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Operations of Caterpillar upon leaf ..... 246 106. Lichen-tents and Caterpillars .... . . 247 107. Branch of willow with Caterpillars' muft'-tents . . . 251 108. Eose-leaf mined by Caterpillars ..... 253 109. Bramble-leaf do 254 110. Primrose-leaf do. ....... 255 111. Bark mined by Beetle-Grubs 259 112. Cocoons of Bhagiuni and Rhynocopliorus .... 261 113. Capricorn-Beetle rounding off bark of tree . . . 262 114. Cerambyx carcharias, and Cerambyx populneus . . . 263 115. The Mole-Cricket 265 XIV Illustrations. 116. Nest of Mole-Cricket 117. Acrida Verrucivora depositing her eggs 118. Transformations of the Cockchafer . 119. Ant-hive or Formicary . 120. Floor of Ant-nest . . • • 121. Insecure Nest propped up by Ants . 122. Nest of Wood- Ant .... 123. Artificial Formicary 124. Portion of a tree tunnelled by Jet Ants 125. Formica fuliginosa .... 126. Crematogaster .... 127. Nests of Polyracliis bispinosa and P. textor 128. Termes hellicosus in the winged state 129. Queeu Termite distended with eggs . ^ 130. Tree-nest of Termites arhorum, and Hill-nests of 131. Turret-nests of White Ants 132. Leg and Pro-leg of Caterpillar 133. Caterpillar of Goat-Moth 134. Interior structure of Cossus 13.5. Side view and section of Silk -tube of Cossus 136. Labium of Cossus ,^ 137. Cocoons of Emperor-Moth 138. Cocoon of Arctia villica . 139. Net-work Cocoon . 1^0. Nest of Puss-Moth 141. Caterpillars of small Ermine on Siberian crab 142. Winter-nests of Porthesia chrysorrhoea 143. Winter-nests of Social Caterpillars . 144. Pendulous Leaves . 145. Nest of Larracla . 146. Nests of Polyhia . 147. Nests of Oiketicus, &c. . 148. Nests of Pelopxus, &c. . 149. Bombycidie . 150. Processionary Caterpillars 151. Nest of do. 152. Garden Spider suspended by single thread 153. Spinnerets of Spiders ... 154. Single thread of Spider, greatly magnified 155. Attached end of Spider's thread 156. Geometric Net of Epeira diadema . 157. Nest of the Mason-Spider 158. Nest of Mygale sauvagesii T. hellicosus Illustrations. XV J 59. Insect emerginj^ from its Nest . 160. Triple-clawed Foot of Spider . 161. Small Galls on Oak-leaf . 162. Ovipositor of Gall-Fly . 163. Gall-Fly and mechanism of ovipositor 164. Bedeguar Gall of the Rose 165. One of the bristles of Bedeguar, magnified 166. Artichoke Gall of the Oak-bud, and Insect 167. Leafy gall of Dyer's Broom 168. Semi-gall of the Hawtliorn 169. Woolly Gall of the Oak . 170. Oak-apple Galls . 171. Koot-galls of the Oak 172. Woody Gall on a Willow Branch 173. Currant-gall of the catkins of the Oak 174. Gall of the Hawthorn-Weevil . 175. Plant-Louse, magnified ... 176. Galls produced on the Poplar, and Insects 177. Leaf of the Currant-bush with Aphides 178. Shoot of Lime-ti'ee contorted by A. tiliee 179. Pseudo-gall of the Bramble 1 80. Pseudo-galls of the Hawthorn 181. Ovipositor of the Breeze-Fly 182. The Grub of Breeze-Fly . 183. The Ox-Breeze-Fly 184. Bumps produced on cattle by Breeze-Fly 185. Microgaster glomeratus 186. Microgaster alveolarius . , , PAGE 391 395 398 399 400 402 403 405 406 408 409 410 411 412 413 414 416 417 419 421 422 423 426 432 433 434 438 439 INSECT ARCHITECTURE. CHAPTER 1. INTRODUCTION. T T 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 cvery-day life is spent. With regard to our own existence, the pulsation of the heart, the act of respiration, the volun- tary 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 oiFer anything like a satisfactory solution of these phenomena, and how far are we still from an accurate and comj)lete knowledge of them ! The science of Meteorology, which attempts to ex2)lain 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 2 Insect Architecture. to compreliend 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 imderstanding 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 admii'e. 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 every- where 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 om* 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 oui- 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 pro- visions and most abimdant resources of a creative Provi- dence ; and the better do we appreciate our own relations with all the infinite varieties of nature, and our dependence, in common with the ephemeron thnt flutters its little horn- in the summer sun, upon that Being in whose scheme of existence the humblest as well as the highest creature has its Introduction. 3 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 demonstra- tion 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 thi-ough 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 jdoasm-es, then we may without hesita- tion affirm, that the study of insects is one of the most delightful branches of natural history, for it affords peculiar facilities for its pm'suit. These facilities are found in the almost inexhaustible variety which insects present to the cmious 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 Jime and the beginning of August, he foimd, in the vicinity of Eij)ley, specimens of above two thousand fom- hundred species of insects, exclusive of caterpillars and grubs, — a number amounting to nearly a foiu'th of the insects ascertained to be indigenous. He fm-ther tells us, that, among these sj)ecimens. although the groimd had, in former seasons, been fi-equently 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 con- siderable plenty.* 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 disajDpear altogether, the next— a fact strikingly illustrated by the uncommon abundance, in 1826 and 1827, of the seven-spot lady-bii'd (CocchieUa septempimdata), in the vicinity of London, though during the two succeeding summers this insect was * Stephens' Illustrations, vol. i., p. 72, note. 4 Insect Architecture. comparatively scarce, wLile the small two-spot lady-bird (Coccinella hipundata) was i^lentiful. There is, perhaps, no situation in which the lover of nature and the observer of animal life may not find oppor- tunities 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 per- secuted creature are among the most extraordinary exhibi- tions of mechanical ingenuity ; and a daily watching of the workings of its instinct would beget admiration in a riglitly- constituted mind. The poor prisoner had abundant leisure for the speculations in which the sj)ider'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 leism-e, and probably want of knowledge, have prevented us from following uj) 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 factSj and soon became the disciple and the friend of the Pliny of France'"* (Eeaumur). 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 gi'atification 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 pm-pose of observing the * Contemplation de la Nature, part ii. cb. 42. latroiuetion. 5 insects we might meet with in the wood : but wc had not got far among the bushes, when heavy rain came on. We iuimediatcly 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, slieltered 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 hoiu's 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.* It w'ill api^ear, then, from the preceding observations, that cabinets and collections, though undoubtedly of the highest use, are by no means indisj)ensable, as the observer of natm'e 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 * The original observations in this volume wliich are marked by the initials J. R., are by J. Kennie, A.M., A.L.S., and those which are enclosed in brackets are bv the" Rev. J G. Wood, JI.A., F.L.S. 6 Insect Architecture. because then everything ap^jears 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 aifords us a succession of "ever-new delights," such as charmed us in childhood, when every- thing 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 with- draw 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 {echantillons), 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. Eousseau, for example, was passionately fond of the Linntean botanjr, even to the driest minutife of its technicalities ; and yet it does not appear to have cramped his mind, or impoverished his imagination. If Eousseau, 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 natui-alists. 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 Linnsean orders of insects into Latin hexameters, the manuscript of which is still preserved in his interleaved copy of the ' Systema Naturae.' Introduction. 7 Further, to use the somewhat exaggerated words of Kirby and Spence, whoso 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 Eomans, 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 Eedi, Malpighi, Vallisnicri, Swammerdam, Leeuwenhoek, Eeaumur, Linnjeus, De Geer, Bonnet, and the Hubers '? and at home, what philosophers have done more honour to their country and to human nature than Eay, Willughby, Lister, and Derham ? Yet all these made the study of insects one of their most favourite pursuits."* 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 : — " 0 ! would the sons of men once think their eyes And reason given them but to study Flies ! See Kature, 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."t Thus exclaims the Goddess of Dulness, sweeping into her net all those who study natm'e 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 * Introduction to Entomology, vol. i. t Dunciad, book iv. 8 Insect Architecture. own comfort and security. The injui-ies wliicli 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 wi'itten document of a hundred years' existence. " What development," he adds, " can the civilization of a people assume, if there be nothing to connect the jsresent 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 ?" * Again, there are beetles which deposit their larvfe in trees in such formi- dable numbers that whole forests perish beyond the power of remedy. The pines of the Hartz have thus been de- stroyed 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 * Humboldt, Voyage, lib. vii., cli. 20. Introduction. 9 the United States were in the habit of destroying the red- headed woodpecker, the great enemy of these insects, because he occasionally spoilt an apple.* The same delight- ful Avi'itcr and true naturalist, speaking of the labours of the ivory-billed woodi^ecker, says, " Would it be believed that the larvte of an insect or fly, no lai-ger 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."f 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. J The corn-weevil, which extracts the flour from gi'ain, leaving the husk behind, will destroy the contents of the largest storehouses in a very short period. The wire-worm and the tui"nip-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 troiiical 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 ; lor a knowledge of tlieir structm'e, 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 * Amer. Oraith., i., p. 144. f Ibid., iii., p. 21. { Bkmienbach ; see also Insect Tiansfoi mations, p. 231. 10 Insect Architecture. against tlie destructive propensities of insects wliicli are offensive to man. But a plailosophical study of natural history will teach us that the direct benefits which insects confer iJ^on us are even less important than their general uses in maintaining the economy of the world. The mis- chiefs 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 hyaena 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 wc know not how to escape their ravages, flocks of lady-bii'ds 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 desii-e 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 Introdudion. 1 1 Barrington calls liinisclf — is well calculated to streugthen 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 wliich -differ in many minute points, but whose general similarity of appear- ance 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 diflicult 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 know- ledge of things should go along with that of words. " If names perish," says Linnaeus, " the knowledge of things perishes also :'" * and, without names, how can any one com- municate 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 generaliza- tions of the dcspisers 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 ad- vancing years ; jDrovided, as most frequently happens, the same system be persisted in, of avoiding or destroying almost every insect which is unlucky enough to attract observation. * Nomina si pere;mt, perit et cognitio lenim. 12 Insect Architecture. 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 (Goerius 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 disagi-eeable 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 retui'ned 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 tm'ned up in a threatening attitude, Inirocluction. 13 and its formidable jaws ready extended for attack or defence.* We do not wish that children should be encoiu-aged to expose themselves to danger in their encounters with insects. They should be taiight to avoid those few which are really noxious — to admire all — to injure none. The various beauty of insects — theii" glittering colours, their graceful forms — supplies an inexhaustible source of attraction. Even the most formidable insects, both in ap- pearance 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 ap- pearance, and are painted mth 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. f " See," exclaims Linnaeus, " 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 tlie flight of birds and the brilliancy of the peacock. Consider this insect through the wonderful progress of its life, — how different is the fii'st period of its being from the second, and both from the i:)arent insect! Its changes are an inexpKcable 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 mthout food ; this insect again imdergoes another transformation, acquires wings, and six feet, and becomes a gay butterfly, sporting in the air, and living by suction uj)on the honey of plants. What has nattu'e produced more worthy of our admiration than such an animal, coming ur)on the stage of the world, and playing its part there under so many dif- ferent masks ?" The ancients were so struck with the trans- formations of the butterfly, and its revival from a seeming temporary death, as to have considered it an emblem of the soul, the Greek word pyscJie signifying both the soul and a * J. R., in Slag, of Natural History, vol. i., p. 33-k f Miss Jermyn's Butterfly Collector, p. 11. 14 Insect Architecture. 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 contemiitible, 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 cii'culating 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 admii-ation, 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 beauti- ful gradations by which one species runs into another ? Their difierences 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, alto- gether unlike those manifested in the superior departments of animated nature. These instincts have various direc- Introduction. 15 tions, and are developed in a more or less strildng manner to oui' 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 procm-ing food, and involve many remax'k- able stratagems ; some direct their social economy, and regulate the condition under which they live together either in monarchies or republics, their colonizations, and their migi-ations ; but the most powerful instinct which belongs to insects has regard to the preservation of their siJccies. We find, accordingly, that as the necessity for this preserva- tion is of the utmost importance in the economy of nature, so for this especial object many insects, whose oifspring, 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 pui'pose 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 pupai and chrysalides, is also exercised by many insects for their own preservation against the changes of temperatm-e to which they are exposed, or against their natural enemies. Many species employ those contrivances during the period of their hybernation, or winter sleep. For all these purj)oses 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, w^hich they close ^^•ith the most cm-ious 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 philosoj)hical in- 16 Insect Architecture. quirers, 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 iicld of the most delightful study. The con- struction of theii' 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 Arciiitectuee. In the descriptions which we shall give of Insect Archi- tecture, we shall employ as few technical words as possible : and such as we cannot well avoid, we shall exj^lain in their places ; but, since oiTr subject chiefly relates to the reproduc- tion of insects, it may be useful to many readers to introduce here a brief description of the changes which they undergo. It was of old believed that insects were produced spon- taneously 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 Eedi, a celebrated Italian naturalist, Magnified eggs, of a, Ceonieira armiUata , b, of an unknown water insect ; c, of the lacquey moth ; ((., of a ciddis-fly {Fhrytjanca ati at.a) ; e, of red underwing moth (C'atocato niipta) ; f, of Fontia Brassicce ; g, of the Clifdeu Nonpareil moth. proved by rigid experiments that they are always, in such cases, Latched from eggs previously laid. Most insects, indeed, lay eggs, though some few are viviparous, and some Introduction. 17 propagate boili ways. The eggs of insects are very various in form, and seldom slia2)cd like those of birds. We have here figured those of several species, as they appear ander the microscope. When an insect first issues from the egg, it is called by naturalists larva, aiid, popularly, a caterpillar, a grub, or a maggot. The distinction, in popular language, iseems 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. There are, however, certain larvae, as those of the Cicada, the crickets, the water-boatman (Notonecta), the cock- a, Ametabolous pupa of Cicada; h, caterpillar of tussock moth (Laria fascelina) ; c, larva of the poplar beetle (Cltrysomtla populi); d, larva of Sinex; e, larva of the common gnat. roach, &c., which resemble the perfect insects in form, excepting that they are destitute of wings ; but in the pupa c 18 Insect Architecture. state these appear in a rudimentary condition, at least in sucli species as have wings in tlie mature stage of existence. The pupse are active and eat. Insects, the larvae and pupse of which are so similar to the adults, are termed Ametabolous (a, without, jjLeTaftoXr], change) ; those the larvae of which undergo changes of a marked character, Metaboloiis (Inseda ametabola and Insecta metabola, Burmeister). LarvfB are remarkably small at first, but grow rapidly. The full-grown caterpillar of the goat-moth (Cossus ligni- perda) 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 houi'S, one hundred and fifty-five times heavier than at its birth. Some larvae have feet, others ai"e 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 varioiis forms of insects in this stage of their existence. When larvae are full grown, they cast their skins for the last time, undergo a complete change of form, excejiting in a. Pupa of a Water-Beetle (Ilydi ojjhilus) ; h, pupa of Sphinx TJgiistn. the case of ametabolous larvae, cease to eat, and remain nearly motionless. The inner skin of the larva now becomes con- hitroduction. 19 verted into a membranous or leathery covering, whicli Avi'aps 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 ;* moreover from the pui^as of many of the butterflies appearing gilt as if with gold, the Greeks called them Chrysalides, and the Eomans Aurelice, and hence naturalists frequently call a pupa chrysalis, even when it is not gilt. We shall see, as we proceed, the curious contri- vances resorted to for protecting insects in this helpless state. The following are examples of insects in the imago, or perfect state. Insects iu the Imago or perfect state. a, Xemopteryx coa, Leach. — &, Mip-meleon formicalynx, Fabricius. — c, Hesperia comma, Faekicius. — d, Nepa cinerea, Linnjeus. After a certain time, the insect which has remained in its pupa-case, like a mass of jelly without shape, is gradually * Generally to ametabolous pupae. 20 Insect Architecture. preparing for its final change, when it takes the form of a perfect insect. This state was called by Linnaeus 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 nourish- ment of their larvae. 21 t CHAPTER 11. STRUCTURES FOR PROTECTING EGGS. — MASON-WASPS ; MASON- BEES ; MINING-BEES. THE provisions wliicli 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 them- selves, indeed, are not so liable to depredation and injmy 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 temperatui'C of 108^, while their eggs did not entirely cease to be fertile till 144'. The larvfe of flesh-flies perished, while the eggs of the same species continued fertile, at about the same comparative degi-ees of heat as in the preceding instances. Intense cold has a still less effect upon eggs than extreme heat. Spallanzani exposed the eggs of silkworms to an artificial cold 23" below zero, and yet, in the subsequent sj)ring, they all produced caterpillars. Insects almost in- variably die at the temperature of 14°, that is, at 18° below the freezing point.* 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 secm'e them against the numerous enemies which would attempt their destruction ; and, above all, to protect the grubs, * See Spallanzani's Tracts, by Dalyell, vol. i. 22 Insect Architecture. V, hen they are first developed, from those injuries to which they £re 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 4ihese threads upon spindles, others to the union of many threads into one, — all labouring \\dth invariable precision because they attend te 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 indi- vidual efforts, to accomj^lish their general task, never imped- ing 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 entii'ely 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 tiu'ner of Em'ope, who produces every variety of elegant form by the skilful application of the simplest means. Orn- island abounds with many varieties of solitary wasps and bees ; and theii' nests may therefore be easily discovered by those who, in the proper seasons, are desirous of observing the peculiarities of their architecture. Mason-Wasps, In September, 1828, a common species of solitary mason- wasp (Odynerus, Latr.) was observed by us (J. E.) on the Mason- Wasps. 23 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 gi-ound. Whether there might not have been an accidental hole in the brick before the wasj) 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 neighbom'hood. The most remark- able ch'cumstance 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 detach- ing. It did not appear to suit her design to wear down the brick, particle by particle, as the furniture beetle (Aiiohium Odyncrus.—'SatxiTiil size. pertinax) does in making its pin-hole galleries in old wood. Our wasp- architect, on the contrary, by means of her strong ii-anchant-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-&[es. 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 ciichoo-Qxes, 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 24 Insect Architecture. 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 Mandibles — Jaws of Mason-AVayp. — Greatly magnified. 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 retm'ned to her task in about two or three minutes. 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 Eay and Willughby,* 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 thiclmess of * Ray, Hist. Insect., 254, 3Iason-Was2}s. 25 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. Notwithstanding all the precautions of the careful parent to conceal her nest it was found out by one of the cuckoo flics ( Tarhina larvarum ?) — probably a common species very similar to the house-fly, but rather larger, which deposited Cuckoo-Fly (^Taddfia ^a>-iw«?/i/').- Natural size. an egg there ; and the grub hatched from it, after devouring one of the wasp-grubs, formed itself a cocoon (a), as did the Mason-Wasp's Nost and Cocoons.— About one-third the natural size. other undevoured grub of the wasp (&). Both awaited the retm-n of summer to change into winged insects, bm'st their cerements, and proceed as their parents did. Another mason-wasp (Odynerus miirarius, Late.), difiter- Mason-Wasp (Odynerus murarius). — Natural size. ing little in appearance from the former, may often be seen frequenting sandy banks exposed to the sun, and construct- 26 Insect Architecture. ing its singular burrows. The sort of sand-bank wliicli it selects is bard and compact ; and though this may be more difficult t'o 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 Reaumur 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 recoiu-se, 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. When this wasp has detached a few grains of the moistened sand, it kneads them together into a jiellet about the size of Nests, &c., of Mason-Wasps.— About half tbe natural size. a, Tlie tower of the nest ; 6, the entrance after the tower is removed ; c, the cell ; d, the cell, with a roU of caterpillars prepared for the larva. 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, wliich advances in height as the hole in the sand increases in depth. Every two or three minutes, however, during these operations, it Mason-Wasps. 27 takes a short excursion, for the purpose, probably, of re- plenishing its store of fluid wherewith to moisten the sand. Yet so little time is lost, that Eeaumur 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 architectui-e, is the model followed. The pellets which form the walls of the tower are not very nicely joined, and numer- ous vacuities are left between them, giving it the appearance of filigi-ee-work. That it should be thus slightly built is not sm-prising, 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. Eeaumur 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 creatui'e 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, Eeaumur 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 fm-nish the cell she has thus constructed with pollen and honey, like the solitary bees, but with living caterpillars, and these always of the same 28 Insect Architecture. 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 thera all up, it spins a case, and is transform.ed 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 Eeaumur, " 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 ex- hibits 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 piindum, 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 Mason-Wasps. 29 were thirteen in number, very carefully constructed of earth, and several of them were closed. Although these ceUs were not fossorial iu their nature, several other species of the same genus are as accomplished biUTowers as any insect. Pompilus plumhem, 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 bm'rows, preferring our little white spider as the pro- vision for their young. Although the same insect may be 30 Insect Architecture. often observed to carry the same kind of j)rey 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 svsdft-wiuged insect, black in colour, with a reddish patch on the end of the abdomen. Its name is Tracliytes 2iom])iliformis, 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 grass- hopper— 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 situ- ations, 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 PhUanthus 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 creatm-e, seizing upon various bees and dragging them into its timnel. 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 favour- ites 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 Mason-Wasjis. 31 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 numbei's of that insect. Those that made their burrows at the top of the cliif, took the Andrenoe. Of course, the Philan- thus is obliged to catch more of the Andreuaj 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 wasjjs, on account of their sharply pointed and yellow banded abdomen ; they belong to the genus Crabro, and arc extremely variable in the material into which they burrow, and the insects with which they feed theii" young. Some species burrow into dry bramble sticks. If the reader should wish to obtain speci- mens 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 collect- ing. Sometimes these creatures ai"e 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 theii- tunnels with flies of various kinds. One very useful species, Crabro Icevis, burrows in sand-banks, and provisions its nest with the noxious turnip-fleas [Halticce), great numbers of which are needed to stock a single burrow. It is rather a social insect, many bm-rows 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 buiTowing-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 32 Inseet Architecture. burrowers into the gi'ound, and stock their nests with flies ol some kind. Another species of this large genus, Crahro luteipalpis, is fond of making its burrows in the mortar of old walls, pre- ferring those spots where nails have been drawn, making the process of burrowing easier for the insect. It is not un- common in the outskirts of London. All gardeners, espe- cially those who cultivate roses, ought to encourage this very little insect, and welcome its presence, for it pro- visions 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 Crahro 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 sandbanks, and provisions its bui-rows with gnats. It is tolerably plentiful. Our last example of the earth-burrowers belonging to this genus is Crahro 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 pro- visions 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 Mason- Wasjys. 33 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 futm-e 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 yoimg. There is one of these solitary burrowing wasps called the Astata hoops, 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 tui'nip, 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 coimtry. 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, MelUnus arvensis, and reared it from the larva state, D 34 Insect Architecture. a few observations are here recorded. Wlien the parent insect has formed a bmrow 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 — Muscidce, SyrpliidcB, &c., are captured. " It is amusing to see foui" or five females lie in wait upon a patch of cow-dimg 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 can-ied ofi" by the Mellinus to its bur- row. 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 re- quired. " 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 Xantiaiia, 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 bui-row of some depth, enlarging it at the bot- tom, and digging horizontally, so that the general shape of the burrow somewhat resembles that of a boot. When the biuTpw is completed, the insect flies off in search of food for Maso)i-Was2)S. 6D its young, and presently retiu-ns, bearing with, lier 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 per- fect insect, it makes its way into the open air, and straightway looks out for a mate. An Eui'opean species of this genus, which is called Scolia JJavifrons, 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. 