we do not exaggerate when we say that several of them pursued us most pertinaciously about a quarter of a mile. (J. R.)

Humble-Bees.

The common humble-bee (Bombus terrestris) is precisely similar in its economy to the two preceding species, with this difference, that it forms its nest underground like the common wasp, in an excavated chamber, to which a winding passage leads, of from one to two feet, and of a diameter sufficient to allow of two bees passing. The cells have no covering beside the vault of the excavation and patches of coarse wax similar to that of the carder-bee.

[The accompanying illustration represents a group of cells made by this species. As may be seen by reference to the engraving, they are not placed with any regularity, but seem to be tossed about at random.

Some of the cells contain larvæ, in others, those closely sealed, lie the pupæ in different stages of development, and some of the cells are filled with a very fragrant and sweet honey, which, however, is injurious to many persons, giving them severe and persistent headaches, even though taken in small quantities.]

Social-Wasps.

The nest of the common wasp (Vespa vulgaris) attracts more or less the attention of everybody; but its interior architecture is not so well known as it deserves to be, for its singular ingenuity, in which it rivals even that of the hive-bee (Apis mellifica). In their general economy the social or republican wasps closely resemble the humble-bee (Bombus), every colony being founded by a single female who has survived the winter, to the rigours of which all her summer associates of males and working wasps uniformly fall victims. Nay, out of three hundred females which may be found in one vespiary, or wasp’s nest, towards the close of autumn, scarcely ten or a dozen survive till the ensuing spring, at which season they awake from their hibernal lethargy, and begin with ardour the labours of colonization.

It may be interesting to follow one of these mother wasps through her several operations, in which she merits more the praise of industry than the queen of a bee-hive, who does nothing, and never moves without a numerous train of obedient retainers, always ready to execute her commands and to do her homage. The mother wasp, on the contrary, is at first alone, and is obliged to perform every species of drudgery herself.

Her first care, after being roused to activity by the returning warmth of the season, is to discover a place suitable for her intended colony; and, accordingly, in the spring, wasps may be seen prying into every hole of a hedge-bank, particularly where field-mice have burrowed. Some authors report that she is partial to the forsaken galleries of the mole; but this does not accord with our observations, as we have never met with a single vespiary in any situation likely to have been frequented by moles. But though we cannot assert the fact, we think it highly probable that the deserted nest of the field-mouse, which is not uncommon in hedge-banks, may be sometimes appropriated by a mother wasp as an excavation convenient for her purpose. Yet, if she does make choice of the burrow of a field-mouse, it requires to be afterwards considerably enlarged in the interior chamber, and the entrance gallery very much narrowed.

The desire of the wasp to save herself the labour of excavation, by forming her nest where other animals have burrowed, is not without a parallel in the actions of quadrupeds, and even of birds. In the splendid continuation of Wilson’s American Ornithology, by Charles L. Bonaparte (whose scientific pursuits have thrown around that name a beneficent lustre, pleasingly contrasted with his uncle’s glory), there is an interesting example of this instinctive adoption of the labours of others. "In the trans-Mississippian territories of the United States, the burrowing-owl resides exclusively in the villages of the marmot, or prairie-dog, whose excavations are so commodious as to render it unnecessary that the owl should dig for himself, as he is said to do where no burrowing animals exist.[U] The villages of the prairie-dog are very numerous and variable in their extent,—sometimes covering only a few acres, and at others spreading over the surface of the country for miles together. They are composed of slightly-elevated mounds, having the form of a truncated cone, about two feet in width at the base, and seldom rising as high as eighteen inches from the surface of the soil. The entrance is placed either at the top or on the side, and the whole mound is beaten down externally, especially at the summit, resembling a much-used footpath. From the entrance, the passage into the mound descends vertically for one or two feet, and is thence continued obliquely downwards until it terminates in an apartment, within which the industrious prairie-dog constructs, on the approach of cold weather, a comfortable cell for his winter’s sleep. The cell, which is composed of fine dry grass, is globular in form, with an opening at top, capable of admitting the finger; and the whole is so firmly compacted, that it might without injury be rolled over the floor."[V]

In case of need the wasp is abundantly furnished by nature with instruments for excavating a burrow out of the solid ground, as she no doubt most commonly does—digging the earth with her strong mandibles, and carrying it off or pushing it out as she proceeds. The entrance gallery is about an inch or less in diameter, and usually runs in a winding or zig-zag direction, from one to two feet in depth. In the chamber to which this gallery leads, and which, when completed, is from one to two feet in diameter, the mother wasp lays the foundations of her city, beginning with the walls.

The building materials employed by wasps were long a matter of conjecture to scientific inquirers; for the bluish-grey papery substance of the whole structure has no resemblance to any sort of wax employed by bees for a similar purpose. Now that the discovery has been made, we can with difficulty bring ourselves to believe that a naturalist so acute and indefatigable as M. Réaumur, should have, for twenty years, as he tells us, endeavoured, without success, to find out the secret. At length, however, his perseverance was rewarded. He remarked a female wasp alight on the sash of his window, and begin to gnaw the wood with her mandibles; and it struck him at once that she was procuring materials for building. He saw her detach from the wood a bundle of fibres about a tenth of an inch in length, and finer than a hair; and as she did not swallow these, but gathered them into a mass with her feet, he could not doubt that his first idea was correct. In a short time she shifted to another part of the window-frame, carrying with her the fibres she had collected, and to which she continued to add, when he caught her, in order to examine the nature of her bundle; and he found that it was not yet moistened nor rolled into a ball, as is always done before employing it in building. In every other respect it had precisely the same colour and fibrous texture as the walls of a vespiary. It struck him as remarkable that it bore no resemblance to wood gnawed by other insects, such as the goat-moth caterpillar, which is granular like sawdust. This would not have suited the design of the wasp, who was well aware that fibres of some length form a stronger texture. He even discovered, that before detaching the fibres, she bruised them (les charpissoit) into a sort of lint (charpie) with her mandibles. All this the careful naturalist imitated by bruising and paring the same wood of the window-sash with his penknife, till he succeeded in making a little bundle of fibres scarcely to be distinguished from that collected by the wasp.

We have ourselves frequently seen wasps employed in procuring their materials in this manner, and have always observed that they shift from one part to another more than once in preparing a single load—a circumstance which we ascribe entirely to the restless temper peculiar to the whole order of hymenopterous insects. Réaumur found that the wood which they preferred was such as had been long exposed to the weather, and is old and dry. White of Selborne, and Kirby and Spence, on the contrary, maintain that wasps obtain their paper from sound timber, hornets only from that which is decayed.[W] Our own observations, however, confirm the statement of Réaumur with respect to wasps, as, in every instance which has fallen under our notice, the wood selected was very much weathered; and in one case, an old oak post in a garden at Lee, in Kent, half destroyed by dry-rot, was seemingly the resort of all the wasps in the vicinity. In another case, the deal bond in a brick wall, which had been built thirty years, is at this moment (June, 1829) literally striped with the gnawings of wasps, which we have watched at the work for hours together. (J. R.)