36 Insect Architecture. In the illustration, the left hand figure shows a section of the burrow of Scolia Xaniiana, and exhibits the enlarged por- tion 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 Oxyhelus unuglumis, and is a very pretty species. Its length is sel- dom 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 mthout any aj)parent motive. At fii'st the flies are rather alarmed, but after a while they become accustomed to the rapid moveipents 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 timnel in hard, sandy spots, and is usually to be foixnd about the middle of July and August. Mason-Was2)s. 37 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 prefei"s to stock its nest with weevils of differ- ent kinds — a most singular choice, when the hardness of the exterior is taken into consideration. The well-known nut- weevil {Balaninits 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 captui'ed 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 ofl&ce being per- formed 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 ex- ceptionally so among the hard-bodied weevils. It is ex- tremely difficult to get a pin through the body, and the ento- mologist 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 impossi- ble as if a lobster or a box-tortoise had been inserted in their place. It is, however, thought by most practical entomolo- gists that the shell of the weevil is softened by lying in the damp ground, and that as the young is not hatched for 3S Insect Architecture. several clays after the burrow is sealed up, tlie 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 A^non, and which are readily kno\\Ti by their pear-shaped bodies and rather elongated heads. There are about seventy species of Apio7i, 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 sjjecies of solitary bees which have been justly called mason-bees (Megachile, Latkeille). Reaumur, who was struck by the analogies between the proceedings of insects and human arts, first gave to bees, wasps, and cater- pillars 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. On the north-east wall of Greenwich Park, facing the road, and about four feet from the groimd, we discovered (J. E.), Mason-Bee {Anthophora retvsa). — Natural size. 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 Mason-Bees. 39 tlirown against the wall ; though, upon closer inspection, the cake contained more small stones than iisually occur in the mud of the adjacent cart-ruts. We should in fact have passed it by without notice had there not been a circidar hole on one side of it, indicating the perforation of some insect. Exterior AVall of Mason-Bee's Nesk 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 j)laster-of-paris, but stained in various places with yellow. 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 Cells of a 5Iason-Bee {Anihophora rctusa). — One-third the natural size. 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. 40 Insect Architecture. 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 imfor- tunate 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 ChalcididcB. 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 roimd and set on a long foot-stalk, 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 pro- jecting 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 Ghalcididoe 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 Mason-Bees. 41 of the aphis. Some of them haunt the galls, aud contrive to make their young parasitic upon the immature cynijjidaj which lie within the gall. The common small tortoise-shell butterfly is terribly infested with thcs* little creatui-es, and wo have bred hundreds of the gem-like Chalcididce from the larvfB and pupas of that butterfly. One of the Chalcididce, belonging to the genus Melittuhia, is a jmrasite ujion the Anthophora ; aud the curious jiart of the proceeding is, that it finds there another parasite, which becomes developed in the home of the bee : the Melittuhia feeds indiscriminately ujjon 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 larvae 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 Eeaumur of another mason-bee (Megachile muraria), not a native of Britain, select- ing eai-thy 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 Eeaumur 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. E.) It was a bank of brown clay, facing the east, and close by the margin of the river Eavensboum, 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 42 Insect Architecture. 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 wei^ a peculiar sort of the social earth-bees (Bomhi). 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, there- fore, from their thus changing place, that they were not con- structing a nest, but merely quarrying for clay as a building material. By catching one of the bees (Osmia hicornis) when it was loaded with its bm-den, 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 sui-face was parched and hard. It must have been this cii'cumstance which induced them to prefer digging a hole, as it were, in concert, though each of them had to build a separate nest. Mason-Bees. 43 The distance to which they carried the clay was probably considerable, as there was no wall near, in the direction they all flew towards, ujjon which they could build ; and in the same direction also, it is worthy of reraark, they could have procured much nearer the very same sort of clay. Whatever might be the cause of theii" preference, we could not but admire theii" extraordinary industry. It did not require more than half a minute to knead one of the pellets of clay ; and, from their frequent retm-ns, probably not more than five minutes to carry it to the nest, and apply it where wanted. From the di-yness 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 foiu-teen or fifteen hours a-day, therefore, carrying ten or twelve pellets to its nest every houi', it will be able to finish the structure in about two or three days ; allowing some houi-s of extra time for the more nice workman- ship of the cells in which the eggs are to be deposited, and the young gi-ubs 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 murarici) 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 in- disposition 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 proj)er owner, exhausted by her efforts, had doubtless often to surrender to the dishonest usurper. The account which Eeaumur has given of the operations of this class of bees differs considerably from that which 44 Insect Architecture. we have here detailed ; from the species being diflferent, 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. Eeaumur, 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 struc- ture 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, supj)osed 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 ob- servation ; — for Eeaumur 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 Eeaumur 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 himdred 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 Mason-Bees. 45 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 imfrequently 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 hicornis) at work upon a nest, about a gunshot from the bank. The place it had chosen was the inner wall of a coal-house, faciug 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 ai'chitect 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 theii' 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 deiwedator, tracking her flight with designs upon her provision for her futm-e progeny. We imagined we could perceive not a little art 48 Insect Arehiiedure. 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, hut 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 adapta- tion of instinct to circumstances, that oiu' reason finds the greatest difficulty in exiDlaining the governing princii)le 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 crea- tion : they have learnt nothing by experience. But the mode in which they accomj)lish 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. The structure, when finished, consisted of a wall of clay supported by two contiguous bricks, enclosing six chambers, Cells of Blasoii-Bees, built, in tlie first and second figures, by Osniia bicm-nis between bricks, and in the third, by Megachile viurariu in the fluting of an old pilaster. — About half the natural size. 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 foimd the cells in this instance quite Mason-Bees. 47 parallel and perpendicular ; but it may also be remarked, that tbe bee itself was a species altogether different from the one which we have described above as the Antliopliora 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 biu'rows, 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 lai"V£e, 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 pupas, 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 conjectm'e, but it is not of un- frequent occurrence. This species frequently makes its bur- rows in the mortar of old walls. Another species (Osmia hicolor) sometimes makes its cells in very peculiar situations. When obliged to have recourse to its natm'al 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 sui-e 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 48 Insect Architecture. 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 imme- diately 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. Mason-Bees. 49 Wheu employed upon the building itself, the bee exhibited the restless disposition peculiar to most hymeuopterous * 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 witli 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. Reaumur 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. [In the accompanying illustration is shown a series of cells which are constructed by an insect which is closely related to Cell? of Ckalicudoma. 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 ccelocerus. 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 fifth order of Liunaus ; insects with four transparent veined wings. 50 Insect Arehitedure. The nest Is made of mud, wliich 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 (Andrenoe), many of them not larger than a house-fly, dig in the ground tubular galleries little wider than the diameter of theii- 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 Mining-Bees. 51 gallery was found, terminating in a thimble -shaped liorizontal 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 jiea, and rather larger, upon which a small white gi'ub was feeding ; and to wliich the mother bee liad been adding, as she liad just entered a minute bcfoj'o with her thighs loaded Avith pollen. That it \H Cell of Mining-Bee (^Andrena). — About half the nalural size. was not the male, the load of pollen determined ; for the male has no apparatus for collecting or transporting it. The whole labom- 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 labom-ers, such as the queens of the hive command. Reaumur mentions that the bees of this sort, whose opera- tions 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, ich- nuemon-llies, or other depredators. In those which v,e 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 habita- 52 Insect Architecture. tions 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. Some- times the bee will not trouble itself to make a number of separate burrows, but will drive short supplementary tunnels from the side of the fii"st burrow, so that they all open into one common entrance. The Andrente 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 Andrente, called Colletes Daviesana, is remark- able for the character of its burrow. Like many of the insects which have already been described, it seems in- diiferent whether it burrows in sandbanks 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 land 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 Mining-Bees. 53 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 lias made from six to eight cells in a single burrow. This insect suffers terribly from tlie depredations of the ear- wig, 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 Halidus 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 Halicli had disappeared, the reason being, that the queens had made their burrows, laid theii' eggs, stocked their cells, and then died, the duties of their life having been fulfilled. In the middle of August, the males began to aj)pear, 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 Andrenae, several tunnels are often made with one common entrance. The insect is very small, 54: Insect Architecture. 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 haii-s. It is a plentiful insect, and is found haunting the holes of old w'alls. 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 antennte 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 antenna3, it lays these organs in the notch, draws them through, and thi;s easily strips oif the pellicle. The antennae are most beautifully formed, the surface of each joint being marked with an elaborate pattern like network, 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 cajjable 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.] 55 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. Reaumur, 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. Wlien 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 neighbour- hood. 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 siKJcessive 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, 56 Insect Architecture. which she detached in the progress of excavation. We have recently watched a precisely similai* procedm-e in the instance of a carpenter-bee forming a cell in a wooden post. (J. E.) 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 di-opping, the chip of wood which she had carried off, she did not return in a dii'ect line to her nest, but made a cii'cuit 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 ti-acing 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 her- self 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 in- stance was considerably less than what we have observed in other species which dig perpendicular galleries several inches Carpenter -Bees. 57 deep in posts and garden-scats ; and they are inferior in ingenuity to the carpentry of a bee described by Eeaumur (XylocojM violacea), which has not been ascertained to be a native of Britain, though a single indigenous species of the Cells of Carpenter- Bees, excavated in an old post. In fig. A the eells contain the j'oung grubs; in fig. B the cells are empty. Both figures • are shown in section, and about half their natural size. 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 ^nngs will render mistakes impossible. 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. 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 gi-owth 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 dui'ing its growth ; and 58 Insect Architecture. slie therefore does not hesitate to cut it off from any addi- tional 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 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 pasi^ages 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 (Si/Iocopa violaced). F, Teeth of the Carpenter-Bee, greatly magnified ; a, the upper side ; b, the lower side. suited her design to scatter this about, as our carpenter-bee did. The violet-bee, on the contrary, collects her gna^^dngs 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 Carpenter-Bees. 59 an incli higli with the pollen of flowers, made into a paste vdth honey. She then covers this over with a ceiling com- posed of cemented sawdust, which also serves for the flof^r 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 con- tracting the diameter till she has constructed a circular plate, about the thickness of a crown-jnece, and of considerable hardness. This plate of coiu'se 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 com- pleted 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 im- pressed 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, ^vith greater ease than the workman who bores into the earth for water, ^ith his apparatus of augurs adapted to every soil. Her tunnel is clean and regidar ; 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 vv^orks her rings from the circumference to the centre, and she produces a shelf, united with such care with her natm-al glue, that a number of fragments are as solid as one piece. The violet carpenter-bee, as may be expected, occujiies 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 60 Insect Architecture. 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 tnunel, 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. Eeaumur observed these holes, in several cases ; and he further noticed another external opening opposite to the middle cell, which he sui^posed 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 albilahns, of which Spinola has given so interesting an account in the ' Annales du Museum 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 inspec- tion, 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 Carpenter-Bees. 61 wild-roso wliicli 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 hor 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 Xylorojja viol area, which we have already described. [This species is probably Ceratina ccervlea, as the second species, C. alhilahns, 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 excavat- ing 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 creatm-e 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 oif 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. 62 Insect Archiiedure. There are siJecies of that versatile genus Osmia {0. leucomelana), in the habit of burrowing into dead bramble branches. The mother insect bores a hole some sis inches in length, thi'owing 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 biuTow, each contracted portion being the termination of a cell. The perfect insect aj^pears in the early summer of the following year.] Carpexter-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 iU-^M^ ■■■' ■ 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. of the gna wings 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 Carpenter- Was]3S. 63 tbe carpenter-bees, wliile the division of the chambers is nothing more than the rubbish produced dm-ing the excava- tion. The provision which is made for the gi'ub 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 (Odijnerus vmrarius). The most remarkable circimistance is, that in some of the species, when the gi'ub 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 devom-ed. 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 Crahro has several species which are classed under this head. There is, for example, Crahro 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 vai'ious species of gnats are used for this purpose. Another of the carpenter-wasps (Pemjpliredon luguLris) is really a useful insect. It makes its burrows in posts, rails, and similar localities, and provides its futui-e yoimg 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 coloui" of this insect is dull black, from which cir- cumstance it derives its name of luguhris. 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. 64 Insect Architecture. 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 de- scribed, 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 ofi* 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 tipholsterer-hees, as there are some of them which use other materials beside leaves. One species of our little upholsterers has been called the pojipy-bee (Osmia papaveris, Latr.), from its selecting the scarlet petals of the poppy as tapestry for its cells. Kirby and Spcnce express their doubts whether it is indigenous to this country : we are almost certain that we have seen the nests in Scotland. (J. E.) At Largs, in Ayrshii'e, a beautiful sea-bathing village on the Firth of Clyde, in July, 1814, we found in a footpath a great number of the cylindrical jier- forations of the poppy-bee. [In his catalogue of British Hymenoptcra, Mr. F. Smith makes the following remarks with regard to this insect. " The poppy-bee, AntJiocopa 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 (Vahellle Tajnssiere), of Upholsterer-Bees. 65 Reaumur, has been supposed to inhabit this country, speci- mens 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.] Reamimr remarked that the cells of this bee which he found at Bercy, were situated in a northern exposure, contrary to what lie 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 indiiferentlv 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-occiipied (a circumstance common with bees), and that the rubbish had been trodden down by passengers. Reaumm', who so minutely describes the subsequent opera- tions 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, aud polished, in order to adapt it to the tapestry with which it is intended to be hxmg, 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, fi'om which she successively cuts off small pieces of an oval shape, seizes them between her legs, and conveys them to F 6Q Insect Architecture. the nest. She begins her work at the bottom, which she overlays with three or foui* 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 ofi" what is superfluous, and carries away the shi-eds. 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 Reaumur'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 bril- liant petals of the poppy from their colour, or from any other quality they may possess, of softness or of warmth, for instance. Eeaumur 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 coloui*, and may look with complacency upon the delicate hangings of the apart- ment 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 Uljiliohierer-Bees. 67 offends his organ of licariug '? — and wliy, therefore, may not a bee feel ghidness in the brilliant hues of her scarlet di-apery, because they are grateful to her organs of sight '? All these little creatui-cs work, probably, with more neat- ness and finish than is absolutely essential for comfort ; and this circumstance alone would imjjly that they have some- thing of taste to exhibit, which produces to them a plea- surable 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 cer- tainty 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 colom-, studded on the head and back ■ndth 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. Kii'by 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 car- penter or mason-bees. Be this as it may, the bee in question having selected a place suitably sheltered from the weather, and from 68 Insect Architecture. 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 lunaia), &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 vnth 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."* The material is rolled up like a ribbon ; and we possess a spe- cimen 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, appa- rently composed of honey and pollen ; and having done this, aware, long before Count Eumford'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 tjie 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 * Naturalist's Calendnr, p. 100. Uplwlsierer-Bees. 69 easily reconcilable with this supposition, unless they arc considered as the excrement of the larva."* Whether or not this second explanation is the true one, we have not the means of ascertaining ; but we are almost certain the tirst is incorrect, as it is contrary to the regulai' 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 endeavom'ed, 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 biu'row, 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 cm-ious fact, that the male of this insect is consi- * Intioductiou to Entomology, vol. i. p. 435, 5th edit. 70 Insect Architecture. derably 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 (ATegachile centuncularis, Latr.). The singularly ingenious habits of this bee have long attracted the attention of naturalists ; but the most interest- ing description is given by Eeaumur. So extraordinary does the construction of their nests appear, that a French gar- nener 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 Abbe NoUet, the owner of the garden was soon per- suaded that the nests in question were the work of insects ; and M. Eeaumur, 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 dxig out from it into a heap, like the Andrense.* 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. 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, * See p. 50. Upliolsterer-Bees. 71 &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 com- mences near the footstalk, and with her mandibles cuts out a circular piece with as much expedition as we could do with a j^air 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 Eose-leaf cutter Bees, and Nest lined with rose-leaves. impede her progress ; and using her body for a trammel, as a carpenter would say, she cuts in a regular cui'ved 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 cui'vilineal shape. To prevent any accident of this kind, as soon as she suspects that her weight might tear it, she 72 Insect Architedure. poises herself on her wings, till she has completed the incision. It has been said, by naturalists, that this man- oeuvre 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 Reaumur 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 thi-ee 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 nai'row 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 Uphohferer-Bees. 73 their margin with mure accui-acy. In this manner the industrious and ingenious upholsterer proceeds till the whole gallery is tilled, 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, desii-ed it to sing the praises of God. The legend adds that the saint imme- diately heard the insect cai'ol 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 viiih 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. 74 Insect Architecture. CHAPTER IV. CABDER-BEES ; HUMBLE-BEES ; SOCIAL-WASl'S. 'T^HE bees and wasps, whose ingenious architectui*e 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. Caedek-Bees. The nests of the bees which Eeaumur denominates carders {Bomhus mtiscorum, Latb.) 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 dis- covered in hedge-banks, the borders of copses, or among moss-grown stones. The description of the mode of build- ing adopted by this bee has been copied by most of our ^^'riters on insects from Eeaumur ; 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 Eeau- mur, in being made not of moss, but withered grass. With this exception, we find that his account agrees accurately with our own observations, (J. E.) The carder-bees select for their nest a shallow excava- Carder-Bees. 75 tiou about half a foot in diameter ; but wlicu tliey cannot find one to suit their purpose, they undertake tho Herculean task of digging one themselves. They cover this hollow \\i\h. a dome of moss— sometimes, as we have ascertained, of withered gi-ass. 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 Fig. A represents two Carder- Bees heckling moss for their Nests ; B, esierior view of the Nest of the Carder- Bee. is by pushing them along the ground — the bee, for that purpose, working backwards, with its head tui-ned 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 76 Insect Architecture. by a solitary female who lias outlived the winter, she trans- ports her little bundles of moss or grass by successive back- ward pushes, till she gets them home. In the latter part of the season, w'hen 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 haK 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 tm-ned 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 fhe 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 destroy- ing 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 theii" exit from the nest, though they were all at work there, and, of com-se, 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. Carder-Bees. 77 Ou 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-colom-ed cells, placed somewhat irregu- larly, but approaching more to the horizontal than to the vertical position, and connected together -with small amor- phous* 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 sj)un, the enclosed insects 'have no means of escaping, and they depend for their liberation on the old bees gna^^•ing 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 wonderfid. 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 ^A-ith a ring of wax. The true breeding-cells are contained in several amor- phous masses of brown-coloured wax, varying in dimensions, BreeditiK-Cells but of a somewhat flat and globular shape. On opening any of these, a number of eggs or gi'ubs are found, on whose * Shapeless. 78 Insect Architecture. 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 sjiheroid 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. Jnterior 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 Lapidary-Bees. — Runible Bees. 79 nests, having the fore part of their back a dull orange, and hinder part ringed with different shades of greyish yellow. They arc 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). LAriDARY-BEES. A bee still more common, perhaps, than the carder is the orange-tailed bee, or lapidary (Bonihus 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 theii" legionaries, we could not obtain a view of the interior. It was not even safe to aj)proach 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. K.) 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 imderground 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 grouj) of cells made by this species. As may be seen by reference to the 80 Insect Architecture. engraving, they are not placed with any regularity, but seem to be tossed about at random. Some of the cells contain larvae, in others, those closely sealed, lie the pupse in different stages of development, and some of the cells are filled with a very fragrant aad 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 architectm'C is not so well known as it deserves to be, for its singiilar 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 (Bonibus), every colony being founded by a single Social-Wasps. 81 female who has sui-vivecl the winter, to the rigours of whicli all her summer associates of males and working wasps uniformly fall victims. Nay, out of three hundred females which may be foimd 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 hybernal 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 fii'st alone, and is obliged to perform every species of drudgery herself. Her first care, after being roused to activity by the return- ing 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, par- ticularly where field-mice have bui-rowed. 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 laboui* of excavation, by forming her nest where other animals have burrowed, is not without a parallel in the actions of quad- rupeds, and even of birds. In the splendid continuation of Wilson's American Ornithology, by Charles L. Bonaparte 82 Insect Architecture. (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-Mississip- pian 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 bui'rowing animals exist.* The villages of the prairie-dog are very nmuerous and variable in their extent, — sometimes covering only a few acres, and at others sjjreading 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 sui'face 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 j^rairie-dog con- structs, 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, wdth an oi^ening at top, capable of admitting the finger ; and the whole is so firmly compacted, that it might without injury be rolled over the floor."t In case of need the wasp is abundantly furnished by nature with instruments for excavating a burrow out of the solid gi'ound, 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 zigzag direction, from one to two feet * The Owl obsei'ved by Vieillot in St. Domingo digs itself a buirow two feet in depth, at the bottom of which it dejiosits its eggs upon a bed of moss. f American Ornithology, by Charles Lucien Bonaparte, vol. i. p. (39. Social-Wasjys. S3 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 structiu'e has no resem- blance 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. Eeaumur, 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 procur- ing materials for building. He saw her detach from the wood a bimdle 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 natm'e of her bundle ; and he foimd 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 cater- pillar, which is granular like sawdust. This would not have suited the design of the wasp, who was well aware that fibres of some lengih form a stronger textui'e. He even discovered, that before detaching the fibres, she bruised them (les charpissoif) into a sort of lint (cJiarpie) with her mandibles. All this the careful natui-alist imitated by bruising and paring the same wood of the window-sash with his penknife, till he succeeded in making a little bundle of 84 Insect Architecture. fibres scarcely to be distinguisliecl from tbat collectetl by the wasp. We have ourselves frequently seen wasps employed in procm-ing 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 hymen opterous insects. Eeaumur found that the wood which they preferred was such as had been long ex- posed to the weather, and is old and diy. White of Sel- borne, and Kirby and Spence, on the contrary, maintain that wasps obtain their paper from sound timber, hornets only from that which is decayed.* Our own observations, however, confirm the statement of Eeaumur with respect to wasj)s, 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 vfall, which had been built thirty years, is at this moment (June, 1829) literally striped with the gnawings of v/asps, which vre have v/atched at the work for hours together. (J. E.) [Different species of wasps use different materials for their nest. Vespa vulgaris always uses decayed wood, while V. germanica and other species use sound wood. Owing to the colour, the distinction between the nests of these insects is evident at a glance. The bundles of ligneous fibres thus detached are moistened before being used, with a glutinims liquid, which causes them to adhere together, and are then kneaded into a sort of paste, or papier maclie. The method employed by the wasp in making its nest has been so admirably described by Mr. S. Stone, that we cannot do better than copy his description, which aj^peared in " Beeton's Annual " of 1865. "* Keaiimur, vol. vi, bottom of pnge 182 ; Hist, of Selb. ii. 228 ; and 'ntrod. to Entomol, i. 504, 5th edition. Social-}Vcis2)s. 85 " Having found a place suitable — the deserted buiTows of the field-inico being pcrliajis more generally selected than any other by the underground species, the chamber formed by that animal for its nest being exactly the kind of place re- quired by the insect — it proceeds to attach its web to the centre of the roof of the chamber. This consists, in the first instance, of a pedicle, or footstalk, about half an inch in length, at the extremity of which a single cell is formed, which is presently surrounded by others. " Simultaneously with the formation of these cells, an um- brella-shaped covering is prepared above them. More cells are added, an egg being deposited in each of them as soon as formed, while constant additions are made to the covering until it has assumed a globular form, with only an aperture sufficiently large for the insect to pass in and out. Before the completion of the first covering, a second, just large enough to enclose it, is begun, and while this is in progress a thii'd is commenced, and then a fourth, and so on. When young wasps have been produced in suificient numbers to carry on the work without the assistance of the parent, an event which usually takes place in about six weeks from the commencement of the nest, she does not again leave home, but occupies herself solely in the task of dejjositiug eggs as fast as cells can be formed by the workers for their reception. " There are two methods by which the nests are enlarged by the workers after the queen has given up the task of building ; some species choosing one, some adopting the other. One consists in forming a series of regular sheets or layers, which are made to overlap each other like the slates or tiles on the roof of a building, in the same way as is pursued by the queen of every species so long as she continues to be the architect. When a few of these sheets have been com- pleted, that is, when they have been made to assume a spherical form, with only a small aperture for ingress and egress, each internal sheet is cut away, nearly but not quite, as fast as additional ones are formed externally, the shell or covering therefore slightly increasing in thickness as the nest increases in size. Thus architects among the human 86 Insect Architecture. race are careful to proportion the thickness, and consequently the strength of the walls to the magnitude of the building designed to be erected. " The other method consists in forming hollow pieces, or raising, as it were, blisters all over the plain surface which the queen has left ; and upon these other blisters, and so on continually ; cutting away, as in the former case, the under skin on the formation of the outer one. The latter method is adopted by the workers of V. crahro, V. vulgaris, and V. germanica; the former by V. Norvegica, V. sylvestris, V. rufa, and probably by V. arhorea. Cutting away the inner portions of the coverings is a necessary process in order to make room for the increased size of the comb or combs. The material cut away is not thi-owu by as useless, but is worked up afresh ; indeed this is effected in, and by, the very act of removing it ; it is then either used in enlarging the combs or it is brought out and employed in making additions to the outside. " As the nest increases in size, it is obvious that the cavity in which it is placed must be proportionably enlarged ; ac- cordingly, each wasp, as it emerges from the aperture, may be observed to bring out vrith it a small lump of earth which it has scraped from the walls of the chamber, care being taken to keep a clear space of about a quarter of an inch between the covering of the nest, and the walls of the chamber. About the same space also occurs between the combs, which are placed horizontally, with the mouth of the cells downwards ; supj)orting columns or pillars being con- structed at regular intervals so as to keep them at a proper distance apart, thus allowing the insects room to pass between them for the purpose of feeding the grubs. Support- ing columns or pillars are also placed between the roof of the chamber and the crown of the nest, connecting the one with the other ; and these supports are constantly strength- ened as the increasing weight of the nest renders such a precaution necessary. " The material of which the wasps' nests are composed is a sort of paper manufactured chiefly from wood by the insects Social- Wasps. 87 themselves ; one species using sound wood for the pur- pose, another that which has become decayed. This they scrape by means of their jaws from posts, rails, gates, hurdles, &c., in which act it becomes mixed with some peculiar fluid with which they are provided ; it then possesses nearly the same properties as the pulp from which paper is made, but is of fii'mer consistence. This is gathered in a small lump under the chest, to which it adheres, and in that way is carried to the nest. " The operators having, after the exhibition of a considerable amount of fickleness in the choice, fixed upon a suitable place for commencing, or recommencing operations — for these re- marks have reference to a nest ali'eady somewhat advanced in the building — place themselves along the edge of a yet unfinished piece, then walking slowly backward, spread the material as they go, along this edge, where it forms a thick streak ; they then go forward to the point at which they began to spread the composition, again marching slowly backward, press this streak between their jaws, which acts as a pair of jiincers, thus thinning it out throughout its whole length. They then go forward a second time, pressing it still thinner, and then a third, and so on, until they have rendered it sulficiently thin. Before this is accomplished, the operators have generally to go five or six times over their work. They do not return to the same spot with their next burden, but seek a fresh one, and thus allow the work they recently executed to become dry and fii"m, previous to making fm-ther additions to it. Possibly the material first ' used up ' was from wood of a dark colour ; the next may be from light- coloured wood, and the next from that of an inter- mediate colour ; and this it is which gives so much beauty to the coverings of the nests of these insects. " Vespa crahro and V. vulgaris are the only species which use decayed wood or touchwood in the fabrication of their nests ; the other species employ soimd wood, varied occasionally by sound vegetable fibre obtained from plants of different kinds. " From the upper combs in a nest, workers are produced ; 88 Insect Architecture. from the lower ones, queens or females ; and from tlie inter- mediate ones, males. Workers become developed early in the season, males not till an advanced period ; and young females or queens not until towards the close of the season. " The nests of V. crabro, V. vulgaris, and V. germanica, when of full size, measure not unfrequently twelve inches in diameter, the commtmities working on, in a favourable season, until the month of November ; while the laboiu's of the other species close, and the communities break uf) towards the end of August ; their nests scarcely attaining to half the size of those above mentioned." The accompanying illustration exhibits the nest of the common wasp in an early stage. The first cover has been Nest of Wasp in an early stage. completed, and a second is in course of progress. We have now before us a beautiful series of wasps' nests, in their various stages, prepared by Mr. Stone, in order to show the progressive enlargement of the edifice. First, there is the single cell attached to a small part that had penetrated the roof of the burrow. Next comes a more advanced stage, in which three cells are made, and the roof is just begun, being not quite half an inch in diameter. Then come five cells, and a tolerably large roof ; and then twelve cells, with a complete roof. The next stage is that which is represented in the illustra- tion, where the group of cells is seen suspended from its slender footstalk, and a second covering is in progress. By degrees the nest enlarges until the second layer or tier of Social- Wasps. 89 cells is begun, wliilc the fii-st tier is occupied in the centre by the pupa), sheltered by their little silk doors, and on the circumference by the larv;xi, whose cells are still open in order to allow themselves to be fed by the nui'se-wasps. Section of the same Nest, sliuwiiig the first tier of Cells. In these nests, the difference between the homes of Vespa vulgaris and those of V. (jermanica is very strongly marked, the former being yellowish brown, and the latter grey. One nest of V. germanica, is remarkable for being thickly studded with the long, white eggs of some insect, probably a parasite, which has gained admittance to the burrow, in spite of the care of its guardians. It may be here mentioned, that V. germanica is by far the most common species of wasp in England. The illustration at p. 90 represents a completed nest of V. germanica. The rough, thick covering is seen outside, and ■nithin are the tiers of cells, each layer being supported by pillars from the layer immediately above. These pillars are always formed, at the angle where these cells touch each other, so as to obtain as strong a foundation as possi- ble. Only a very small space is left between the combs, just enough room, in fact, for the nurse-wasps to pass as they feed the young. The reader will remember that the yoimg wasps all hang with their heads downwarels, being held in their places by a sort of ciasper at the end of the tail.] When the foundress-wasp has completed a certain number of cells, and deposited eggs in them, she soon intermits her 90 Insect Arcliitedure. building operations, in order to procure food for the young gruba, which now require all her care. In a few weeks these become perfect wasps, and lend their assistance in the extension of the edifice ; enlarging the original coping of the foundi-ess by side walls, and forming another platform of cells, suspended to the fii'st by columns, as that had been suspended to the ceiling. In this manner several platforms of combs are constructed, the outer walls being extended at the same time; and, by Section of the Social-Wasp's Nest. a a, the external wall ; 6, c c, five small terraces of cells for the neuter wasps , 'hich the colony consisted, either to add to the building or rei^au.- the damages which it had sustained. M. Eeaumur differs from oui- English naturalists, White, Social- Wasps. 93 and Kii'by and Spence, with respect to the materials em- ployed by the lioruct for building. The latter say that it employs decayed wood ; the former, that it uses the bark of the ash-tree, but takes less pains to split it into fine fibres than wasps do ; not, however, because it is destitute of skill ; for in constructing the suspensory columns of the platforms, a paste is prepared little inferior to that made by wasps. We cannot, from our own observations, decide which of the above statements is correct, as we have only once seen a liornet procuring materials, at Compton-Bassett, in Wiltshire ; and in that case it gnawed the inner bark of an elm which had been felled for several months, and was, consequently, dry and tough. Such materials as this would accoimt for the common yellowish-brown colour of a hornet's nest. (J. E.) [The accompanying figure represents a completed hornet's nest as it appears when suspended from a beam. Hornets 04 Insect Arcliitedure. often choose for their home the space between the roof and the ceiling of summer-houses, and the nests that are made in such localities are mostly large and handsome. The reader should notice the blisters by means of which the insect enlarges its habitation.] When hornets make choice of a tree for their domicile, they select one which is in a state of decay, and ali-eady partly hollowed ; but they possess the means, in their sharp and strong mandibles, of extending the excavation to suit their purposes ; and Reaumur frequently witnessed their operations in mining into a decayed tree, and carrying off what they had gnawed. He observed, also, that in such cases they did not make use of the large hole of the tree for an entrance, but went to the trouble of digging a gallery, sufficient for the passage of the largest hornet in the nest, through the living and undecayed portion of the ti-ee. As this is perforated in a winding direction, it is no doubt intended for the jiurpose of protecting the nest from the intrusion of depredators, who could more easily effect an entrance if there were not such a tortuous way to pass through. Jloriiel's Xc'Sl in a IkiIIow tree. [Here is an illustration of a hornet's nest as it appears in tlie hollow of a tree. Industrious as is this insect, it never takes needless trouble, and alters its nest according to circum- stances. As has already been seen, the combs are defended by a complete cover when the nest is placed in an open Social- Wasps. 95 situation. But wlien it is built in the hollow of a tree there is no cover at all, the insect evidently knowing that the wooden wall with which the cells are surrounded, afibrds a suffi- cient protection. In cases where a cover is made, the hornets do not form only a single entrance, as is the case with the wasp, but have a large number of small entrances in different parts of the wall. Some of these entrances can be seen in the illustration on page 93. Hornets are in one sense more industrious than wasps. When night falls, the wasps betake themselves to their home, and sleep throughout the night. But, if the moon be up, the hornet is sure to work throughout the entire night, and will often do so, even when no moon is visible.] One of the most remarkable of oiu" native social wasps is the tree-wasp (^Vesjm BrUannica), which is not imcommon in the northern, but is seldom to be met with in the southern parts of the island. Instead of burrowing in the ground like the common wasp ( Ves2m vulgaris), or in the hollows of trees like the hornet [Ves}!a crabro), it boldly swings its nest from the extremity of a branch, where it exhibits some resemblance, in size and colour, to a Welsh wig hung out to dry. We have seen more than one of these nests on the same tree, at Catrine, in Ayrshire, and at Wemyss Bay, in Eenfrewshirc. The tree which the Britannic wasp prefers is the silver fir, whose broad flat branch serves as a protection to the sus- pended nest both from the sun and the rain. We have also known a wasp's nest of this kind in a gooseberry-bush, at Red-house Castle, East Lothian. The materials and structure are nearly the same as those employed by the common wasp, and which we have ali'eady described. (J. E.) [ We have before us a beautiful example of a nest made by this species of wasp. There are no less than three consecutive coverings quite entire, while another is about three-fourths completed, and a fifth is just begun. The illustration exhibits a very perfect specimen ] A singular nest of a species of wasp is figured by Eoaumur, but is apparently rare in this country, as Kii-by and Spence 96 Insect Architecture. mention only a single nest of similar construction, foimcl in 11 garden at East-Dale. This nest is of a flattened globular figure, and composed of a great number of envelopes, so as to assume a considerable resemblance to a half-exj^anded Provence rose. The British specimen mentioned by Kirby and Spence had only one platform of cells ; Eeaumur had two ; but there was a large vacant space, which would probably have been filled with cells, had the nest not been taken away as a specimen. The whole nest was not much larger than a rose, and was composed of paper exactly similar to that emj)loyed by the common ground-wasj).* * 111 the IMag. of Nat. Hist. 1839, p. 458, Jlr. Shuckard gives an account of the nest of a wasp, wliich lie regards as Vespa Britannica, — remarkable for the material of whicli it was constructed, and for the locality in which it was found. This nest, which was exhibited at a meeting of the Entomological Society, was found near Croydon, built in a spariow's nest, and attached to the Social*Wasj)s. 97 [Tliis is probably tlie nest of V. ru/a. "VYo possess several specimens of tlie nest, one of wbicli oorrespouds tolerably closely ^\'itll the edifice described in the work.] There is another species of social-wasp (Epiponc nidulans, Late.) meriting attention from the singular construction of Wasp's Nest. its nest. It forms one or more terraces of cells, similar to those of the common wasp, but without the protection of an outer wall, and quite exposed to the weather. Swammerdam lining feathers. •' The smallness of the nest," says Mr. Shuckard, " and also of the tier of cells, as well as the peculiar material of which it appeared com- posed, led to a discussion, the tendency of which seemed to support the opinion that it was most probably the nest of a Polistcs, a social-wasp not yet found in this country, but if not of polistcs, certainly not yet determined or known." The nest was ovate, about an inch and a half long, with a tier of cells internally, originating from a common pedicle. It appeared to be constructed " of the agglutinated particles of a soft white wood, probably willow, very imperfectly triturated ;" whence it had exteinally a rough granulated appearance. It was sprinkled with black specks, arising perhaps from the intermixture of more decayed portions of the wood ; and was of a very fragile texture. " The nature of the material, and its unfinished execution, as well as the situation in which it was found, appear to me to be its own peculiarities, and I must necessarily consider it merely an accidental variation in material and locality from the usual nests of the Tespa Britcmnica of Leach." 98 Insect Architecture. foiincl a nest of this description attached to the stem of a nettle. Reaumur says that they are sometimes attached to the branch of a thorn or other shrub, or to stalks of grass; — peculiarities which prove that there are several species of these wasps. The most remarkable circumstance in the architecture of this species of vespiary is, that it is not horizontal, like those formerly described, but nearly vertical. The reason appears to be, that if it had been horizontal, the cells must have been frequently filled with rain , whereas, in the position in which it is placed, the rain runs off without lodging. It is, besides, invariably placed so as to face the north or the Wasps' Cells attached to a^ranch. east, and consequently is less exposed to rains, which most frequently come with southerly or westerly winds. It is another remarkable peculiarity, that, unlike the nests of other wasps, it is covered with a shining coat of varnish, to prevent moistui'e from soaking into the texture of the wasp's paper. The laying on this varnish, indeed, forms a con- siderable portion of the labour of the colony, and individuals Social- IVasjJS. 99 may be seen employed for hours together spreading it on with their tongues. jrhere is a genus of foreign liymenoptera, called Polistes, which is remarkable for the building powers possessed by its members. The accompanying illustration is taken from a nest in the British Museum, and is given of the natural size. The cells are not hexagonal, like those of the Ejjipone, but are roundish in form. Those in the centre assume a roughly -OOTb of Pulistes. hexagonal form by pressure, but those which form the circumference of the cell-group are nearly round, especially on their outer sides. The cells are not of uniform width, but are narrower at the base than at the mouth, thus causing the group to assume the form which is seen in the illustration. This curious group of cells was brought from Bareilly, in the East Indies, and in the same collectior there 100 Insect Architecture. are several other specimens, varying considerably both in shape aud size.] iTew circumstances are more striking, with regard to insects, as Kirby aud Speuce justly remark, than the great and incessant labour which maternal affection for their progeny leads them to imdergo. Some of these exertions are so dicprojiortionate to the size of the insect, that nothing short of ocular conviction could attribute them to such an agent. A wild bee, or a wasp, for instance, as we have seen, ■will dig a hole in a hard bank of earth some inches deep, and five or six times its own size, labouring unremittingly at this arduous task for several days in succession, and scarcely allowing itself a moment for eating or repose. It will then occupy as much time in searching for a store of food ; aud no sooner is this finished, than it will set about repeating the process, and, before it dies, will have completed five or six similar cells, or even more. We shall have occasion more particularly to dwell upon the geometrical arrangement of the cells, both of the wasp and of the social-bee, in our description of those interesting operations, which have long attracted the notice, and com- manded the admiration of mathematicians and naturalists. A few observations may here be properly bestowed upon the material with which the wasp-family construct the interior of their nests. The wasp is a paper-maker, and a most perfect and intelligent one. While mankind were arriving, by slow degrees, at the art of fabricating this valuable substance, the wasp was making it before their eyes, by very much the same process as that by which human hands now manufacture it with the best aid of chemistry and machinery. While some nations carved their records on wood, and stone, and brass, and leaden tablets, — others, more advanced, T\Tote with a style on wax, — others employed the inner bark of trees, and others the skins of animals rudely prepared, — the wasp was manufactm-ing a firm and durable paper. Even when the papyrus was rendered more fit, by a process of art, for the transmission of ideas in writing, the wasp was a better artisan Social- Wasps. 101 thau the Egyptians ; for the early attempts at paper-making were so rude, that the substance produced was ahnost useless, from being extremely friable. The paper of the papyrus was formed of the leaves of the plant, dried, pressed, and polished ; the wasp alone laiew how to reduce vegetable fibres to a pulp, and then unite them by a size or glue, spreading the substance out into a smooth and delicate leaf. This is exactly the process of paper-making. It would seem that the wasp knows, as the modern paper-makers now know, that the fibres of rags, whether linen or cotton, are not the only materials that can be used in the formation of jxapcr ; she employs other vegetable matters, converting them into a proper consistency by her assiduous exertions. In some respects she is more skiKul even than our pai^er-makers, for she takes care to retain her fibres of sufficient length, by which she renders her paper as strong as she requires. Many manufacturers of the present day cut their material into small bits, and thus produce a rotten article. One great distinction between good and bad paper is its toiighness ; and this difference is invariably produced by the fibre of which it is composed being long, and therefore tough ; or short, and therefore friable. The wasp has been labouring at her manufacture of paper from her first creation, with precisely the same instruments and the same materials ; and her success has been unvarying. Her machinery is very simple, and therefore it is never out of order. She learns nothing, and she forgets nothing. Men, from time to time, lose their excellence in particular arts, and they are slow in finding out real improvements. Such improvements are often the effect of accident. Paper is now manufactured very extensively by machinery in all its stages ; and thus, instead of a single sheet being made by hand, a stream of paper is poured out, which would form a roll large enough to extend round the globe, if such a length were desirable. The inventors of this machinery, Messrs. Fourdrinier, it is said, spent the enormous sum of 40,000Z. in vain attempts to render the machine capable of dctermiBing with precision the width of the roll ; and, at last, accom- 102 Insect Architecture. plished their object, at the suggestion of a bystander, by a sti-ap revolving upon an axis, at a cost of three shillings and sixpence. Such is the difference between the workings of human knowledge and experience, and those of animal instinct. We proceed slowly and in the dark, but our course is not bounded by a narrow line, for it seems difficult to say what is the perfection of any art ; animals go clearly to a given point — but they can go no further. We may, however, learn something fi-om their perfect knowledge of what is within their range. It is not improbable that if man had attended in an earlier state of society to the labours of wasps, he would have sooner known how to make pajier. We are still behind in our arts and sciences, because we have not always been observers. If we had watched the operations of insects, and the structure of insects in general, with more care, we might have been far advanced in the knowledge of many arts which are yet in their infancy, for nature has given us abundance of patterns. We have learnt to perfect some instruments of sound by examining the structure of the human ear ; and the mechanism of an eye has suggested some valuable improvements in achromatic glasses. Reaumur has given a very interesting account of the wasps of Cayenne (Ghartergus nidulans), ■which hang their nests in trees.* Like the bird of Africa called the social grosbeak (Loxia soda), they fabricate a perfect house, capable of con- taining many hundreds of their community, and suspend it on high out of the reach of attack. But the Cayenne wasp is a more expert artist than the bird. He is a pasteboard- maker ; — and the card with which he forms the exterior covering of his abode is so smooth, so strong, so uniform in its texture, and so white, that the most skilful manufacturer of this substance might be proud of the work. It takes ink admirably. The nest of the pasteboard-making wasp is impervious to water. It hangs upon the branch of a tree, as represented in the engraving ; and those rain-di'ops which penetrate through the leaves never rest upon its hard and polished * Memoires sur les Iiisectes, torn. vi.. mem. vii. See also Bonnet vol. ix. Social-Wasps. 103 surface. A small opening for the entrance of the insects terminates its fimnel-shaped bottom. It is impossible to unite more perfectly the qualities of lightness and strength. In the specimen from which we take our description, the length of which is nine inches, sis stout circular platforms stretch internally across, like so many floors, and fixed all round to the walls of the nest. They are smooth above, with hexagonal cells on the under surface. These plat- Nest of the Pastsboard-maker Wasp, with part removed to show the arrangement of the Cells. forms are not quite flat, but rather concave above, like a watch-glass reversed ; the centre of each platform is per- forated for the admission of the wasps, at the extremity of a short funnel- like projection, and through this access is gained from story to story. On each platform, therefore, can the wasps walk leisui-ely about attending to the pupae 104 Insect Architeciure. secui'ed in tlie cells, which, with the mouths downward, cover the ceiling above theii" heads — the height of the latter being just convenient for their work. [Unlike the habitations made by the British wasps, and which are vacated annually, this nest is permanent, and serves for several successive seasons. Of course, it must be enlarged continually, so as to accommodate an ever- increasing number of inhabitants. The mode of enlarging is sufficiently curious. The British wasps enlarge their nests either by making a larger covering and then removing tlie smaller, or by raising blisters on the outside, and eating away beneath them. But the pendulous wasp of Brazil pro- ceeds on just the opposite principle, making new cells first, and covering them afterwards. The new tier of cells is set on the bottom of the nest, which thus becomes the floor of that tier, and a new bottom is then made beneath these new cells.] Pendent wasps' nests of enormous size are found in Ceylon, suspended often in the talipot-tree at the height of seventy feet. The appearance of these nests thus elevated, with the larger leaves of the tree, used by the natives as umbrellas and tents, waving over them, is very singular. Though no species of European wasp is a storer of honey, yet this rule does not apply to certain species of South America. In the ' Annals and Magazine of Natural History ' for June, 1841, will be found a detailed account, with a figure, of the pendent nest of a species termed by Mr. A. White Myrapetra saitel- laris. The external case consists of stout cardboard covered with conical knobs of various sizes. The entrances are artfully protected by pent-roofs from the weather and heavy rains ; and are tortuous, so as to render the ingress of a moth or other large insect difficult. Internally are fourteen combs, exclusive of a globular mass, the nucleus of several circular combs, which are succeeded by others of an arched form — that is, constituting segments of circles. Many of the uppermost combs were found to have the cells filled with honey of a brownish-red colour, but which had lost its flavour. After entering into some miniite details, Mr. A. Social-Wasjis. 105 Wlilte makes the following interesting observations : — " Azara, in the account of his residence in various parts of South America, mentions the fact of several icasjjs of these countries collecting honey. The Baron Walchenaer, who edited the French translation of this work, published in 1809, thought that the Spanish traveller, who was unskilled in entomology, had made some mistake with regard to the insects, and regarded the so-called irasjjs as belonging to Nest of Myrapetra. some bee of the genus of which Ajns amaltliea is the type {Melipona). Latreille (who afterwards corrected his mistake) also believed that they must be referred to the genera Melipona or Trigona — insects which in South America take the place of our honey-bee. These authors were afterwards clearly convinced of the correctness of Azara's observations, by the circumstance of M. Auguste do St. Hilaire finding near the river Uruguay an oval grey-coloured nest of a 106 Insect Architecture. papery consistence, like that of the European wasps, sus- pended from the branches of a small shi'ub about a foot from the ground : he and two other attendants partook of some honey (contained in its cells) and found it of an agreeable sweetness, free from the j)harmaceutic taste which so fre- quently accompanies European honey. He gives a detailed account of its poisonous effects on himself and his two men. Afterwards he procured specimens of the wasp, which was de- scribed by Latreille under the name of Polistes Lechegumia." [The accompanying illustration shows this remarkable nest, both as it appears externally, and when divided vertically. The material is probably the dung of the Capincha, an animal allied to the guinea-pig and the agouti. The natives, at all events, state that such is the case, and the aspect of the nest as seen through a magnifying glass carries out this assertion. The nest is hung to a branch, and is seldom more than four feet from the groimd. The insect is a very little one in comparison with the size of the nest, which is sixteen inches in length, and twelve in width. The largest speci- mens of this insect are only one third of an inch long, while the generality scarcely exceed a quarter of an inch. Its coloui' is brown. In the section is shown the very peculiar shape of the combs. At the upper part is seen the globular centre, sur- rounded with a comb that completely encircles it. Other combs follow in order, but are less curved as they approach the bottom of the nest. The insects obtain admission to the several tiers by means of apertures which are left between the extremities of the comb and the wall of the nest. The combs are made of the same material as the outer wall, but are very thin and paper-like. This nest may be seen in the British Museum,] It would seem that the nest described by Mr. White agrees with that of a wasp termed Chiguana by Azara (or Lecliegiiana), and is very different to the slight papery nest of the Polistes Lecliegiiana of Latreille. We may add that M. Auguste de St. Hilaire speaks of two species of wasps remarkable for storing honey in South America ; the honey Social- Wasps- 107 of one is white, of the other reddish. That the habits of these honey-wasps must differ considerably from those of any of our European species we may at once admit ; perhaps in some points of their economy these insects may approach the bee. [In the same country as is inhabited by the Myrapetra, and in much the same localities, is sometimes found the nest of another honey-making wasp, called Nedarima analis, a small and i)lainly-clad insect. It is hung to the branches of low trees and underwood, and often includes both twigs and leaves in its structure. The combs of this insect are greatly curved, in order to suit the shape of the general covering, but are not arranged \^-ith that beautiful regularity which dis- tinguishes those of the Myrapetra. A specimen of this nest may be seen in the British Museum, and as the outer covering has been partially taken away, the observer will be enabled to note the general form of the combs and the structure of the cells. In the accompanying illustration are shown the habitations of two remarkable insects, both belonging to the Hymenoptera. Indeed, the gi-eater number of pensile nests made by insects are formed by members of this important order ; and, if we were to exclude all the wasps, bees, and ants, we should find that we had excluded about ninety per cent, of the pensile architects. The left-hand figui-e represents a nest made by a species of Polyhia, inhabiting Brazil. It is made of a papery kind of substance, of rather slight texture, and is fixed to the stalk of a reed. The outside of the nest is seen to be marked with a series of horizontal ribs. These show the progressive stages of the nest, each rib marking a layer of paper as it was spread by the insect builder. The combs extend thi-oughout the entire nest, the largest occupying the centre, and the smallest the ends. Each comb is fii-mly supported by a foot- stalk, which is fixed, not to the upper tier of cells, as is the case with the British wasps, but to the reed on which the nest is built. Other s])ocies of Polyhia build nests different in shape and 108 Insect Architecture. arrangement, thougli still of the pensile character. One species builds a nearly globular nest, made in a rather curious manner. Carrying out still farther the principle on which Xesfs of Polybia. the cardboard wasp enlarges its nest, the Polybia entirely covers the outer wall with cells, and then makes a new wall over them. When a nest has reached a tolerable size, it is composed of a whole series of concentric combs, the roof of each having been originally the outer wall of the nest. There are in the British Museum some admirable specimens of these nests, in some of which the process of enlargement can be very clearly traced. Patches of new cells are seen upon the external covering, while a few breaches in the structure show the concentric combs. One very curious point about these cells is, that they are not uniform in their direction, as is generally the case with 8ocial*V/asps. 109 those of social liymenoptera. Tlic greater i^art, siicli as the various wasps, hornets, aud their kin, have the mouths of tho cells downwards, while the cells of the hive-bee are nearly horizontal. But the cells of this insect arc arranged without the least regard to their position, all the bases pointing towards the centre of the nest, aud all the mouths radiating outwards. Nests of Sj'DKca and Polybia. There seems to be scarcely any bound to the variety which exists in the nests of the social hymenoptera. The insect which makes the nest which is represented in the illustration is a native of Brazil, and is known to entomo- logists as Synceca cyanea. The first of these names is given to it on account of its social habits, and the second, in reference to the bluish colour of its body. It is rather larger than the preceding insects, being about three quarters of an inch in length. Its wings are brown. 110 Insect Architecture. The shape and size of the nest are exceedingly variable, but it is almost invariably longer than wide, and is fixed to a branch or some similar object. Sometimes it attains con- siderable dimensions, and has been known to measure a full yard in length. Yet, however large it may be, there is only a single comb, which is set upon the side of the nest next the branch, and, in consequence, has almost all its cells placed in a horizontal direction. In the illustration, the right-hand figure represents the external apjiearance of the nest, and the central figure shows the manner in which the single comb is set upon the branch. The nest which occupies the left hand of the illustration is made by a sjjecies of Polybia, and is here given in order to show a remarkable example of similarity in the mode of building adopted by two difierent insects. In the one case, however, the cells are all fastened by their bases to the branch, but in the other the cells are attached to one common base which is prolonged into a footstalk. There have been lately discovered some very remarkable social nests. Specimens of both these nests may be seen in the entomological department of the museum at Oxford. The first is formed very much like a rather flattened Florence flask, and is hung by the neck from the branch of a tree. It is made of a strong, parchment -like substance, formed by innumerable silken threads woven and matted together into a kind of felt. When it was cut open a most singular sight was exhibited. Nearly the whole of the interior was covered with the pupas of some butterfly, all hanging by their tails, and many of them susj)ended to a twig which projected downwards into the nest. Although the nest is barely eight inches in length, a great proportion of which is taken up by the neck, about one hundred pupas were found in it. At the bottom of the nest is a small and yearly circular aperture, through which the insects could make their way as soon as they escaped from the pupal envelope, and before their wings became extended and hardened. The butterfly which makes this singular nest is a native of Mexico, and is named Eucheira socialis. The colour of its Soeial^Wasps. 1 1 1 wings is dark browTi, -with an ill-defined white band across them. The second nest was brought from tropical Africa, and is remarkable for another peculiarity. It is shaped much like a cushion, and its measurements are, eight inches in length, five and a half in breadth, and three in dei)th. Instead of having only one place of exit for the inmates, it has thirteen or fourteen, all formed in the same manner. A number of short, stifl', and almost bristly threads are set round the apertures, their ends all projecting outwards, and converging to a point, where they all meet and even slightly cross each other. Owing to this structure, it is easy enough for any of the insects to pass out, as the converging hairs yield to the pressure, whereas they form an efiectual barrier against any insect that wishes to creep into the nest. The material of the nest is very strong and hard, and is fonned of two layers, the inner being made of smooth brown silk, and the outer of harsher and stronger orange silk threads.] 112 Insect Architecture. CEAPTEB V. ARCHITECTURE OF THE HIVE-BEE. A LTHOUGH the hive-bee {Apis melUfica) has engager! the -^ attention of the curious from the earliest ages, recent discoveries prove that we are yet only beginning to arrive at a correct knowledge of its wonderful proceedings. Pliny informs us that Astromachus, of Soles, in Cilicia, devoted fifty-eight years to the study ; and that Philiscus the Thracian spent his whole life in forests for the purpose of Part of a Honeycomb, and Bees at work. observing them. But in consequence (as we may naturally infer) of the imperfect methods of research, assuming that what they did discover was known to Aristotle, Columella, and Pliny, we are justified in pronouncing the statements of these philosophers, as well as the embellished poetical pictures of Yirgil, to be nothing more than conjecture, almost in every particular erroneous. It was not indeed Hive-fBees. 113 till 1711, when glass liives were invented by Maraldi, a mathematician of Nice, that what we may call the in-door proceedings of bees could bo observed. This important invention was soon afterwards taken advantage of by M. Eeaumiir, who laid the foundation of the more recent discoveries of John Hunter. Schirach, and the Hubers. The admirable architecture which bees exhibit in their miniatm-e cities has, by these and other naturalists, been investigated with great care and accuracy. We shall en- deavour to give as full an account of the wonderful structures as our limits will allow. In this we shall chiefly follow M. Huber the elder, whose researches appear almost mira- culous when we consider that he was blind. At the early age of seventeen this remarkable man lost his sight by gutta screna, the " di'op serene " of our own Milton. But though cut off from the sight of Nature's works, he dedicated himself to their study. He saw them through the eyes of the admirable woman whom he married ; his philosophical reasonings pointed out to her all that he wanted to ascertain ; and as she reported to him from time to time the results of his ingenious experiments, he was enabled to complete, by diligent investigation, one of the most accm'ate and satisfactory accounts of the habits of bees which had ever been produced. It had long been known that the bees of a hive consist of thi'ee sorts, which was ascertained by M. Eeaumur to be distinguished as workers or neuters, constituting the bulk of the population ; drones or males, the least numerous class ; and a single female, the queen and mother of the colony. Schirach subsequently discovered the very extraordinary fact, which Huber and others have proved beyond doubt, that when a hive is accidentally deprived of a queen, the grub of a worker can be and is fed in a particular manner so as to become a queen and supply the loss.* But another * It is right to remark that Huish and others have suggested that the gi-ubs thus royalized may originally be misplaced queens ; yet this admission is not necessary, since Madlle. Jurine has proved, by dissection, the workers to be imperfect females. Z 114 Insect Architecture. discovery of M. Huber is of more importance to the subject of architecture now before us. By minute research he ascertained that the workers which had been considered by former naturalists to be all alike, are divided into two important classes, nurse-bees and wax-makers. The nurse-hees are rather smaller than the wax-workers, and even when gorged with honey their belly does not, as in the others, aj)pear distended. Their business is to collect honey, and impart it to their companions ; to feed and take care of the young grubs, and to complete the combs and cells which have been founded by the others ; but they are not charged with provisioning the hive. The ivax-worhers, on the other hand, are not only a little larger, but their stomach, when gorged with honey, is capable of considerable distension, as M. Huber proved by relocated experiments. He also ascertained that neither of the varieties can alone fulfil all the functions shared among the workers of a hive. He painted those of each class with different colours, in order to study their proceedings, and their labours were not interchanged. In another experi- ment, after supplying a hive deprived of a queen with brood and pollen, he saw the nui'se-bees quickly occxipied in the nutrition of the grubs, while those of the wax-working class neglected them. When hives are full of combs, the wax- workers disgorge their honey into the ordinary magazines, making no wax ; but if they want a reservoir for its recep- tion, and if their queen does not find cells ready made wherein to lay her eggs, they retain the honey in the stomach, and in twenty-four hours they produce wax. Then the labour of constructing combs begins. It might perhaps be supposed that, when the country does not afford honey, the wax-workers consume the provi- sion stored up in the hive. But they are not permitted to touch it. A portion of honey is carefully preserved, and the cells containing it are protected by a waxen covering, which is never removed except in case of extreme necessity, and when honey is not to be otherwise procured. The cells are at no time opened dui-ing summer ; other reservoirs, Hive-Bees. 115 always exposed, contribute to the daily use of the com- luimity ; each bee, however, supplying itself from them with nothing but what is required for present w'auts. Wax- workers api)ear with large bellies at the entrance of their hive only when the country affords a copious collection of honey. From this it may be concluded that the production of the waxy matter depends on a concurrence of circum- stances not invariably subsisting. Nm-se-bees also produce wax, but in a very inferior quantity to w'hat is elaborated by the real wax-workers. Another characteristic whereby an attentive obsei-ver can determine the moment of bees collecting sufficient honey to produce wax, is the strong odour of both these substances from the hive, which is not equally intense at any other time. From such data, it was easy for M. Huber to discover whether the bees worked in w'ax in his own hives, and in those of the other cultivators of the district. There is still another sort of bee, first observed by Huber in 1809, which ajspear to be only casual inmates of the hive, and which are di-iven forth to starve, or are killed in conflict. They closely resemble the ordinary workers, but are less hairy, and of a much darker colour. These have been called black bees, and are supposed by Huber to be defective bees;* but Kirby and Spence conjecture that they are toil-worn superannuated workers, of no further use, and are therefore sacrificed, because bm-densome to a community which tolerates no unnecessary inmates. Preparation of Wax. In order to build the beautiful combs, which every one must have repeatedly seen and admired, it is indispensable that the architect-bees should be jirovided with the materials — with the wax, in short, of which they are principally formed. Before we follow them, therefore, to the operation of build- ing, it may be necessary to inquire how the wax itself is * Huber on Bees, p. 338. 116 Insect Architecture. procured. Here the discoveries of recent inquirers have been little less singular and unexpected than in other departments of the history of these extraordinary insects. Now that it has been proved that wax is secreted by bees, it is not a little amusing to read the accounts given by our elder naturalists, of its being collected from flowers. Our countryman, Thorley,* appears to have been the first who suspected the true origin of wax, and Wildman (1769) seems also to have been aware of it ; but Reaumur, and particularly Bonnet, though both of them in general shrewd and accurate observers, were partially deceived by appearances. The bees, we are erroneously told, search for wax ""upon all sorts of trees and plants, but especially the rocket, the simple poppy, and in general all kinds of flowers. They amass it with their hair, with which their whole body is invested. It is something pleasant to see them roll in the yellow dust which falls from the chives to the bottom of the flowers, and then return covered with the same grains ; but their best method of gathering the wax, especially when it is not very plentiful . is to carry away all the little particles of it with their jaws and fore feet, to press the wax upon them into little pellets, and slide them one at a time, with their middle feet, into a socket or cavity, that opens at their hinder feet, and serves to keep the burthen fixed and steady till they return home. They are sometimes exposed to incon- veniences in this work by the motion of the air, and the delicate texture of the flowers, which bend under their feet and hinder them from packing up their booty, on which occasions they fix themselves in some steady place, where they press the wax into a mass, and wind it round their legs, making frequent returns to tie flowers; and when they have stocked themselves with a sufficient quantity, they immediately repair to their habitation. Two men, in the compass of a whole day, could not amass so much as two little balls of wax ; and yet they are no more than the com- mon burthen of a single bee, and the produce of one journey. Those who are employed in collecting the wax from flowers * Melisselogia, or Female Monarchy, 8vo., Lond. 1744, Hive-Bees. 117 are assisted by their companions, who attend them at the door of the hive, case them of their load at their arrival, brush their feet, and shake out the two balls of wax ; upon which the others return to the fields to gather new treasure, while those who disbui'thoned them convey their charge to the magazine. But some bees, again, when they have broiight their load home, carry it themselves to the lodge, and there deliver it, laying hold of one end by their hinder feet, and viiih their middle feet sliding it out of the cavity that con- tained it ; but this is evidently a work of supererogation which they are not obliged to perform. The packets of wax continue a few moments in the lodge, till a set of officers come, who are charged with a third commission, which is to kuead this wax with their feet, and sj)read it out into different sheets, laid one above another. This is the tmwrought wax, which is easily distinguished to be the produce of different flowers, by the variety of colours that appear on each sheet. When they afterwards come to work, they knead it over again ; they piu'ify and whiten, and then reduce it to a uniform colour. They use this wax with a wonderful fru- gality ; for it is easy to observe that the whole family is con- ducted by prudence, and all their actions regulated by good government. Everything is granted to necessity, but nothing to superfluity ; not the least grain of wax is neglected, and if they waste it, they are frequently obliged to provide more ; at those very times when they want to get their provision of honey, they take off the wax that closed the cells, and carry it to the magazine."* Eeavunur hesitated in believing that this was a correct view of the subject, from observing the great difference between wax and pollen ; but he was incKned to think the pollen might be swallowed, partially digested, and disgorged in the form of a kind of paste. Schirach also mentions, that it was remarked by a certain Lusatian, that wax comes from the rings of the body, because, on withdrawing a bee while it is at work, and extending its body, the wax may be seen there in the form of scales. * De la Pliche, Sp-xtacle de la Nature, vol. i. 118 Insect Architecture. The celebrated John Hunter shrewdly remarked that the pellets of pollen seen on the thighs of bees are of diflfereut colours on different bees, while the shade of the new-made comb is always uniform ; and therefore he concluded that pollen was not the origin of wax. Pollen also, he observed, is collected with greater avidity for old hives, where the comb is complete, than for those where it is only begun, which would hardly be the case were it the material of wax. He found that when the weather was cold and wet in June, so that a young swarm was prevented from going abroad, as much comb was constructed as had been made in an equal time when the weather was favourable and fine. The pellets of pollen on the thighs being thence proved not to be wax, he came to the conclusion that it was an external secretion, originating between the plates of the belly. When he first observed this, he felt not a little embarrassed to explain the phenomenon, and doubted whether new plates were forming, or whether bees cast their old ones as lobsters do their shell. By melting the scales, he ascertained at least that they were wax ; and his opinion was coniii'med by the fact, that the scales are only to be found during the season when the combs are constructed. But he did not succeed in completing the discovery by observing the bees actually detach the scales, though he conjectured they might be taken uj) by others, if they were once shaken out from between the rings. * We need not be so much surprised at mistakes committed upon this subject, when we recollect that honey itself was believed by the ancients to be an emanation of the air — a dew that descended upon flowers, as if it had a limited commission to fall only on them. The exposm-e and correction of error is one of the first steps to genuine knowledge ; and when we are aware of the stumbling-blocks which have interrupted the progress of others, wo can always travel more securely in the way of truth. That wax is secreted is proved both by the wax -pouches * Philosophical Trans, for 1792, p. 14".. Hive-Bees. 119 within tlie rings of tLio abdomen, and by actual experiment. Hubcr and others fed bees entirely upon honey or sugar, and, notwithstanding, wax was prodiiced and combs formed as if they had been at liberty to select their food. "When bees were confined," says M. Huber, " for the purpose of discover- ing whether honey was sufficient for the production of wax, they sujiported their captivity patiently, and showed uncom- mon perseverance in rebuilding their combs as we removed them. Oiu' experiments required the presence of grubs ; honey and water had to be provided ; the bees were to bo supplied with combs containing brood, and at the same time it was necessary to confine them, that they might not seek pollen abroad. Having a swarm by chance, which had be- come useless from sterility of the queen, we devoted it for our investigation in one of my leaf-hives, which was glazed on both sides. We removed the queen, and substituted combs containing eggs and young grubs, but no cell with farina ; even the smallest particle of the substance which John Hunter conjectm-ed to be the basis of the nutriment of the young was taken away. " Nothing remarkable occiu'red during the first and second day : the bees brooded over the young, and seemed to take an interest in them ; but at sunset on the third a loud noise was heard in the hive. Impatient to discover the reason, we opened a shutter, and saw all in confusion; the brood was abandoned, the workers ran in disorder over the combs, thousands rushed towards the lower part of the hive, and those about the entrance gnawed at its grating. Their design was not equivocal ; they wished to quit their prison. Some imperious necessity evidently obliged them to seek elsewhere what they could not find in the hive ; and apprehen- sive that they might perish if I restrained them longer from yielding to their instinct, I set them at liberty. The whole swarm escaped, but the hour being unfavourable for their collections, they flew around the hive, and did not depart far from it. Increasing darkness and the coolness of the air compelled them very soon to return. Probably these cir- cumstances calmed their agitation ; for we observed them 120 Insect Architecture, peaceably remouuting their combs ; order seemed re-esta- blislied, and we took advantage of this moment to close the hive. " Next day, the 19th of July, we saw the rudiments of two royal cells, which the bees had formed on one of the brood- combs. This evening, at the same hour as on the preceding, we again heard a loud buzzing in the closed hive ; agitation and disorder rose to the highest degree, and we were again obliged to let the swarm escape. The bees did not remain long absent from their habitation ; they quieted and retiu-ned as before. We remarked on the 20th that the royal cells had not been continxied, as would have been the case in the ordinai'y state of tilings. A gi-eat tumult took place in the evening ; the bees appeared to be in a delirium ; we set them at liberty, and order was restored on their return. Their captivity having endured five days, we thought it needless to protract it farther ; besides, we were desirous of knowing whether the brood was in a suitable condition, and if it had made the usual progres^; and we vrished also to try to discover what might be the cause of the periodical agitation of the bees. M. Burnens (the assistant of Huber), having exposed the two brood-combs, the royal cells were imme- diately recognised ; but it was obvious that they had not been enlarged. Why should they ? Neither eggs, grubs, nor that kind of paste peculiar to the individuals of their species were there ! The other cells were vacant likewise ; no brood, not an atom of paste, was in them. Thus, the worms had died of hunger. Had we precluded the bees from all means of sus- tenance by removing the farina? To decide this point, it was necessary to confide other brood to the care of the same insects, now giving them abundance of pollen. They had not been enabled to make any collections while we examined their combs. On this occasion they escaped in an apartment where the windows were shut ; and after substituting young worms for those they had allowed to perish, we returned them to their prison. Next day we remarked that they had resumed courage ; they had consolidated the combs, and remained on the brood. They were then provided with Hive-Bees. 121 fragments of combs, wliere other workers liad stored up fariua ; and to be able to observe what they did with it, we took this substance from some of their cells, and spread it on the board of the hive. The bees soon discovered both the fiirina in the combs and what we had exposed to them. They crowded to the cells, and also descending to the bottom of the hives, took the pollen grain by grain in their teeth, and conveyed it to their mouths. Those that had eaten it most greedily mounted the combs before the rest, and stopping on the cells of the young worms, inserted their heads, and remained there for a certain time. M. Burnens ojjened one of the divisions of the hive gently, and powdered the workers, for the purpose of recognising them when they should ascend the combs. He observed them during several hours, and by this means ascertained that they took so great a qiiantity of pollen only to impart it to their youiig. Then withdrawing the portions of comb which had been placed by us on the board of the hive, we saw that the pollen had been sensibly diminished in quantity. They were returned to the bees, to augment their provision still fui'ther, for the purpose of extending the experiment. The royal, as well as several common, cells were soon closed ; and, on opening the hive, all the worms were foimd to have prospered. Some still had their food before them ; the cells of others that had spun were shut with a waxen covering. "We witnessed these facts repeatedly, and always with equal interest. They so decisively prove the regard of the bees towards the grubs which they are intrusted with rearing, that we shall not seek for any other explanation of their conduct. Another fact, no less extraordinary, and much more difficult to be accounted for, was exhibited by bees constrained to work in wax, several times successively, from the Syrup of sugar. Towards the close of the experiment they ceased to feed the young, though in the beginning these had received the usual attention. They even frequently dragged them from theii" cells, and carried them out of the hive."* Mr. Wiston, of GermantowTi, in the United States, mentions * Huber on Bees. 122 Insect Archiiedure. a fact conclusive on this subject. " I had," says he, " a late swarm last summer, which, in consequence of the drought, filled only one box with honey. As it was late in the season, and the food collected would not enable the bees to subsist for the winter, I -shut up the hive, and gave them half-a-pint of honey every day. They immediately set to work, filled the empty cells, and then constructed new cells enough to fill another bos, in which they deposited the remainder of the honey." A more interesting proof is thus related by the same gentleman: "In the summer of 1824,1 traced some wild bees, which had been feeding on the flowers in my meadow, to their home in the woods, and which I found in the body of an oak-tree, exactly fifty feet above the ground. Having caused the entrance to the hive to be closed by an expert climber, the limbs were separated in detail, until the trunk alone was left standing. To the upper extremity of this, a tackle-fall was attached so as to connect it with an adjacent tree, and, a saw being applied below, the naked trunk was cut through. When the immense weight was lowered nearly to the earth, the ropes broke, and the mass fell with a violent crash. The part of the tree which con- tained the hive, separated by the saw, was conveyed to my garden, and placed in a vertical position. On being released, the bees issued out by thousands, and though alarmed, soon became reconciled to the change of situation. By removing a part of the top of the block the interior of the hive was exposed to view, and the comb itself, nearly six feet in height, was observed to have fallen down two feet below the roof of the cavity. To repair the damage was the first object of the labourers : in doing which, a large part of their store of honey was expended, because it was at too late a season to obtain materials from abroad. In the following February these industrious but unfortunate insects issuing in a confused manner from the hive, fell dead in thousands around its entrance, the victims of a poverty created by their efforts to repair the ruins of their habitation."* * American Quarterly Review for June, 1828, p. 382. EiveSees. 123 In another experiment, M. Hubor confined a swarm so that they had access to nothing beside honey, and five times successively removed the combs with the precaution of pre- venting the escape of the bees from the apartment. On each occasion they produced new combs, which puts it beyond dispute that honey is sufficient to effect the secretion of wax without the aid of pollen. Instead of supplying the bees with honey, they were subsequently fed, exclusively, on pollen and fruit ; but though they were kept in captivity for eight days under a bell-glass, with a comb containing nothing but farina, they neither made wax nor was any secreted under the rings. In another s-erics of experiments, in which bees were fed with different sorts of sugar, it was found that nearly one-sixth of the sugar was converted into wax, dark- coloured sugar yielding more than double the quantity of refined sugar. It may not be out of place to subjoin the few anatomical and physiological facts which have been ascertained by Huber, Maddle. Jurine, and Latreille. The first stomach of the worker-bee, according to Latreille,* AVoiker-bee, magnified — sboning the position of the scales of Wax. is appropriated to the reception of honey, but this is never fomid in the second stomach, which is surrounded with mus- * Liitreille, Jle'm. Acad, des liciences, 1821. 124 Insect Architecture. cular rings, and from one end to tlie other very mucli re- sembles a cask covered with hoops. It is within these rings that the wax is produced ; but the secreting vessels for this purpose have hitherto escaped the researches of the acutest naturalists. Huber, however, plausibly enough conjectures that they are contained in the internal lining of the wax- pockets, which consists of a cellular substance reticulated with hexagons. The wax-pockets themselves, which are concealed by the overlapping of the rings, may be seen by pressing the abdomen of a worker-bee so as to lengthen it, and separate the rings further from each other. When this Abdomen of Was-workor I!ee. has been done, there may be seen on each of the four inter- mediate hoops of the belly, and separated by what may be called the keel (carina), two whitish-coloured pouches, of a soft texture, and in the form of a trapezium. Within, the little jjlates or scales of wax are produced from time to time, and are removed and employed as we shall presently see. We may remark, that it is chiefly the wax-workers which produce the wax ; for though the nurse-bees are furnished with wax-pockets, they secrete it ordy in very small quan- tities ; while in the queen-bee, and the males or drones, no pockets are discoverable. Hive-Bees. 125 '* All the scales," says Hiiber, " are not alike iu every bee, for a diflference is perceptible in consistence, shape, and thickness ; some are so thin and transparent as to require a magnifier to be recognised, or we have been able to dis- cover nothing but spiculas similar to those of water freezing. Neither the spiculse nor the scales rest immediately on the membrane of the pocket, a slight liquid medium is inter- posed, serving to lubricate the joinings of the rings, or to render the extraction of the scales easier, as otherwise the/ might adhere too fii-mly to the sides of the pockets." M. Huber has seen the scales so large as to project beyond the rings, being visible without stretching the segments, and of a whitish yellow, from greater thickness lessening their transparency. These shades of difference in the scales of various bees, their enlarged dimensions, the fluid interposed beneath them, the correspondence between the scale and the size and form of the pockets, seem to infer the oozing of this substance through the membranes whereon it is moulded. He was confii'med in this opinion by the escape of a trans- parent fluid on piercing the membrane, whose internal sur- face seemed to be applied to the soft parts of the belly. This he found coagulated in cooling, when it resembled wax, and again liquefied on exposure to heat. The scales themselves, also, melted and coagulated like wax.* By chemical analysis, however, it appears that the wax of the rings is a more simple substance than that which composes the cells ; for the latter is soluble in ether, and in spirit of turpentine, while the former is insoluble in ether, and but partially soluble in spirit of turpentine. It should seem to follow, that if the substance found lying under the rings be really the elements of wax, it undergoes some subsequent preparation after it is detached ; and that the bees, in short, are capable of impregnating it with matter, impai'ting to it whiteness and ductility, whereas in its un- prepared state it is only fusible. * Ruber on Bees, p. 325. 126 Insect Architecture. Propolis. Wax is not the only material employed by bees in their architecture. Beside this, they make use of a brown, odo- riferous, resinous substance, called propolis* more tenacious and extensible than wax, and well adapted for cementing and varnishing. It was strongly suspected by Keaumur that the bees collected the propolis from those trees which are known to produce a similar gummy resin, such as the poplar, the birch, and the willow ; but he was thi-own into doubt by not being able to detect the bees in the act of procuring it, and by observing them to collect it where none of those trees, nor any other of the same description, grew. His bees also refused to make use of bitiimen, and other resinous sub- stances, with which he supplied them, though Mr. Knight, as we shall afterwards see, was more successful .f Long before the time of Keaumur, however, Mouffet, in his Insedarum Tlieatrum, quotes Cordus for the opinion that proj)olis is collected from the buds of trees, such as the poplar and birch ; and Eeim says it is collected from the pine and fir. % Huber at length set the question at rest ; and his experiments and observations are so interesting, that we shall give them in his own words : — ■ " For many years," says he, " I had fruitlessly endeavoured to find them on trees producing an analogous substance, though multitudes had been seen returning laden with it. " In July, some branches of the wild poplar, which had been cut since spring, with very large buds, full of a reddish, viscous, odoriferous matter, were brought to me, and I planted them in vessels before hives, in the way of the bees going out to forage, so that they could not be insensible of their presence. Within a quarter of an hour, they were visited by a bee, which separating the sheath of a bud with its teeth, * From two Greek words irpo iroKis meiining before the city, as the sub- stance is principally applied to the projecting parts of the hive, t Phil. Trans, for 1807, p. 242. X Schirach, Hist, des Abeilles, p. 241. Eive-Bees. 127 di'cw out threads of tlic viscous substance, and lodged a pellet of it in one of the baskets of its limbs ; from another bud it collected another pellet for the opposite limb, and departed to the hive. A second bee took the place of the former in a few minutes, following the same procedure. Young shoots of poplar, recently cut, did not seem to attract these insects, as their viscous matter had less consistence than the former.* " Different experiments proved the identity of this sub- stance with the propolis ; and now, having only to discover how the bees applied it to use, we peoj)led a hive, so prepared as to fulfil our views. The bees, building upwards, soon reached the glass above ; but, imable to quit their habita- tion, on account of rain, they were three weeks without bringing home propolis. Their combs remained perfectly white until the beginning of July, when the state of the atmosphere became more favourable for our observations. Serene, warm weather engaged them to forage, and they retui'ued from the fields laden with a resinous gum, re- sembling a transparent jelly, and having the colour and lustre of the garnet. It was easily distinguished from the farinaceous pellets then collected by other bees. The M'orkers bearing the propolis ran over the clusters, sus- pended from the roof of the hive, and rested on the rods supporting the combs, or sometimes stopped on the sides of their dwelling, in expectation of their companions coming to disencumber them of their biu'then. We actually saw two or thi-ee arrive, and cai-ry the propolis from off the limbs of each with their teeth. The upper part of the hive exhibited the most animated spectacle ; thither a multitude of bees resorted from all quarters, to engage in the pre- dominant occupation of the collection, distribution, and ap- plication of the propolis. Some conveyed that of which they had unloaded the purveyors in their teeth, and deposited it in heaps; others hastened, before its hardening, to sjjread it out like a varnish, or formed it into strings, proijortioned to the interstices of the sides of the hives to be filled up. * Kirby and Spence observed bees very busy in collecting propolis from the tacamahaca-tree {Fojmlus balsamifera). — Introd., ii. 186. 128 Insect Architecture. Nothing could be more diversified tlian the operations carried on. " The bees, apparently charged with applying the pro- polis within the cells, were easily distinguished from the multitude of workers, by the direction of their heads towards the horizonal pane forming the roof of the hive, and on reaching it, they deposited their burthen nearly in the middle of intervals separating the combs : then they con- veyed the propolis to the real place of its destination. They suspended themselves by the claws of the hind legs to points of support, aftbrded by the viscosity of the propolis on the glass ; and, as it were, swinging themselves backwards and forwards, brought the heap of this substance nearer to the cells at each impulse. Here the bees employed their fore feet, which remained free, to sweep what the teeth had detached, and to unite the fragments scattered over the glass, which recovered all its transparency when the whole propolis was brought to the vicinity of the cells. " After some of the bees had smoothed down and cleaned out the glazed cells, feeling the way with their antennae, one desisted, and having approached a heap of propolis, drew out a thread with its teeth. This being broken off, it was taken in the claws of the fore feet, and the bee, re- entering the cell, immediately placed it in the angle of two portions that had been smoothed, in which operation the fore feet and teeth were used alternately ; but probably proving too clumsy, the thread was reduced and polished; and we admired the accuracy with which it was adjusted when the work was completed. The insect did not stop here : re- turning to the cell, it prepared other parts of it to recive a second thread, for which we did not doubt that the heap would be resorted tOc Contrary to our expectation, however, it availed itself of the portion of the thread cut off on the former occasion, arranged it in the appointed place, and gave it all the solidity and finish of which it was susceptible. Other bees completed the work which the fii'st had begim : and the sides of the cells were speedily seciu'ed with threads of propolis, while some were also put on the orifices ; but we Hive-Bees. 129 could not seize tlie moment wlieu they were varnished, though it may be easily conceived how it is done." * This is not the only use to which bees apply the propolis. They are extremely solicitous to remove such insects or foreign bodies as happen to get admission into tlie hive. When so light as not to exceed their powers, they first kill the insect A^th their stings, and then di'ag it out with their teeth. But it sometimes happens, as was first observed by Maraldi, and since by Eeaumur and others, that an ill-fated slug creci^s into the hive : this is no sooner perceived than it is attacked on all sides, and stung to death. But how are the bees to carry out so heavy a burthen ? Such a labour would be in vain. To prevent the noxious smell which would arise from its putrefaction, they immediately embalm it, by covering every part of its body with propolis, tlu'ough which no eflluvia can escape. When a snail with a shell gets entrance, to dispose of it gives much less trouble and expense to the bees. As soon as it receives the fii'st wound from a sting, it naturally retires within its shell. In this case, the bees, instead of pasting it all over with propolis, content them- selves with gluing all round the margin of the shell, which is sufficient to render the animal for ever inmaovably fixed. Mr. Knight, the learned and ingenious President of the Horticultm'al Society, discovered by accident an artificial substance, more attractive than any of the resins experi- mentally tried by Eeaumur. Having caused the decorti- cated part of a tree to be covered with a cement composed of bees'-wax and turpentine, he observed that this was frec[uented by hive-bees, who, finding it to be a very good propolis ready made, detached it from the tree with their mandibles, and then, as usual, passed it fi'om the first leg to the second, and so on. When one bee had thus collected its load, another often came behind and despoiled it of all it had collected ; a second and a third load were frequently lost in the same manner ; and yet the patient insect pursued its operations without manifesting any signs of anger.f * Huber on Bees, p. 408. t Philosophical Trans, for 1807, p. 242. E 130 Insect Architecture. Probably the latter circumstance, at which Mr. Knight seems to have been surprised, was nothing more than an instance of the division of labour so strikingly exemplified in every part of the economy of bees. It may not be out of place here to describe the apparatus with which the worker-bees are provided for the purpose of carrying the propolis as well as the pollen of flowers to the hive, and which has just been alluded to in the observations of Mr. Knight. The shin or middle portion of the hind pair of legs is actually formed into a triangular basket, admirably adapted to this design. . The bottom of this basket is com- StiUcture of the legs of the Bee, for carrying propolis and pollen, ruagnified. posed of a smooth, shining, horn-like substance, hollowed out in the substance of the limb, and surrounded with a margin of strong and thickly- set bristles. Whatever materials, therefore, may be placed by the bee in the interior of this basket, arc secured from falling out by the bristles around it, whose elasticity will even allow the load to be heaped beyond their points without letting it fall. In the case of propolis, when the bee is loading her singular basket, she fii'st kneads the piece she has detached with her mandibles, till it becomes somewhat dry and less adhesive, as otherwise it would stick to her limbs. This preliminary process sometimes occupies nearly half an hour. Hive-Bees. ] 3 1 Sho then passes it backwards by means of her feet to the cavity of her basket, giving it two or three pats to make it adhere ; and when she adds a second portion to the first, sho often finds it necessary to pat it still harder. When slic has procured as much as the basket will conveniently hold, slic flics ofi:" with it to the hive. The Building of the Cells. The notion coimnonly entertained respecting glass hives is altogether erroneous. Those who are unacquainted with bees, imagine that, by means of a glass hive, all their pro- ceedings may be easily watched and recorded ; but it is to be remembered that bees arc exceedingly averse to the intrusion of light, and their first operation in such cases is to close up every chink by which light can enter to dis- tiu'b them, either by clustering together, or by a plaster composed of propolis. It consequently requires consider- able management and ingenuity, even with the aid of a glass hive, to see them actually at work. M. Huber employed a hive with leaves, which opened in the manner of a book ; and for some purposes he used a glass box, inserted in the body of the hive, but easily brought into view by means of screws. But no invention hitherto contrived is suificicut to obviate every difficulty. The bees are so eager to afibrd mutual assistance, and for this purpose so many of them crowd together in rapid succession, that the operations of indi- viduals can seldom be traced. Though this crowding, how- ever, appears to an observer to bo not a little confused, it is all regulated with admirable order, as has been ascertained by Eeaimiur and other distinguished naturalists. When bees begin to build the hive, they divide tliein- selves into bands, one of which produces materials for the structm-e ; another works upon these, and forms them into a rough sketch of the dimensions and partitions of the cells. All this is completed by the second band, who examine and adjust the angles, remove the superfluous wax, and give the 132 Insect Arcliitedure. work its necessary perfection ; and a third band brings pro- visions to tlie labourers, who cannot leave their work. But no distribution of food is made to those whose charge^ iu collecting propolis and pollen, calls them to the field, because it is supposed they will hardly forget themselves ; neither is any allowance made to those who begin the architecture of the cells. Their province is very trouble- some, because they are obliged to level and extend, as well as cut and adjust the wax to the dimensions required ; but then they soon obtain a dismission from this labour, and retire to the fields to regale themselves with food, and wear off their fatigue with a more agreeable employment. Those who succeed them, draw their mouth, their feet, and the extremity of their body, several times over all the work, and never desist till the whole is polished and completed ; and as they frequently need refreshments, and yet are not permitted to retire, there are waiters always attending, who serve them with provisions when they require them. The labourer who has an appetite, bends down his trunk before the caterer to intimate that he has an inclination to eat, upon which the other opens his bag of honey, and pours out a few drops : these may be distinctly seen rolling through the hole of his trunk, which insensibly swells in every part the liquor flows through. When this little repast is over, the labourer returns to his work, and his body and feet repeat the same motions as before.* Before they can commence building, however, when a colony or swarm migrates from the original hive to a new situation, it is necessary first to collect propolis, with which every chink and cranny in the place where they mean to build may be carefully stopped up ; and secondly, that a quantity of wax be secreted by the wax-workers to form the requisite cells. The secretion of wax, it would aj)pear, goes on best when the bees are in a state of repose ; and the wax-workers, accordingly, suspend themselves in the interior in an extended cluster, like the curtain which is composed of a series of intertwined festoons or garlands, crossing * Spectacle de la Nature, tome i. Ilive-Bees. 133 each other in all directions — the upiicrmost bco maintaining its position by laying hold of the roof with its fore legs, and the succeeding one by laying hold of the hind logs of the first. '' A person," says Reaumur, " must have been born devoid of curiosity not to take interest in the investigation of such wonderful proceedings." Yet Reaumur himself seems not Curtain of Wax-worka's secreting wax. to have understood that the bees suspended themselves in this manner to secrete wax, but merely, as he imagined, to recruit themselves by rest for renewing theii' labours. 134 Insed Architecture. The bees composing the festooned curtain are individually motionless ; but this curtain is, notwithstanding, kept moving by the proceedings in the interior ; for the nurse- bees never form any portion of it, and continue their activity — a distinction with which Eeaumur was unacquainted. Although there are many thousand labom^ers in a hive, they do not commence foimdations for combs in several places at once, but wait till an individital bee has selected a site, and laid the foundation of a comb, which serves as a directing mark for all that are to follow. Were we not expressly told by so accurate an observer as Hubcr, we might hesitate to believe that bees, though united in what api)ears to be an harmonious monarchy, are strangers to subordination, and subject to no discipline. Hence it is, that though many bees work on the same comb, they do not appear to be guided by any simultaneous impulse. The stimulus which moves them is successive. An indi- vidual bee commences each operation, and several others successively apply themselves to accomplish the same pur- pose. Each bee appears, therefore, to act individually, either as directed by the bees preceding it, or by the state of advancement in which it finds the work it has to proceed with. If there be anything like unanimous consent, it is the inaction of several thousand workers while a single individual proceeds to determine and lay down the foun- dation of the first comb. Eeaumur regrets that, though he could by snatches detect a bee at work in founding cells or perfecting their structure, his observations were generally interrupted by the crowding of other bees between him and the little builder. He was therefore compelled rather to infer the different steps of their procedure from an examina- tion of the cells when completed, than from actual observa- tion. The ingenuity of Huber, even under all the disadvan- tages of blindness, succeeded in tracing the minutest operations of the workers from the first waxen j)late of the foundation. We think the narrative of the discoverer's experiments, as given by himself, will be more interesting than any abstract of it which we could furnish : — Hive- Bees. 135 "Having taken a large bcll-sliaped glass receiver, wc glued thin wooden slips to the arch at certain intervals, because the glass itself was too smooth to admit of the bees supporting themselves on it. A swarm, consisting of some thousand workers, several hundred males, and a fertile queen, was introduced, and they soon ascended to the top. Those fii'st gaining the slips fixed themselves there by the fore-feet ; others, scrambling up the sides, joined them, by holding their legs with their own, and they thus formed a kind of chain, fastened by the two ends to the upper parts of the receiver, and served as ladders or a bridge to the workers enlarging their number. The latter were united in a cluster, hanging like an inverted pyramid from the top to the bottom of the hive. " The country then affording little honey, we provided the bees with syrup of sugar, in order to hasten their labour. They crowded to the edge of a vessel containing it ; and, having satisfied themselves, returned to the group. We were now struck with the absolute repose of this hive, contrasted with the usual agitation of bees. Meanwhile, the nurse-bees alone went to forage in the country ; they returned with pollen, kept guard at the entrance of the hive, cleansed it, and stopped up its edges with propolis. The was- workers remained motionless about fifteen hours : the cui'tain of bees, consisting always of the same individuals, assured us that none replaced them. Some hours later, we remarked that almost all these individuals had wax scales under the rings ; and next day this phenomenon was still more general. The bees forming the external layer of the cluster, having now somewhat altered their position, enabled us to see their bellies distinctly. By the projection of the wax scales, the rings seemed edged with white. The cui'tain of bees became rent in several places, and some commotion began to be ' observed in the hive. " Convinced that the combs would originate in the centre of the swarm, our whole attention was then directed towards the roof of the glass. A worker at this time detached itself from one of the central festoons of the cluster, separated itself 136 Insect Architecture. from the crowd, and, with its head, drove away the bees at the beginning of the row in the middle of the arch, turning round to form a space an inch or more in diameter, in which it might move freely. It then fixed itself in the centre of the space thus cleared. " The worker now employing the pincers at the joint of one of the third pair of its limbs, seized a scale of wax pro- jecting from a ring, and brought it forward to its mouth with the claws of its fore-legs, where it appeared in a vertical position. We remarked that, with its claws, it turned the wax in every necessary direction ; that the edge of the scale was immediately broken down, and the fragments having been accumulated in the hollow of the mandibles, issued forth AVax- worker laying the foundation of the first Cell. like a very narrow ribbon, impregnated with a frothy liquid by the tongue. The tongue itself assumed the most varied shapes, and executed the most complicated operations, — being sometimes flattened like a trowel, and at other times pointed like a pencil ; and, after imbuing the whole substance of the ribbon, pushed it forward again into the mandibles, whence it was drawn out a second time, but in an opposite direction. " At length the bee applied these particles of wax to the vault of the hive, where the saliva impregnating them pro- moted their adhesion, and also communicated a whiteness and opacity which were wanting when the scales were detached from the rings. Doubtless this process was to give the wax that ductility and tenacity belonging to its perfect state. The bee then separated those portions not yet applied to use with its mandibles, and with the same organs afterwards arranged them at pleasure. The founder bee, a name appro- priated to this worker, repeated the same operation, until all the fragments, worked up and impregnated with the fluid, ITive-Bees. 137 were attaclicd to the vault, when it repeated the preceding 02)erations on the part of the scale yet kept apart, and again united to the rest what was obtained from it. A second and third scale were similarly treated by the same bee ; yet the work was only sketched ; for the worker did nothing but accumulate the particles of wax together. Meanwhile the founder, quitting its position, disappeared amidst its com- Curtain of Wax-workers (see p. 132). panions. Another, with wax under the rings, succeeded it, which suspending itself to the same spot, withdi-ew a scale by the pincers of the hind legs, and passing it through its mandibles, prosecuted the work ; and taking care to make its deposit in a line with the former, it united their extremities, A third worker, detaching itself from the interior of the cluster, now came and reduced some of the scales to paste, 138 Insect Architecture. and put them near the materials accumulated by its com- panions, but not in a straight line. Another bee, appai'ently sensible of the defect, removed the misplaced wax before our eyes, and carrying it to the former heap, deposited it there, exactly in the order and direction pointed out. " From all these operations was produced a block of a rugged sm-face, hanging down from the arch, without any perceptible angle, or any traces of cells. It was a simple wall, or ridge, running in a straight line, and without the least inflection, two-thirds of an inch in length, above two- thirds of a cell, or two lines, high, and declining towards the extremities. We have seen other foundation walls from an inch to an inch and a half long, the form being always the same ; but none ever of greater height. " The vacuity in the centre of the cluster had permitted us to discover the fii'st manoeuvres of the bees, and the art with which they laid the foundations of their edifices. How- ever, it was filled up too soon for our satisfaction ; for workers collecting on both faces of the wall obstructed our view of their further operations."* * Huber on Bees, p. 358. 139 CHAPTEB VI. AUCHITEOTURE OF THE HIVE-BEE CONTINUED — FOEM OF THE CELLS. T^HE obstruction of whicli M. Huber complains only ope- -*- rated as a stimulus to bis ingenuity in contriving bow be migbt continue bis interesting observations. From tbe time of Pappus to tbe present day, matbcmaticians bave applied tbe principles of geometry to explain tbe construction of tbe cells of a bee-bive; but tbougb tbeir extraordinary regu- larity, and wonderfully-selected form, bad so often been investigated by men of tbe greatest talent, and skilled in all tbe refinements of science, tbe process by wbicb tbey are con- structed, involving also tbe causes of tbeir regularity of form, bad not been traced till M. Huber devoted bimself to tbe inquiry. As tbe wax-workers secrete only a limited quantity of wax, it is indispensably requisite tbat as little as possible of it should be consumed, and tbat none of it sbould be wasted. Bees, tberefore, as M. Eeaumur well remarks,* bave to solve tbis difficult geometrical problem : — a quantity of wax being given, to form of it similar and equal cells of a determinate capacity, but of tbe largest size in proportion to tbe quantity of ma-tter employed, and disposed in such a manner as to occupy tbe least possible space in tbe bive. Tbis problem is solved by bees in all its conditions. Tbe cylindrical form would seem to be best adapted to tbe sbape of tbe insect ; but bad tbe cells been cylindi-ical, tbey could not bave been applied to eacb otber witbout leaving a vacant and superjSuous space between every tlu-ee contiguous cells. Had tbe cells, on tbe otber band, been square or triangular, tbey migbt * Reaumur, vol. v., p. 380. 140 Insect Architecture. have been constructed without unnecessary vacancies ; but these forms would have both required more material, and have been very unsuitable to the shape of a bee's body. The six- sided form of the cells obviates every objection ; and while it fulfils the conditions of the jjroblem, it is equally adapted with a cylinder to the shape of the bee. M. Eeaumur further remarks, that the base of each cell, instead of forming a plane, is usually composed of three pieces in the shape of the diamonds on playing cards, and placed in such a manner as to form a hollow j)yi'amid. This structure, it may be observed, imparts a greater degree of strength, and, still keeping the solution of the problem in view, gives a great caj)acity with the smallest exjjenditure of material. This has actually, indeed, been ascertained by mathematical measurement and calculation. Maraldi, the inventor of glass hives, determined, by minutely measuring these angles, that the greater were 109*^ 28', and the smaller 70° 32' ; and M. Eeaumur, being desirous to know why these particular angles are selected, requested M. Kcenig, a skilful mathematician (without informing him of his design, or tell- ing him of Maraldi's researches), to determine by calculation what ought to be the angle of a six-sided cell, with a concave pyramidal base, formed of three similar and equal rhomboid plates, so that the least possible matter should enter into its construction. By employing what geometricians denominate the infinitesimal calculus, M. Kcenig found that the angles should be 109^ 26' for the greater, and 70° 34' for the smaller, or about two-sixtieths of a degree, more or less, than the actual angles made choice of by bees. The equality of inclination in the angles has also been said to facilitate the construction of the cells. M. Huber adds to these remarks, that the cells of the first row, by which the whole comb is attached to the roof of a hive, are not like the rest ; for, instead of six sides, they have only five, of which the roof forms one. The base, also, is in these different, consisting of three pieces on the face of the comb, and on the other side of two : one of these only is diamond-shaped, while the other two are of an irregular four- Hive-Bees. 141 sided figure. This {irrangemcut, by bringing tbe greatest number of points in contact with the interior surface, insures the stability of tbe comb. It may, however, bo said not to bo quite certain, that Ecaumur and others have not ascribed to bees the merit cf ingenious mathematical contrivance and selection, when the construction of the cells may more probably originate in the form of their mandibles and the other instruments employed in their operations. In the case of other insects, wo have, both in the preceding and subsequent pages of this volume, repeatedly noticed, that they use their bodies, or parts there- of, as the standards of measurement and mcdelling ; and it Arrangemc-nt cf Cells. is not impossible that bees may proceed on a similar principle, M. Huber replies to this objection, that bees are not pro- vided with instruments corresponding to the angles of their cells ; for there is no more resemblance between these and the form of their mandibles, than between the chisel of the sculptor and the work which he produces. The head, ho thinks, does not fui-nish any better explanation. He admits that the antemife are very flexible, so as to enable the insects to follow the outline of every object ; but conchides that neither their structure, nor that of the limbs and mandibles, are adequate to explain the form of the cells, though all these are employed in the operations of building,— the effect, according to him, depending entirely on the object which the insect proposes. We shall now follow M. Huber in the experiments which 142 Insect Architecture. lie contrived, in order to observe the operations of the bees subsequent to their laying a foundation for the fii'st cell ; and we shall again quote from his own narrative : — " It ai^pcarcd to me," he says, " that the only method of isolating the architects, and bringing them individually into view, would be to induce them to cliange the direction of their operations and work upwards. " I had a box made twelve inches square and nine deei?, with a moveable glass lid. Combs, full of brood, honey, and pollen, were next selected from one of my leaf-hives, as con- taining what might interest the bees, and being cut into pieces a foot long, and four inches deep, they were arranged vertically at the bottom of the box, at the same intervals as the insects themselves usually leave between them. A small slip of wooden lath covered the upper edge of each. It was not probable that the bees would attempt to found new combs on the glass roof of the box, because its smoothness pre- cluded the swarm from adhering to it ; therefore, if disposed to build, they could do so over the slips resting on the combs, which left a vacuity five inches high above them. As we had foreseen, the swarm with which this box was peopled established itself among the combs below. We then observed the nurse-bees displaying tlieir natural activity. They dis- persed themselves throughout the hive, to feed the young grubs, to clear out their lodgment, and adapt it for their convenience. Certainly, the combs, which were roughly cr.t to fit the bottom of the box, and in some parts damaged, appeared to them shapeless and misplaced ; for tlicy speedily commenced their reparation. They beat down the old wax, kneaded it between their teeth, and thus formed binding materials to consolidate them. Wo Averc astonished beyond expression by such a multitude of workers employed at once in labours to which it did not appear they should have been called, at their coincidence, their zeal, and their prudence. " But it was still more wonderful, that about half the numerous population took no part in the proceedings, remain- ing motionless, while the others fulfilled the functions required. The wax-workers, in a state of absolute repose, Hive-JSees. 143 recalled our former observations. Gorged with the honey we had put within their reach, and continuing in this condition during twenty-four hours, wax was formed under their rings, and was now ready to he put in operation. To our gi'eat satisfaction, wo soon saw a little foundation-wall rising on one of the slips that we had prepared to receive the superstructure. No obstacle was offered to the progress of our observations ; and for the second time we beheld both the imdertaking of the founder-bee, and the successive labours of several wax-workers, in forming the foundation- wall. AVould that my readers could share the interest which the view of these architects inspired ! " This foimdation, originally very small, was enlarged as the work required ; while they excavated on one side a hollow, of about the -nddth of a coromon cell, and on the opposite surface two others somewhat more elongated. The middle of the single cell corresponded exactly to the partition Foundat:on-wall enlarged, and the Cells commenced. separating the latter : the arches of these excavations, pro- jecting by the accumulation of wax, were converted into ridges in a straight line ; whence the cells of the first row were composed of five sides, considering the slip as one side, and those of the second row, of six sides. " The interior conformation of the cavities, apparently, was derived fi'om the position of their respective outlines. It seemed that the bees, endowed with an admirable delicacy of feeling, directed their teeth j)rincipally to the place where the wax was thickest ; that is, the parts where other workers on the opposite side had accumulated it ; and this exjjlains why the bottom of the cell is excavated in an angular direction behind the projection on the sides of which the sides of the corresponding cells are to rise. The largest of the excava- 144 Insect Architecture. tions, wliicb was opposite to tlu'ee others, was divided into tlii'ee parts, while the excavations of the first row on the other face, applied against this one, were composed of only two. " In consequence of the manner in which the excavations were opposed to each other, those of the second row, and all subsequent, partially applied to three cavities, were composed of three equal diamond-shaped lozenges. I may here remark, that each part of the labour of bees appears the natural result of what has preceded it : therefore, chance has no share in these admirable combinations. " A foundation-wall rose above the slip like a minute vertical partition, five or six lines long, two lines high, but only half a line in thickness ; the edge circular, and the surface rough. Quitting the cluster among the combs, a nurse-bee mounted the slip, turned around the block, and visiting both sides, began to work actively in the middle. It removed as much wax with its teeth as might equal the diameter of a common cell ; and after kneading and moisten- ing the particles, deposited them on the edge of the excava- tion. This insect having laboured some seconds, retired, and was soon replaced by another; a third continued the work, raising the margin of the edges, now projecting from the cavity, and with assistance of its teeth and feet fixing the particles, so as to give these edges a straighter form. More than twenty bees successively participated in the same work ; and when the cavity was little above a line and a half in height, though equalling a cell in mdth, a bee left the swarm, and after encircling the block, commenced its opera- tions on the opposite face, where yet untouched. But its teeth acting only on one half of this side, the hollow which it formed was opposite to only one of the slight prominences bordering the first cavity. Nearly at the same time another worker began on the right of the face that had been un- touched, wherein both were occupied in forming cavities ^vhich may be designed the second and third ; and they also Vv'ere replaced by substitutes. These two latter cavities were separated only by the common margin, framed of particles of Hive-tBees. 145 wax withdrawn from thcan ; which margin corresponded with the centre of the cavity on. the opposite surface. The foundation-wall itself was still of insufficient dimensions to admit the full diameter of a cell : but while the excavations were deei)eiied, wax-workers, extracting their scales of wax, applied them in enlarging its circumference ; so that it rose nearly two lines fui'ther around the circular arch. The nui-se-bees, which appeared more especially cliarged with sculpturing the cells, being then enabled to continue their outlines, prolonged the cavities, and heightened their margins on the new addition of wax. " The arch, formed by the edge of each of these cavities, was next divided as by two equal chords, in the line of which the bees formed stages or projecting borders, or margins meeting at an obtuse angle : the cavities now had four margins, two lateral and perpendicular to the supporting slip, and two oblique, which were shorter. " Meantime, it became more difficult to follow the opera- tions of the bees, from their freqiiently interposing their heads between the eye of the observer and the bottom of the cell ; but the partition, whereon iheir teeth labom-ed, had become so transparent as to expose what passed on the other side. " The cavities of which we speak formed the bottom of the first three cells; and while the bees engaged were advancing them to perfection, other workers commenced sketching a second row of cells above the first, and j)artly behind those in front — for, in general, theii" labour proceeds by combination. We cannot say, ' When bees have finished this cell, they will begin new ones ;' but, ' while particular workers advance a certain portion, we are certain that others ^^■ill carry on the adjacent cells.' Further, the work begun on one face of the comb is already the commencement of that which is to follow on the reverse. All this depends on a reciprocal relation, or a mutual connexion of the parts, rendering the whole subservient to each other. It is un- doubted, therefore, that slight irregularities on the front will affect the form of the cells on the back of the comb." * * Huber on Bees, p. ."GS. L 146 Insect Architecture. When they have in this manner worked the bottoms of the fii'st row of cells into the required forms, some of the nurse- bees finish them by imisarting a sort of polish, while others proceed to cut out the rudiments of a second row from a fresh wall of wax which has been built in the meanwhile by the wax-workers, and also on the opposite side of this wall ; for a comb of cells is always double, being arranged in two layers, placed end to end. The cells of this second row are engrafted on the borders of cavities hollowed out in the wall, being founded by the nurse-bees, bringing the contoui' of all the bottoms, which is at first unequal, to the same level ; and this level is kept uniform in the margins of the cells till they are completed. At first sight nothing appears more simjjle than adding wax to the margins ; but from the inequalities occasioned by the shape of the bottom, the bees must accumu- late wax on the depressions, in order to bring them to a level. It follows accordingly that the sui'face of a new comb is not quite flat, there being a progressive slope produced as the work proceeds, and the comb being therefore in the form of a lens, the thickness decreasing towards the edge, and the last- formed cells being shallower or shorter than those preceding them. So long as there is room for the enlargement of the comb, this thinning of its edge may be remarked ; but as soon as the space within the hive prevents its enlargement, the cells are made equal, and two flat and level surfaces are produced. M. Huber observed, that while sketching the bottom of a cell, before there was any upright margin on the reverse, their pressure on the still soft and flexible wax gave rise to a projection, which sometimes caused a breach of the parti- tion. This, however, was soon repaired, but a slight promi- nence always remained on the opposite surface, to the right and left of which they placed themselves to begin a nevy- excavation ; and they heaped up part of the materials between the two flutings formed by their labour. The ridge thus formed becomes a guide to the direction which the bees are to follow for their vertical furrow of the front cell. We have abeady seen that the fii"st cell determines the Hive-Bees. 147 place of all that succeed it, and two of these arc never, in ordinary circumstances, begun in different parts of the hive at the same time, as is alleged by some early writers. When some rows of cells, however, have been completed in the first comb, two other foundation- walls are begun, one on each side of it, at the exact distance of one-third of an inch, which is sufficient to allow two bees employed on the opposite cells to pass each other without jostling. These new walls are also parallel to the former ; and two more are afterwards begun exterior to the second, and at the same parallel distance. The combs are uniformly enlarged, and lengthened in a progression proportioned to the priority of their origin ; the middle comb being always advanced beyond the two adjoining ones by several rows of cells, and these again beyond the ones exterior to them. Did the bees lay the foundations of all their combs at the same time, they would not find it easy to preserve parallelism and an equality in their distances. It may be remarked further, that beside the vacancies of half an inch between the cells, which form what we call the highways of the community, the combs ai"e pierced in several places with holes which serve as postern-gates for easy communica- tion from one to another, to prevent loss of time in going round. The equal distance between the combs is of more importance to the welfare of the hive than might at fiist appear ; for were they too distant, the bees would be so scattered and dispersed, that they could not reciprocally communicate the heat indispensable for hatching the eggs and rearing the young. If the combs, on the other hand, were closer, the bees could not traverse the intervals wdth the freedom necessary to facilitate the work of the hive. On the approach of winter, they sometimes elongate the cells which contain honey, and thus contract the intervals between the combs. But this expedient is in preparation for a season when it is important to have copious magazines, and when, their activity being relaxed, it is unnecessary for theu- communications to be so spacious and free. On the retiu'n of spring, the bees hasten to contract the elongated cells, that they may become fit for receiving the eggs which 148 Insect Arclvitecture. the queen is about to deposit, and in this manner they re- establish the regular distance.* We are indebted to the late Dr. Barclay of Edinburgh, well known as an excellent anatomist, for the discovery that each cell in a honeycomb is not simply composed of one wall, but consists of two. We shall give the accoimt of his discovery in his own words : — " Having inquired of several naturalists whether or not they knew any author who had mentioned tlaat the partitions between the cells of the honeycomb were double, and whether or not they had ever remarked such a structure themselves, and they having answered in the negative, I now take the liberty of presenting to the Society pieces of honeycomb, in which the young bees had been reared, upon breaking which, it will be clearly seen that the partitions between different cells, at the sides and the base, are all double; or, in other words, that each cell is a distinct, separate, and in some measure an independent structure, agglutinated only to the neighbouring c^Us; and that when the agglutinating sub- stance is destroyed, each cell may be entirely separated from the rest. " I have also some specimens of the cells formed by wasps, which show that the partitions between them arc also double, and that the agglutinating substance between them is more easily destroyed than that between the cells of the bee."f Ikeegulaeities in theie Woekmanship. Though bees, however, work with great uniformity when circumstances favour their operations, they may be com- pelled to vary their proceedings. M. Huber made several ingenious experiments of this kind. The following, men- tioned by Dr. Bevan, was accidental, and occurred to his friend Mr. Walond. " Inspecting his bee-boxes at the end of October, 1817, he perceived that a centre comb, burthened with honey, had separated from its attachments, and was * Huber ou Bees, p. 220. t Memoiis of the Wenieiian Nat. Hist. Soc., vol. ii. p. 26U. Hive-Bees. 149 leaning against another comb so as to prevent the passage of the bees between them. This accident excited great activity in the colony ; but its nature could not be ascer- tained at the time. At the end of a week, the weather being cold, and the bees clustered together Mr. Walond observed, through the window of the box, that they had constructed two horizontal pillars betwixt the combs alluded to, and had removed so much of the honey and wax from the top of each as to allow the passage of a bee : in about ten days more there was an uninterrupted thorouglifare ; the detached comb at its upper part had been secured by a strong barrier, and fastened to the window with the spare wax. This being accomplished, the bees removed the hori- zontal pillars lirst constructed, as being of no further use."* A similar anecdote is told by M. Huber. " During the winter," says he, "a comb in one of my bell-glass hives, liaving been originally insecure, fell down, but preserved its position parallel to the rest. The bees were unable to fill up the vacuity left above it, because they do not build combs of old wax, and none new could be then obtained. At a more favourable season they would have engrafted a new comb on the old one ; but now their provision of honey could not be spared for the elaboration of this substance, which induced them to iusm-e the stability of the comb by another process. " Crowds of bees taking wax from the lower part of other combs, and even gnawing it from the siu'face of the orifices of the deepest cells, they constructed so many ii'reguiar pillars, joists, or buttresses, between the sides of the fallen comb, and others on the glass of the hive. All these were artificially adapted to localities. Neither did they confine themselves to repairing the accidents which their works had sustained. They seemed to profit by the warning to guard against a similar casualty. •' The remaining combs were not displaced ; therefore, while solidly adhering by the base, we were greatly surprised to see the bees strengthen their principal fixtures with old * Bevnii on Bees, p. 326. 150 Insect Architecture. wax. They rendered them much tliicker than before, and fabricated a number of new connections, to unite them more firmly to each other and to the sides of their dwelling. All this passed in the middle of January, a time that these insects commonly keep in the upper part of their hive, and when work is no longer seasonable,"* M. Huber the younger shrewdly remarks, that the ten- dency to symmetry observable in the architectiu-e of bees does not hold so much in small details as in the whole work, because they are sometimes obliged to adapt themselves to particular localities. One irregularity leads on to another, and it commonly arises from mere accident, or from design on the part of the proprietor of the bees. By allowing, for instance, too little interval betv/een the spars for receiving the foundation of the combs, the structure has been continued in a particular direction. The bees did not at first appear to be sensible of the defect, though they afterwards began to suspect their error, and were then observed to change their line of work till they gained the customary distance. The cells having been by this change of direction in some degree curved, the new ones which were commenced on each side of it, by being built everywhere parallel to it, partook of the same curvature. But the bees did not relish such approaches to the " line of beauty," and exerted themselves to bring their buildings again into the regular form. In consequence of several irregiilarities which they wished to correct, the younger Huber has seen bees depart from their usual practice, and at once lay on a spar tv/o foundation- walls not in the same line. They could consequently neither be enlarged without obstructing both, nor from their position could the edges unite, had they been prolonged. The little architects, however, had recourse to a very ingenious con- trivance : they curved the edges of the two combs, and brought them to unite so neatly that they could be both prolonged in the same line with ease ; and when carried to some little distance, their surface became quite uniform and level. * Huber on Bees, p. 416. Hive-Bees. 151 " Having seen bees," says the elder Huber, " work both up and down, I wished to try to investigate whether we could compel them to construct their combs in any other direction. We endeavoured to puzzle them with a hive glazed above and below, so that they had no place of support but the upright sides of their dwelling ; but, betaking themselves to the upper angle, they built combs perpendicular to one of these sides, and as regularly as those which they usually build imder a horizontal surface. The foimdations were laid on a place which does not serve naturally for the base, yet, except in the difference of direction, the first row of cells resembled those in ordinary hives, the others being dis- tributed on both faces, while the bottoms alternately corre- sponded with the same symmetry. I put the bees to a still greater trial. As they now testified their inclination to carry theii' combs, by the shortest way, to the opposite side of the hive (for they prefer uniting them to wood, or a sm'face rougher than glass), I covered it with a pane. Whenever this smooth and slippery substance was interposed between them and the wood, they departed from the straight line hitherto followed, and bent the structui-e of their comb at a right angle to what was already made, so that the pro- longation of the extremity might reach another side of the hive, which had been left free. " Varying this experiment in several ways, I saw the bees constantly change the direction of their combs, when I presented to them a surface too smooth to admit of theii- clustering on it. They always sought the wooden sides. I thus compelled them to cm-ve the combs in the strangest shapes, by placing a pane at a certain distance fi-om their edges. These results indicate a degree of instinct truly wonderfid. They denote even more than instinct : for glass is not a substance against which bees can be warned by nature. In trees, their natural abode, there is nothing that resembles it, or with the same polish. The most singular part of their proceeding is changing the direction of the work before arriving at the sui'face of the glass, and while yet at a distance suitable for doing so. Do they anticipate 152 Insect Architecture the inconvenience wMcli would attend any other mode of building ? No less curious is the plan adopted by the bee for producing an angle in the combs : the wonted fashion of their work, and the dimensions of the cells, must be altered. Therefore, the cells on the upper or convex side of the combs are enlarged ; they are constructed of three or four times the width of those on the opposite surface. How can so many insects, occupied at once on the edges of the combs, concur in giving them a common curvature from one extremity to the other ? How do they resolve on establishing cells so small on one side, while dimensions so enlarged are bestowed on those of the other ? And is it not still more singular, that they have the art of making a correspondence between cells of such reciprocal discrepance ? The bottom being common to both, the tubes alone assume a taper form. Perhaps no other insect has afforded a more decisive proof of the resources of instinct, when compelled to deviate from the ordinary course. "But let us study them in their natural state, and there we shall find that the diameter of their cells must be adapted to the individuals which shall be bred in them. The cells of males have the same figm-e, tlie same number of lozenges and sides, as those of workers, and angles of the same size. Their diameter is S{- lines, while those of workers are only 2|-. ■'It is rarely that the cells of males occupy the higher part of the combs. They are generally in the middle or on the sides, where they are not isolated. The manner in which they are surrounded by other cells alone can explain how the transition in size is effected. When the cells of males are to be fabricated under those of workers, the bees make several rows of intermediate cells, whose diameter augments progressively, until gaining that proportion proper to the cells required ; and in returning to those of workers, a lowering is observed in a manner corresponding. " Bees, in preparing the cells of males, jjreviously esta- blish a block or lump of wax on the edge of their comb, thicker than is usually employed for those of workers. It is Hive-Bees. 153 also made liighcr, otherwise tlie same order and symmetry could not be preserved on a larger scale. " Several naturalists notice the irregularities in the cells of bees as so many defects. What would have been their astonishment had they observed that part of them are tlie result of calculation ? Had they followed the imperfection of their organs, some other means of compensating them would have been granted to the insects. It is much more surprising that they know how to quit the ordinary route, when circumstances demand the construction of enlarged cells ; and, after building thirty or forty rows of them, to return to the proper proportions from which they have departed by successive reductions. Bees also augment the dimensions of their cells when there is an opportunity for a great collection . of honey. Not only are they then con- structed of a diameter much exceeding that of the common cells, but they are elongated throughout the whole space admitting it. A great portion of irregular comb contains cells an inch, or even an inch and a half, in depth. " Bees, on the contrary, sometimes are induced to shorten their cells. When Avishing to prolong an old comb, whose cells have received their full dimensions, they gradually reduce the thickness of its edges, by gnawing down the sides of the cells, until they restore it to its original lenti- cular form. They add a waxen block around the whole circumference, and on the edge of the comb construct pyra- midal bottoms, such as those fabricated on ordinary occa- sions. It is a certain fact, that a comb never is extended in any direction unless the bees have thinned the edges, which are diminished throughout a sufficient space to remove any angular projection. " The law which obliges these insects partly to demolish the cells on the edges of the comb before enlarging it, un- questionably demands more profound investigation. How can we account for instinct leading them to undo what they have executed with the utmost care ? The wonted regular gradation which may be necessary for new cells, subsists among those adjoining the edges of a comb recently con- 154 Insect Architecture. structed. But afterwards, when those on the edge are deepened like the cells of the rest of the surface, the bees no longer preserve the decreasing gradation which is seen in the new combs." * The Finishing of the Cells. While the cells are building they appear to be of a dull white colour, soft, even, though not smooth, and translucent ; but in a few days they become tinged with yellow, particu- larly on the interior surface ; and their edges, from being thin, uniform, and yielding, become thicker, less regular, more heavy, and so firm that they will bend rather than break. New combs break on the slightest touch. There is also a glutinous substance observable q,round the orifices of the yellow cells, of reddish colour, unctuous, and odori- ferous. Threads of the same substance are applied all around the interior of the cells, and at the summit of their angles, as if it were for the purpose of binding and strengthening the walls. These yellow cells also require a much higher temperature of water to melt them than the white ones. It appeared evident, therefore, that another substance, different from wax, had been employed in varnishing the orifices, and strengthening the interior of the cells. M. Huber, by numerous experiments, ascertained the resinous threads lining the cells, as well as the resinous substance around their orifice, to be propolis ; for he traced them, as we mentioned in our account of propolis, from the poplar buds where they collected it, and saw them apply it to the cells ; but the yellow colour is not imparted by propolis, to which it bears no analogy. We are, indeed, by no means certain what it is, though it was proved by experiment not to arise from the heat of the hives, nor from emanations of honey, nor from particles of pollen. Perhaps it may be ascribed to the. bees rubbing their teeth, feet, and other parts of their body, on the surfaces where they seem to rest ; or to their tongue (haustellum) sweeping from right to left like a fine * Hubei- on Bees, p. 391. Hive-Bees. 155 pliant pencil, AA'lien it appears to leave some sprinkling of a transparent liquid. Besides painting and varnishing tlieir cells in this manner, they take care to strengthen the weaker part of their edifice by means of a mortar composed of propolis and wax, and named pissoceros* by the ancients who fii-st observed it, though Keaumxir was somewhat doubtful respecting the ex- istence of such a composition. We are indebted to the shrewd observations of Huber for a reconcilement of the Eoman and the French naturalists. The details which he has gif en of his discovery are perhaps the most interesting in his delightful book. " Soon," he says, " after some new combs had been finished in a hive, manifest disorder and agitation prevailed among the bees. They seemed to attack theix own works. The primi- tive cells, whose structiu'e we had admired, were scarcely recognizable. Thick and massive walls, heavy, shapeless pillars, were substituted for the slight partitions previously built with such regularity. The substance had changed along with the form, being composed apparently of wax and propolis. From the perseverance of the workers in their devastation, we suspected that they proposed some useful alteration of their edifices ; and our attention was directed to the cells least injured. Several were yet un- touched ; but the bees soon rushed precipitately on them, destroyed the tubes, broke down the wax, and threw all the fragments about. But we remarked that the bottom of the cells of the first row were spared ; neither were the corresponding parts on both faces of the comb demolished at the same time. The bees laboured at them alternately, leaving some of the natural supports, otherwise the comb would have fallen down, which was not their object : they \vished, on the contrary, to provide it a more solid base, and to secure its union to the vault of the hive, with a substance whose adhesive properties infinitely surpassed those of wax. The propolis employed on this occasion had been deposited in a mass over a cleft of the hive, and had hardened in * Fiom two Greek words, signifying pitch and icax. 156 Lised Architecture. drying, which probably rendered it more suitable for the purpose. But the bees experienced some difficulty in making any impression on it ; and we thought, as also had ajjpeared to M. de Eeaumur, that they softened it with the same fi-othy matter from the tongue which they use to render wax more ductile. " We very distinctly observed the bees mixing fragments of old wax with the propolis, kneading the two substances together to incorporate them ; and the compound was em- ployed in rebuilding the cells that had been destroyed. But they did not now follow their ordinary rules of architecture, for they were occupied by the solidity of their edifices alone. Night intervening, suspended our observations, but next morning coniirmed what we had seen. " We find, therefore, that there is an epoch in the labour of bees, when the upper foundation of their combs is con- structed simply of wax, as Reaumur believed ; and that, after all the requisite conditions have been attained, it is converted to a mixture of wax and propolis, as remarked by Pliny so many ages before us. Thus is the apparent contradiction between these two great naturalists explained. But this is not the utmost extent of the foresight of these insects. When they have plenty of wax, they make their combs the full breadth of the hive, and solder them to the glass or wooden sides, by structures more or less approaching the form of cells, as circumstances admit. But should the supply of wax fail before they have been able to give sufficient diameter to the combs whose edges are rounded, large inter- vals remain between them and the upright sides of the hive, and they are fixed only at the top. Therefore, did not the bees provide against it, by constructing great pieces of wax mixed with propolis, in the intervals, they might be borne down by the weight of the honey. These pieces are of irregular shape, strangely hollowed out, and their cavities void of symmetry."* It is remarked by the lively Abbe la Pluche, that the foundations of our houses sink with the earth on which they * Hubei- on Bees, p. 415. Rive-Bees. 157 arc built, the walls begin to stoop by degrees, tlicy nod with age, and bend from their j)erpendicular ; — lodgers damage everything, and time is continually introducing some new decay. The mansions of the bees, on the contrary, grow stronger the oftencr they change inhabitants. Every bee- grub, before its metamorphosis into a nymph, fastens its skin to the partitions of its cell, but in such a manner as to make it correspond with the lines of the angle, and without in the least disturbing the regularity of the figure. During sum- mer, accordingly, the same lodging may serve for three or four grubs in succession ; and in the ensuing season it may accommodate an equal number. Each grub never fails to fortify the panels of its chamber by arraying them with its spoils, and the contiguous cells receive a similar augment- ation from its brethren.* Reaumur found as many as seven or eight of these skins spread over one another : so that all the cells being inci-usted with six or seven coverings, well di'ied and cemented with propolis, the whole fabric daily acquii-es a new degree of solidity. It is obvious, however, that by a repetition of this process the cell might be rendered too contracted ; but in such a case the bees know well how to proceed, by tui*ning the cells to other uses, such as magazines for bee-bread and honey. It has been remarked, however, that in the hive of a new swarm, diu-ing the months of July and August, there are fewer small bees or nurse-bees than in one that has been tenanted four or five years. The workers, indeed, clean out the cell the moment that a young bee leaves its cocoon, but they never detach the sillvy film which it has previously spun on the w^alls of its cell. But though honey is deposited after the yoimg leave the cells, the reverse also happens ; and accordingly, when bees are bred in contracted cells, they are by necessity smaller, and constitute, in fact, the im- portant class of nurse-bees. We are not disposed, however, to go quite so far as an American periodical WT.-iter, who says, " Thus we see that tlic contraction of the cell may diminish the size of a bee, * Spectacle de la Nature, vol. i. 158 Insect Architecture. even to the extinction of life, just as the contraction of a Chinese shoe reduces the foot even to uselessness."* We know, on the contrary, that the queen-bee will not deposit eggs in a cell either too small or too large for the proper rearing of the young. In the case of large cells, M. Huber took ad- vantage of a queen that was busy depositing the eggs of workers to remove all the common cells adapted for their reception, and left only the larger cells appropriated for males. As this was done in June, when bees are most active, he expected that they would have immediately re- paired the breaches he had made ; but to his great surprise they did not. make the slightest movement for that purpose. In the meanwhile the queen, being oppressed by her eggs, was obliged to drop them about at random, preferring this to depositing them in the male cells, which she knew to be too large. At length she did deposit six eggs in the large cells, which were hatched as usual three days after. The nui'se- bees, however, seemed to be aware that they could not be reared there, and thoagh they supplied them with food, did not attend to them regularly. M. Huber found that they had been all removed from the cells during the night, and the business both of laying and nursing was at a complete stand for twelve days, when he supplied them again with a comb of small cells, which the queen almost immediately filled with eggs, and in some cells she laid five or six. [The accompanying illustration exhibits these three kinds of bees, namely, the Queen, the Drone, and the Worker, together with the cells which they resj)ectively inhabit. Fig. 1 shows the queen-bee as she appears when in com- mand of a hive. When she fii'st issues from the royal cell, she is much smaller in the body, and an inexperienced observer might have some dif&culty in distinguishing her from an ordinary worker. But any one who has been ac- customed to bees can pick her out as soon as his eyes rest upon her. Her body is rather larger and narrower than those of the workers, and the wings are shorter in i^roportion, slightly crossing at the tips when she is at rest. Fig. 2 * North Americiui Rev., Oct. 1828. p. 355. Hive-Bees. 159 represents the common worker-bee, wliicli, as has already- been mentioned, is simply an undeveloped female. Fig. 3 is the male or di-one-bcc, which is easily distinguishable, even by a novice. He is larger, stouter, and heavier built than the female ; his eyes are so enormous that they seem to occupy nearly the entire head, and he has some well- defined tufts of hair on the end of the abdomen. He can even be detected by the ear, as he flies, the deep droning hum being quite unlike the fussy, business-like soimd produced by the w^orker. Fig. 4 represents one of the royal cells, a little reduced in size. In making this cell, the bees lose sight of their habitual economy of wax, and use enough material for fifty ordinary cells. It is probable that the great size of the cell enables the inclosed insect to expand, and so to be capable of becoming the mother as well as the ruler of her subjects. The royal cell is always placed at the edge of a comb, so as not to interfere with the other cells, which 160 Insect AreJdteeture. contain lioney, bee-bread, and grubs ; and in each hive there are generally several of these cells in different stages of structure. Figs. 5 and 6 represent the proportionate sizes of the cells which contain the drone and worker bees.] The architecture of the hive, which we have thus detailed, is that of bees receiving the aid of human care, and having external coverings of a convenient form, prepared for their reception. In this country bees are not found in a wild state ; though it is not xmcommon for swarms to stray from theii- proprietors. But these stray swarms do not spread colonies through our woods, as they are said to do in America. In the remoter parts of that continent there are no wild bees. They precede civilization ; and thus when the Indians observe a swarm they say, "The wliite man is coming." There is evidence of bees having abounded in these islands, in the earlier periods of our history ; and Ireland is particularly mentioned by the Venerable Bede as being " rich in milk and honey." * The hive-bee has formed an object of economical culture in Eiirope at least for two thousand years ; and Varro describes the sort of hives used in his time, 1870 years ago. We are not aware, however, that it is now to be found wild in the milder clime of Southern Europe, any more than it is in om- own island. The wild bees of Palestine principally hived in rocks. " He made him," says Moses, " to suck honey out of the rock."f " With honey out of the rock," says the Psalmist, "should I have satisfied thee." J In the caves of Salsette and Elephanta, at the present day, they hive in the clefts of the rocks, and the recesses among the fissm'cs, in such numbers as to become very troublesome to visitors. Their nests hang in innumerable clusters. § We are told of a little black stingless bee found in the island of Guadaloupe, which hives in hollow trees or in the cavities of rocks by the sea-side, and lays " up honey * "Hibernia dives lactis ac mellis insula." — Beda, Hist. Eccles. i. 7. t Deut. xxxii. 13. J Psalm Ixxxi. 16. § Forbes, Orien. Mem. i. Hive-Bees. 161 in cells about the size and shape of pigeons' eggs. These cells are of a black or deep-violet colour, and so joined together as to leave no sjmce between them. They hang in clusters almost like a bunch of gi-apes."* The following arc mentioned by Lindley as indigenous to Brazil. " On an excursion towards Upper Tapagippe," says he, " and skirting the dreary woods which extend to the interior, I observed the trees more loaded with bees' nests than even in the neighbourhood of Porto Seguro. They consist of a pon- derous shell of clay, cemented similarly to martins' nests, swelling from high trees about a foot thick, and forming an oval mass full two feet in diameter. When broken, the wax is arranged as in oiu' hives, and the honey abundant." f Captain Basil Hall found in South America the hive of a honey-bee very different from the Brazilian, but nearly allied to, if not the same as, that of Guadaloupe. " The hive we saw opened," he says, " was only partly filled, which enabled us to see the economy ol the interior to more advantage. The honey is not contained in the elegant hexagonal cells of om* hives, but in wax bags, not quite so large as an egg. These bags or bladders are hung round the sides of the hive, and aj)pear about half full ; the quantity being probably just as gi-eat as the strength of the wax will bear without tearing. Those near the bottom, being better supported, are more filled than the upper ones. In the centre of the lower part of the hive we observed an irregularly-shaped mass of comb, furnished with cells like those of our bees, all containing young ones in such an ad- vanced state, that, when we broke the comb, and let them out, they flew merrily away." Clavigero, in his 'History of Mexico,' evidently describing the same species of bee, says it abounds in Yucatan, and makes the honey of Estabentum, the finest in the world, and which is taken every two months. He mentioned another species of bee, smaller in size, and also without a sting, which foi-ms its nest of the shape of a sugar-loaf, and as large * Amer. Q. Rev., iii. p. 383. ■f Roy. Jlil. Chron. quoted by Kirby and Spence, M 162 Insect Architecture. or larger. These are suspended from trees, particularly from the oak, and are much more populous than our common hives. Wild honey-bees of some species appear also to abound in Africa. Mr. Park, in his second volume of travels, tells us that some of his associates imprudently attempted to rob a numerous hive of its honey, when the exasperated bees, rushing out to defend their property, attacked their assail- ants with great fury, and quickly compelled the whole com- pany to fly. At the Cape of Good Hope the bees themselves must be less formidable, or more easily managed, as their hives are sought for with avidity. Nature has tliere provided man with a singular and very ef&cient assistant in a bird, most ap- propriately named the honey-guide {Indicator major, Veillot ; Cuculus indicator, Latham). The honey-guide, it is said, so far from being alarmed at the presence of man, appears anxioiis to court his acquaintance, and flits from tree to tree with an expressive note of invitation, the meaning of which is both well known to the colonists and the Hottentots. A person thus invited by the honey-guide seldom refuses to follow it onward tiU it stops, as it is certain to do, at some hollow tree containing a bee-hive, usually well stored with honey and wax. It may be that the bird finds itself in- adequate to the attack of a legion of bees, or to penetrate into the interior of the hive, and is thence led to invite an agent more powerful than itself. The person invited, indeed, always leaves the bird a share of the spoil, as it would be considered sacrilege to rob it of its due, or in any way to injure so sacred a bird. Useful, however, as is the honey-guide, it must always be carefully watched, and the traveller must not follow it with- out keeping his eyes well open. For although, as a general fact, the bii'd will lead its followers to honey, it has a strange habit of leading them to the spot where lies hidden some dangerous animal. Sometimes it brings them to a rhinoceros, wallowing in a mud pool. Sometimes it directs them to a solitary buffalo, one of the most dangerous animals that Hive-Bees. 1G3 Southern Africa produces, and one v.liicli the natives fear but little less than the lion itself. And more than once the too-confiding traveller has followed the honey-guide, and been led to a spot where was lying one of the venomous serpents. The Americans, who have not the African honey-guide, employ several well-knoA\Ti methods to track bees to their hives. One of the most common though ingenious modes is to place a piece of bcc-bread on a flat surface, a tile for instance, surrounding it with a circle of wet white paint. The bee, whose habit it is always to alight on the edge of any plane, has to travel through the paint to reach the bee- bread. When, therefore, she flies off, the observer can track her by the white on her body. The same operation is repeated at another place, at some distance from the first, and at right angles to the bee-line just ascertained. The position of the hive is easily determined, for it lies in the angle made by the intersection of the bee-lines. Another method is described in the ' Philosophical Transactions for 1721.' The bee-hunter decoys, by a bait of honey, some of the bees into his trap, and when he has seciu'ed as many as he judges will suit his purpose, he encloses one in a tube, and, letting it fly, marks its course by a pocket-compass. Departing to some distance, he liberates another, observes its course, and in this manner determines the position of the hive, upon the principle already detailed. These methods of bee-hunting depend upon the insect's habit of always flying in a right line to its home. Those who have read Cooper's tale of the ' Prairie ' must well remember the character of the bee-hunter, and the expression of " lining a bee to its hive." In reading these and similar accounts of the bees of distant parts of the world, we must not conclude that the descriptions refer to the same species as the common honey- bee. There are numerous species of social bees, which, while they differ in many circumstances, agree in the practice of storing up honey, in the same way as we have numerous species of the mason-bee and of the humble-bee. 164 CHAPTEB VII. CAKPENTEY 05" TREE-HOPPERS AND SAW-FLIES. ^"^HE operations of an insect in boring into a leaf or a bud to -*- form a lodgment for its eggs aj^pear very simple. The tools, however, by wliich these effects are performed are very complicated and curious. In the case of gall-flies (Cynics), the operation itself is not so remarkable as its subsequent chemical effects. These effects are so different from any others that may be classed under the head of Insect Architec- ture, that we shall reserve them for the latter part of this volume, although, with reference to the use of galls, the protection of eggs and larvae, they ought to find a place here. We shall, however, at present confine ourselves to those which simply excavate a nest, without producing a tumour. The first of these insects which we shall mention is celebrated for its song, by the ancient Greek poets, under the name of Tetiix. The Eomans called it Cicada^ which we sometimes, but erroneously, translate " grasshopper ;" for the grasshoppers belong to an entirely different order of insects. We shall, therefore, take the liberty of calling the Cicadas Tree-hoppers, to which the cuckoo-spit insect (Tetti- ffonia spumaria, Oliv.) is allied ; but there is only one of the true Cicadte hitherto ascertained to be British, namely, the Cicada hcBmatodes (Linn.), which was discovered in the New Forest, Hampshire, by Mr. Daniel Bydder. M. Eeaumur was exceedingly anxious to study the economy of these insects ; but they not being indigenous in the neigh- bourhood of Paris, he commissioned his friends to send him some from more southern latitudes, and he procured in this way specimens not only from the South of France and from Italy, but also from Egypt. From these specimens he has given the best account of them yet published ; for though, Tree-Hoppers. 165 as he tells us, lie had never had the i)lcasiire of seeing one of them alive, the most interesting i)arts of their structure can be studied as well in dead as in living specimens. We oiu-- selves possess several specimens from New Holland, upon which we have verified some of the more interesting observa- tions of Reaumiu'. Vii-gil tells us that in his time "the cicadje burst the very shrubs with their querulous music ;"* but we may well suppose that he was altogether unacc[uainted ^rtith the singular instrument by means of which they can, not poetically, but actually, cut grooves in the branches they select for deposit- ing their eggs. It is the male, as in the case of birds, which fills the woods with his song ; while the female, though mute, is no less interesting to the natui-alist on account of her cui'ious ovipositor. This instrument, like all those with which insects are fui-nished by natiu'e for cutting, notching, or piercing, is composed of a horny substance, and is also considerably larger than the size of the tree-hopper would proportionally indicate. It can on this account be partially examined without a microscope, being, in some of the larger species, no less than five linesf in length. The ovipositor, or auger (tariere), as Reaumur calls it, is lodged in a sheath which lies in a groove of the terminating ring of the belly. It requii-es only a very slight pressure to cause the instrument to protrude from its sheath, when it appears to the naked eye to be of equal thickness thi-oughout, except at the point, where it is somewhat enlarged and angular, and on both sides finely indented with teeth. A more minute examination of the sheath demonstrates that it is composed of two horny pieces slightly curved, and ending in the form of an elongated spoon, the concave part of which is adapted to receive the convex end of the ovipositor. When the protruded instrument is further examined with a microscope, the denticulations, nine in number oil each side, appear strong, and arranged with great symmetry, increasing in fineness towards the point, where there are three or four * " Cantu querulae rumpent arbusta cicadse." — Geoig. iii. 328 t A line is about the twelfth part of an inch. 166 Insect Architecture. very small ones, beside the nine that are more obvious. The magnifier also shows that the instrument itself, which appeared simple to the naked eye, is, in fact, composed of three differ- ent pieces ; two exterior armed with the teeth before men- tioned, denominated by Reaumur files (limes), and another pointed like a lancet, and not denticulated. The denticulated pieces, moreover, are capable of being moved forwards and backwards, while the centre one remains stationary ; and as this motion is effected by pressing a pin or the blade of a knife over the muscles on either side at the origin of the OAdpositor, it may be presumed that those muscles are destined for producing similar movements when the insect requires them. By means of a finely-pointed pin carefully introduced between the pieces, and pushed very gently downwards, they may be, with no great difficulty, separated in their whole extent. The contrivance by which those three pieces are held united, while at the same time the two files can be easily put in motion, is similar to those of our own mechanical inven- tions, with this difference, that no human workman could construct an instrument of this description so small, fine, exquisitely polished, and fitting so exactly. We should have been apt to form the gi'ooves in the central piece, whereas they are scooped out in the handles of the files, and play upon two projecting ridges in the central piece, by which means this is rendered stronger. M. Eeaumur discovered that the best manner of showing the play of this extraor- dinary instrument is to cut it off with a pair of scissors near its origin, and then, taking it between the thumb and the finger at the point of section, work it gently to put the files in motion. Beside the muscles necessary for the movement of the files, the handle of each is terminated by a curve of the same hard horny substance as itself, which not only furnishes the muscles with a sort of lever, but serves to press, as with a spring, the two files close to the central piece, as is shown in the lower figure. M. Pontedera, who studied the economy of the tree-hoppers Tree-HojJj^ers. 167 n'ith some care, was anxious to see the insect itself make uso of the ovipositor in forming grooves in wood, but found that it was so shy and easily alarmed, that it took to flight when- ever ho approached ; a circimistance of which Eeaumur takes Ovipositors, with files, of Tree-hopper, magniSed. advantage, to soothe his regret that the insects were not indigenous in his neighbourhood. But of their workmanship, when completed, he had several specimens sent to him from Provence and Languedoc by the Marquis de Caumont. The gall-flies, when about to deposit their eggs, select growing i^lants and trees ; but the tree-hopj)ers, on the con- trary, make choice of dead, dried branches, for the mother Excavations for eggs of Tree-hopper, with the chip-lids raised. seems to be aware that moisture would injure her progeny. The branch, commonly a small one, in which eggs have been deposited, may be recognised by being covered with little 168 Insect Architecture. oblong elevations caused by small splinters of tbe wood, detached at one end, but left fixed at the other, by the insect. These elevations are for the most part in a line, rarely in a double line, nearly at equal distances from each other, and form a lid to a cavity in the wood about four lines in length, containing from four to ten eggs. It is to be remarked that the insect always selects a branch of such dimensions that it can get at the pith, not because the pith is more easily bored, for it does not penetrate into it all, but to form a warm and safe bed for the eggs. M. Pontedera says, that when the eggs have been deposited, the insect closes the mouth of the hole with a gum cajjablc of protecting them from the weather ; but M. Eeaumur thinks this only a fancy, as, out of a great number which he examined, he could discover nothing of the kind. Neither is such a protection wanted ; for the woody splinters above mentioned furnish a very good covering. The grubs hatch from these eggs (of which, M. Pontedera says, one female will deposit from five to seven hundred), issue from the same holes through which the eggs have been introduced, and betake themselves to the ground to feed on the roots of plants. They are not transformed into chrysa- lides, but into active nymphs, remarkable for their fore limbs, which are thick, strong, and fm-nished with j^rongs for dig- ging ; and when we are told, by Dr. Le Ferve, that they make their way easily into hard stiff clay, to the depth of two or three feet, we perceive how necessary to them such a con- formation must be. Saw-flies. An instrument for cutting grooves in wood, still more ingeniously contrived than that of the tree-hopper, was first observed by Vallisnieri, an eminent Italian naturalist, in a four-winged fly, most appropriately denominated by M. Eeau- mur the saw-fly (Tenihredo), of which many sorts are in- digenous to Great Britain. The grubs from which these flies originate are indeed but too well known, as they frequently strip our rose, gooseberry, raspberry, and red currant trees of their leaves, and are no less destructive to birch, alder, and Tree-Koppers. 1G9 willows ; while tiu-nips aucl wheat suffer still more serioiisly by their ravages. These grubs may readily be distinguished from the caterpillars of moths aud butterflies by having from sixteen to twenty-eight feet, by which they usually hang to the leaf they feed on, while they coil up the hinder i)art of their body iu a spiral ring. The perfect flies are distin- guished by four transparent wings ; and some of the most common have a flat body of a yellov/ or orange colour, while the head and shoulders are black. In order to see the ovipositor, to which wo shall for the present turn oiu- chief attention, a female saw-fly musb be taken, and her belly gently pressed, when a narrow slit will be observed to open at some distance from the apex, aud a short, pointed, and somewhat curved body, of a bro^vn colour a. Ovipositor of Saw-fly, protruded from its sLeatb, rcagnifled. and horny substance, will be protruded. The curved plates which form the sides of the slit are the termination of the sheath, in which the instrument lies concealed till it is wanted by the insect. The appearance of this instrument, however, and its sing-ular structure, cannot 'be well under- stood without the aid of a microscoiDe. The instrument thus brought into view is a very finely- contrived saw, made of a horny substance, and adapted for penetrating branches and other parts of plants where the eggs are to be deposited. The ovipositor- saw of the insect is much more complicated than any of those employed by our carpenters. The teeth of oui- saws are formed in a line, but in such a manner as to cut in two lines parallel to, and at a 170 Insect Architecture. small distance ■from, each other. This is effected, by slightly bending the points of the alternate teeth right and left, so that one-half of the whole teeth stand a little to the right, and the other half a little to the left. The distance of the two parallel lines thus formed is called the course of the saw, and it is only the portion of wood which lies in the course that is cut into saw-dust by the action of the instrument. It will follow that in proportion to the thinness of a saw there will be the less destruction of wood which may be sawed. When cabinet-makers h.ive to divide valuable wood into very Ovipositor-saw of Saw-fly, with rasps shown In the cross lines. thin leaves, they accordingly employ saws with a narrow course, while sawyers who cut planks use one with a broad course. The ovipositor-saw being extremely fine, does not require the teeth to diverge much ; but from th^ manner in which they operate, it is requisite that they should not stand, like those of our saws, in a straight line. The greater portion of the edge of the instrument, on the contrary, is towards the point somewhat concave, similar to a scythe, while towards the base it becomes a little convex, the whole edge being nearly the shape ot an Italic /. The ovipositor-saw of the fly is put in motion in the same way as a carpenter's hand-saw, supposing the tendons attached Saw-Flies. Ill to its base to form tlic handle, and tlie muscles wliicli put it in motion to Lc the hand of tho carpenter. But the carpcntei" can only work one saw at a time, whereas each of these flies is furnished with two, equal and similar, which it works at the same time — one being advanced and the other retracted alternately. The secret, indeed, of working more saws than one at once is not unknown to our mechanics ; for two or three are sometimes fixed in the same frame. These, how- ever, not only all move upwards and downwards simulta- neously, biit cut the wood in different places ; while the two saws of the ovipositor work in the same cut, and consequently, though the teeth arc extremely fine, the effect is similar to a saw with a wdde set. It is important, seeing that the ovipositor- saws are so fine, that they be not bent or separated while in operation — and this, also, nature has provided for, by lodging the backs of the saws in a groove, formed by two membranous plates, similar to the structure of a clasp-knife. These plates are thickest at the base, becoming gradually thinner as they api)roach the point, which the form of the saws requires. According to Vallisnieri, it is not the only use of this apparatus to form a back for the saws, he having discovered, between the component membranes, two canals, which he supposes are employed to conduct the eggs of the insect into the grooves which it has hollowed out for them. The teeth of a carpenter's saw, it may be remarked, are simple, whereas the teeth of the ovipositor-saw are themselves Portion of a Saw-Fly's comb-toothed rasp, and saw. denticulated with fine teeth. The latter, also, combines at the same time the properties of a saw and of a rasp or file. So far as we are aware, these two properties have, never been 172 Insect Architecture. combined in any of tlie tools of our carpenters. The rasping part of the ovipositor, however, is not constructed like our rasps, with short teeth thickly studded together, but has teeth almost as long as those of the saw, and placed con- tiguous to them, on the back of the instrument, resembling in their form and setting the teeth of a comb, as may be seen in the figure. Of course, such observations are conducted with the aid of a microscope. When a female saw-fly has selected the branch of a rose- tree, or any other, in which to deposit her eggs, she may be seen bending the end of her belly inwards, in form of a crescent, and protruding her saw, at the same time, to pene- trate the bark or wood. She maintains this recurved position so long as she works in deepening the groove ; but when she has attained the depth required, she unbends her body into a straight line, and in this position works upon the place lengthways, by applying the saw more horizontally. When she has rendered the groove as large as she wishes, the motion of the tendons ceases, and an egg is placed in the cavity. The saw is then withdrawn into the sheath for about two-thirds of its length, and at the same moment a sort of frothy liquid, similar to a lather made with soap, is dropped over the egg, either for the purpose of gluing it in its place or sheathing it from the action of the juices of the tree. She proceeds in the same manner in sawing out a second groove, and so on in succession, till she has deposited all her eggs, sometimes to the number of twenty -four. The grooves are usually placed in a line, at a small distance from one another, on the same branch ; but sometimes the mother- fly shifts to another, or to a different part of the branch, when she is either scared or finds it unsuittible. She com- monly, also, takes more than one day to the work, notwith- standing the superiority of her tools. Reaumur has seen a saw-fly make six grooves in succession, which occupied her about ten hours and a half. The grooves, when fijaished, have externally little elevation above the level of the bark, appearing like the puncture of a lancet in the human skin ; but in the course of a day or two Saw-Flies. 178 the part becomes first brown and then black, while it also becomes more and more elevated. This increased elevation is not owing to the growth of the bark, the fibres of which, indeed, have been destroyed by the ovipositor-saw, but to the actual growth of the egg ; for when a new-laid egg of the saw-fly is compared with one which has been several days enclosed in the groove, the latter will be found to be very considerably the Ir.rgcr. This growth of the egg is contrary to the analogy observable in the eggs of birds, and even of most other insects ; but it has its advantages. As it con- tinues to increase, it raises the bark more and more, and consequently widens, at the same time, the slit at the entrance; so that, v/hen the grub is hatched, it finds a passage ready for its exit. The mother-fly seems to be aware of this growth of her eggs, for she takes care to deposit them at such distances as may prevent their distm-bing one another by their development. Another species of saw-fly, with a yellow body and deep violet-coloured wings, which also selects the rose-tree, deposits her eggs in a different manner. Instead cf making a groove for each egg, like the preceding, she forms a large single groove, sufiicient for about two dozen eggs. These eggs are all arranged in pairs, forming two straight lines parallel to the sides of the branch. The eggs, however, though thus deposited in a common groove, are carefully kept Nest of egg 3 of Saw-fly, in rose-tree. each in its place ; for a ridge of the wood is left to prevent those on the right from touching those on the left — and not only so, but between eacii egg of a row a thin partition of wood is left, forming a shallow cell. The edges of this groove, it will be obvious, must be 174 Insect Architecture. fartlicr apart than those which only contain a single egg, and, in fact, the whole is open to inspection ; but the eggs are kept from falling out, both by the frothy glue before mentioned, and by the walls of the cells containing them. They were observed also, by Vallisnieri, to increase in size like the preceding. [In the middle of summer, plenty of these grooves may be seen, by looking at the under lid of leaf-stalks or delicate young twigs. Row upon row of the grooves are sometimes found, so the all-destructive power of the insects must indeed be great. The larvae, when full fed, dispose of them- selves in various ways. Those of the gooseberry-fly, for example (Nematus Itihesii), after they have stripped the bush of its leaves, either seek the ground or remain on the branches, and spin a series of cocoons, attaching them to each a a a, Saw-fly of the gooseberry [Nemxtas Rihesii, Stephens). l», its eggs on the nervures of a leaf, d d, the caterpillars eating, c, one ruUed up. /, one extended. branch by their ends. Those, therefore, who wish to destroy these little pests, must know both localities of the cocoons, or they will allow one half to escape while destroying the other,] Saw-Flies. 175 This insect has a flat yellow body and four pellucid wings, the two outer ones marked with brown on the edge. In April it issues from the pupa, which has lain under ground from the preceding September. The female of the gooseberry saw-fly does not, like some of the family, cut a groove in the brauch to deposit her eggs ; — " of what use, then," asks Eeaumur, " is her ovipositor-saw ?" In order to satisfy himself on this point, he introduced a pair of the flies under a bell-glass along with a branch bent from a red- cui'rrant bush, that he might watch the process. The female immediately perambulated the leaves in search of a place suited to her purpose, and passing under a leaf began to lay, depositing six eggs within a quarter of an hour. Each time she placed herself as if she wished to cut into the leaf with her saw ; but, upon taking out the leaf, the eggs appeared rather projecting than lodged in its substance. The cater- pillars are hatched in two or three weeks ; and they feed in company till after midsummer, frequently stripping both the leaves and fruit of an extensive plantation. The caterpillar has sis legs and sixteen prolegs, and is of a green colour mixed with yellow, and coveied with minute black dots raised like shagreen. In its last skin it loses the black dots and becomes smooth and yellowish white. The Caledonian Horticultural Society have published a number of plans for destroying these caterpillars. [Another remarkable mode of disposing of the pupa is shown in the accompanying illustration ; it represents the nest of an exotic saw-fly, named Deilocenes Ellisii. In this instance, the numerous larvfe unite in spinning for them- selves a common envelope of considerable strength ; it is seen as it appears when attached to the branch of a tree. The material of which it is composed is the tough silken fibre spun by the larvse of so many insects, which may be seen in perfection in the cocoons of the Microgaster. Two species of this curious group will be described in a future page. [By the side of the brauch is seen a diagram of the same nest, as it would appear in section. The irregularly angular cells are seen in the centre, and around them is the common 176 Insect Architecture. envelope composed of fibres. As may be seen from tlie upper figure, as soon as the insects bave attained tbeir perfect form, they gnaw tbeir way out of tbe cell and tbe covering also. Tbe insect is sbown as it appears wben flying. yH^ [We will conclude tbis chapter by a few remarks upon some exotic insects, whose nests are not only remarkable in tbeir form, but are valuable to tbe entomologist in affording grounds for tbe reception or rejection of certain familiar theories upon tbe subject of tbis volume — Insect Architecture. Several of these nests are of comparatively late discovery, and are therefore found in tbis work. [The curious series of cells sbown in the left-hand figure is made by a hymenopterous insect belonging to tbe genus Icaria, and the specimens from which tbe drawing was taken may be seen in the British Museum. They are made Icarias. 17' of a paper-like substance, mucli resembling in look tlie material of wbicli the common wasp builds its cells, but as tbey are exposed to tbe air, they are necessarily tougher and stronger than ordinary wasp cells, which are shielded from the elements. The insects belonging to this genus make nests of very diverse forms, some of which are stuck on leaves in a most ciu'ious manner, reminding the observer of the parasitic moUercoids that cover the stems and fronds of large seaweeds. Others, however, are not dependent upon leaves for their support, but stand out boldly from the branches to which they are fixed, supported entirely by a foot-stalk com- posed of the same material as the cells, though necessarily of a harder and more compact substance. [As many of these nests have been found in India, it is easy to trace the manner in which they were made. The mother insect began by kneading woody fibre into a paste, N 178 Insect Architecture. and making the footstalk of the future nest. One end of this footstalk is attached very strongly to the branch, and to the other end is fastened the first cell. As soon as the Icaria has made the first beginning of the cell, and raised — or rather lowered — the walls to a fourth or so of their complete dimen- sions, she inserts an egg into the yet imperfect cell, and adds to the walls while the egg is being hatched. Her next duty is, to add a second cell, and this is quickly followed by a third, all these cells being fastened to each other on three or four of their sides, leaving the others free and unattached. It is evident that by this mode of construction the cells nearest the branch must be the longest, because they are begun the soonest, and this will always be found to be the case. [Now, there is a point respecting which the attention of the reader must be specially solicited. On looking at the cells, he will see that they are partly cylindrical and partly angular, and may perhaps think that this fact goes towards proving that the hexagonal shape of bee cells is owing to mutual pressure, the outer sides of the cells being rounded, while the inner are angular. But, there are other cells in existence, built by allied insects, and formed in an analogous manner, and which are either angular or cylindrical, exactly according to the instinctive powers of the insect which built them. [On the right hand of the Icarian nest may be seen a singular-looking structure pendent at the end of a long foot- stalk. This is the nest of an insect called 3Iischocyttariis lahiatus, one of the PoUstidse. In this case, the cells are built so as to be defended from the rain by a sort of pent- house, over which all the raindrops would run, and so fall harmless to the ground. The cells of this insect are soft in texture, and are more cylindrical than angular, the angles being but very slightly marked. [Here, however, is the nest of an insect called JRaphigaster Guiniensis, which is built in a manner similar to that of the Icaria, the cells being closely in contact with each other. The material of which they are made is peculiarly soft. Saw -Flies. 179 something like very tliiu and flimsy grey paper. Conse- quently, they must press strongly upon each other, and we might reasonably expect to find that their angles ai"e well and boldly developed. But, instead of that, we find that they liave no angles at all, but remain smooth and rounded throughoiit their length, [Perhaps the most powerful argument against the equal pressure theory is to be found in the nest of a species of Icaria, which is shown in the accompanying illustration. [As may be seen by reference to the illustration, the material of which they are made is so soft, that they bend over by their own weight, and therefore we might expect to find that they would follow the shape of the Eaphigaster 180 Insect Arcliitecture. and tlie Mischocyttarus. But, we find that all the cells are boldly angular, and that the angles are just as sharp on the exterior of each cell as on the sides which cement the cells together. It is clear that the bold lines and decided angles of these cells cannot have been produced mechanically, and that they must have been intentionally formed by the insect architect. [One single cell, such as is here shown, is sufficient to overthrow the theory of "equal pressure," by which insects were deprived of all mechanical skill, and supposed to labour like so many animated machines, without caring or knowing anything about the work on which they were engaged. According to the equal pressui-e theory, each of these cells would have required six similar cells around it before it could have assumed the hexagonal form, and yet we find that a cell which is only connected with its neighbour by one side, has its other five sides angular, and with the angles boldly defined.] 181 CHAPTEB VIIL LEAF-ROLLING CATEEPILLAES. rPHE laboui's of tliose insect-architects, which we have -'- endeavoured to describe in the preceding pages, have been chiefly those of mothers to form a secure nest for their eggs, and the young hatched from them, during the first stage of their existence. But a much more numerous and not less ingenious class of architects may be found among the newly- hatched insects themselves, who, untaught by experience, and altogether unassisted by previous example, manifest the most marvellous skill in the construction of tents, houses, galleries, covert-ways, fortifications, and even cities, not to speak of subterranean caverns and subaqueous apartments, which no human art could rival. The caterpillars, which are familiarly termed leaf-rollers, are perfect hermits. Each lives in a cell, which it begins to construct almost immediately after it is hatched ; and the little structure is at once a house which protects the cater- pillar from its enemies, and a store of food for its subsist- ence, while it remains shut up in its prison. But the insect only devours the inner folds. The art which these cater- pillars exercise, although called into action but once, perhaps, in their lives, is perfect. They accomplish their purpose with a mechanical skill, which is remarkable for its sim- plicity and unerring success. The art of rolling leaves into a secure and immovable cell may not appear very difficult : nor would it be so if the caterpillars had fingers, or any parts which were equivalent to those delicate and admirable natural instruments with which man accomplishes his most elaborate works. And yet the human fingers could not roll a rocket-case of paper more regularly than the caterpillar rolls his house of leaves. A leaf is not a very 182 Insect Architecture. easy substance to roll. In some trees it is very brittle. It has also a natural elasticity, — a disposition to spring back if it be bent, — whicli is caused by the continuity of its threads, ur nervures. This elasticity is speedily overcome by the ingenuity with which the caterpillar works ; and the leaf is thus retained in its artificial position for many weeks, imder every variety of temperature. We will examine, in detail, how these little leaf-rollers accomplish their task. One of the most common as well as the most simple fabrics constructed by caterpillars, may be discovered during sum- mer on almost every kind of bush and tree. We shall take as examples those which are found on the lilac and on the oak. A small but very pretty chocolate-coloured moth, abundant Lilac-tree Moth. [Lozotania riteana, Stepheks ?) in every garden, but not readily seen, from its frequently alighting on the ground, which is so nearly of its own colour, Nest of a Lilac-leaf Roller. deposits its eggs on the leaves of the currant, the lilac, and of some other trees, appropriating a leaf to each egg. As Cate^inllars. 183 soou as the caterpillar is hatched, it begins to secure itself from birds and predatory insects by rolling up the lilac leaf into the form of a gallery, where it may feed in safety. Wc have repeatedly seen one of them when just escaped from the egg, and only a few lines long, fix several silk threads from one edge of a leaf to tlie other, or from the edge to the mid- rib; then going to the middle of the space, he shortened the threads by bending them with his feet, and consequently pulled the edges of the leaves into a circular form ; and he retained them in that position by gluing down each thread as he shortened it. In their younger state, those caterpillars seldom roll more than a small portion of the leaf ; but, when Another nest of Lilac-leaf Roller. farther advanced, they unite the two edges together in their \viiole extent, with the exception of a small opening at one end, by which an exit may be made in case of need. Another species of caterpillar, closely allied to this, rolls up the lilac leaves in a different form, beginning at the end of a leaf, and fixing and pulling its threads till it gets it nearly into the shape of a scroll of parchment. To retain 184 Insect Architecture. tliis form more securely, it is not contented, like the former insect, with threads fixed on the inside of the leaf; but has also recourse to a few cables which it weaves on the outside. Another species of moth, allied to the two preceding, is of Small green Oak-moth. (Tortrix viridana.) a pretty green colour, and lays its eggs upon the leaves of the oak. This caterpillar folds them up in a similar manner, but with this difiierence, that it works on the under surface of the leaf, pulling the edge downwards and backwards, instead of forwards and upwards. This species is very Nests of Oak-leaf-rolling Catei-pillars. abundant, and may readily be found as soon as the leaves expand. In June, when the perfect insect has appeared, by Caterpillars. 185 beating a brancli of an oak, a whole shower of these pretty green moths may be shook into the air. Among the leaf-rolling caterpillars, there is a small dark- brown one, with a black head and six feet, very common in gardens, on the currant-bush, or the leaves of the rose-tree {Lozotcenia rosana, Stephens). It is exceedingly destructive to the flower-buds. The eggs are deposited in the summer, and probably also in the autumn or in sj»ring, in little oval or circular patches of a green colour. The grub makes its apj)earance with the first opening of the leaves, of whose structure in the half-expanded state it takes advantage to construct its smnmer tent. It is not, like some of the other leaf-rollers, contented with a single leaf, but weaves together as many as there are in the bud where it may chance to have been hatched, binding theii- discs so firmly with silk, that all the force of the ascending sap, and the increasing growth of the leaves, cannot break through ; a farther expansion is of course prevented. The little inhabitant in the meanwhile banquets securely on the partitions of its tent, eating door- ways from one aj)artment into another, through which it can escape in case of danger or disturbance. The leaflets of the rose, it may be remarked, expand in nearly the same manner as a fan, and the operations of this ingenious little insect retain them in the form of a fan nearly shut. Sometimes, however, it is not contented with one bundle of leaflets, but by means of its silken cords unites all which spring from the same bud into a rain-proof canopy, imder the protection of which it can feast on the flower-bud, and prevent it from ever blowing. In the instance of the currant-leaves, the proceedings of the grub are the same ; but it cannot unite the plaits so smoothly as in the case of the rose leaflets, and it requires more labour, also, as the nervures, being stiff, demand a greater effort to bend them. When all the exertions of the insect prove unavailing in its endeavours to draw the edges of a leaf together, it bends them inwards as far as it can, and weaves a close web of silk over the open space between. 180 Insect Architecture. This is well exemplified in one of the commonest of our leaf- rolling caterpillars, which may be found as early as February on the leaves of the nettle and the white archangel {Lammm album). It is of a light dirty-green colour, spotted with black, and covered with a few hairs. In its young state it confines itself to the bosom of a small leaf, near the insertion of the leaf-stalk, partly bending the edges inwards, and covering in the interval with a silken curtain. As this sort of covering is not sufficient for concealment when the animal advances in growth, it abandons the base of the leaf for the middle, where it doubles up one side in a very secure and ingenious manner. Nest of the NetHe-leaf-roUing Caterpillar, We have watched this little architect begin and finish his tent upon a nettle in our study, the whole operation taking more than half an hour. (J. R.) He began by walking over the plant in all directions, examining the leaves sever- ally, as if to ascertain which was best fitted for his purpose by being pliable, and bending with the weight of his body. Having found one to his mind, he placed himself along the mid-rib, to the edge of which he secured himself firmly Avith the pro-legs of his tail ; then stretching his head to the edge of the leaf, he fixed a series of parallel cables betv^een it and the mid-rib, with another series crossing these at an acute angle. The position in which he worked was most remark- able, for he did not, as might have been supposed, spin his cables with his face to the leaf, but throwing himself on his back, which was turned towards the leaf, he hung with his whole weight by his first-made cables. This, by drawing them into the form of a curve, shortened them, and conse- quently pulled the edge of the leaf down towards the mid- Caterpillars. 187 rib. The weight of his body was not, however, the only- power which he emjiloyed ; for, using the terminal pro-legs as a point of sujiport, he exerted the whole muscles of his body to shorten his threads, and pull down the edge of the leaf. When he had di-awn the threads as tight as he could, he held them till he sjiun fresh ones of sufficient strength to re- tain the leaf in the bent j^osition into w hich he had pulled it. He then left the fii'st series to hang loose while he shortened the fresh-spun ones as before. This process was continued till he had worked down about an inch and a half of the leaf, as much as he deemed sufficient lor his habitation. This was the first part of the architectm-e. By the time he had worked to the end of the fold, he had brought the edge of the leaf to touch the mid-rib ; but it was only held in this position by a few of the last-spun threads, for all the first-spun ones hung loose within. Apparently aware of this, the insect protruded more than half of its body through the small aperture left at the end, and spun several bundles of threads on the outside precisely similar to those ropes of a tent which extend beyond the canvas, and are pegged into the ground. Unwilling to trust the exposui-e of his whole body on the outside, lest he should be seized by the first sand-wasp (odi/nerus) or sparrow which might descry him, he now withdrew to complete the internal portion of his dwelling, where the threads were hanging loose and dis- orderly. For this purpose he turned his head about, and proceeded precisely as he had done at the beginning of his task, but taking care to s^iin his new thi-eads so as to leave the loose ones on the outside, and make his apartment smooth and neat. When he again reached the opposite end, he constructed there also a similar series of cables on the out- side, and then withdi-ew to give some final touches to the interior. It is said by Kirby and Spence,* that w'hen these leaf- rolling insects find that the larger nervures of the leaves are so strong as to prevent them from bending, they " weaken it by gnawing it here and there half through." We have never * Introd., vol. i. p. i'u. 188 Insect Architecture. observed the circumstance, tliougli we liave witnessed tlie process in some hundreds of instances ; and we doubt the statement, from the careful survey which the insect makes of the capabilities of the leaf before the operation is begun. If she found upon examination that a leaf would not bend, she would reject it, as we have often seen happen, and pass to another, (J. E.) A species of leaf-roller, of the most diminutive size, merits particular mention, although it is not remarkable in colour or figure. It is without hair, of a greenish-white, and has all the vivacity of the other leaf-rollers. Sorrel is the plant on which it feeds ; and the manner in which it rolls a portion of the leaf is very ingenious. The structure which it contrives is a sort of conical pyramid, composed of five or six folds lapped round each other. From the position oi this little coue the caterpillar Leaf-rolling Caterpillars of the Sorrel. has other labours to perform, beside that of rolling the leaf. It first cuts across the leaf, its teeth acting as a pair of scissors ; but it does not entirely detach this segment. It rolls it up very gradually, by attaching threads of silk to the plane surface of the leaf, as we have before seen , and then, having cut in a dijfferent direction, sets the cone upright, Caterpillars. 189 by weaving other threads, attached to the centre of the roll and the plane of the leaf, upon which it throws the weight of its body. This, it will bo readily seen, is a somewhat complicated effort of mechanical skill. It has been minutely described by M. Reaumur ; but the preceding rei)resentation will perhaps make the process clearer than a more detailed account. This caterpillar, like those of which we have already spoken, devours all the interior of the roll. It weaves, also, in the interior, a small and thin cocoon of white silk, the tissue of which is made compact and close. It is then transformed into a chrysalis. The caterpillars of two of our largest and handsomest butterflies, the painted lady (Cynthia cardui, Stephens), and the admiral, or Alderman of the London fly-fanciers Jfeits of tlie Hesperia malvw, with Oiterpillar, Chrysalis, and Butterflies. (Vanessa atalanta), are also leaf-rollers. The first selects the leaves of the great spear-thistle, and sometimes those of the btemless or star-thistle, which might be supposed 190 Insect Architecture. rather difficult to bend ; but tbe caterpillar is four times as large and strong as those which we have been hitherto de- scribing. In some seasons it is plentiful ; in others it is rarely to be met with : but the admiral is seldom scarce in any part of the country ; and by examining the leaves of nettles which appear folded edge to edge, in July and August, the caterpillar may be readily found. Another butterfly (Hesperia malvce) is met with on dry banks where mallows grow, in May, or even earlier, and also in August, but is not indigenous. The caterpillar, which is grey, with a black head, and four sulphur-coloured spots on the neck, folds around it the leaves of the mallow, upon which it feeds. There is nothing, however, pecu- liai'ly diiferent in its proceedings from those above de- scribed ; but the care with which it selects and rolls up one of the smaller leaves, when it is about to be transformed into a chrysalis, is worthy of remark ; it joins it, indeed, so completely round and round, that it has somewhat the resemblance of an egg. Within this green cell it lies secure, till the time arrives when it is ready to burst its cerements, and trust to the quickness of its wings for protection against its enemies. Among the nests of caterpillars which roll up parcels of leaves, we know none so well contrived as those which are foimd upon willows and a species of osier. The long and narrow leaves of these plants are naturally adapted to be adjusted parallel to each other ; for this is the direction which they have at the end of each stalk, when they are not entirely developed. One kind of small smooth cater- pillar {Tortrix cMorana), with sixteen feet, the under part of which is brown, and streaked with white, fastens these leaves together, and makes them up into parcels. There is nothing particularly striking in the mechanical manner in which it constructs them. It does precisely what we shoiild do in a similar case : it winds a thread round those leaves which must be kept together, from a little above their ter- mination to a very short distance from their extreme point ; and as it finds the leaves almost constantly lying near each Caterpillars. 191 other, it has little difficulty in bringing them together, as is sho\\Ti in the following cut, a. The prettiest of these parcels arc those which are made upon a kind of osier, the borders of whose leaves sometimes form columnar bundles before they become developed. A section of these leaves has the appearance of filigree-work (see h). Nest of WiUow-leaf Roller. A caterpillar which feeds upon the willow, and whose singular attitudes have obtained for it the trivial name of Ziczac, also constructs for itself an arbour cf the leaves, by drawing them together in an ingenious manner, M. Roescl* has given a tolerable representation of this nest, and of the caterpillar. The caterpillar is fouud in June ; * Roesol, cl. ii,, Pap. Nocturn., tab. sx. fig. 1, 2, 3, 4, 5, 6, 192 Insect Architecture. and the moth (Notodonta ziczac) from May to July in the following year (see cut, p. 151). Beside those caterpillars which live solitary in the folds of a leaf, there are others which associate, emijloying their united powers to draw the leaves of the plants they feed upon into a covering for their common protection. Among these we may mention the caterpillar of a-rimall butterfly, the plantain or Glanville fritillary (Melitea cinxia), which is very scarce in this countiy. Although a colony of these caterpillars is not numerous, seldom amounting to a hundred individuals, the place which Ziczac Caterpillar and Nest. they have selected is not hard to discover. Their abode may be seen in the meadow in form of a tuft of herbage covered with a white web, which may readily be mistaken, at first view, for that of a spider, but closer inspection soon corrects this notion. It is, in fact, a sort of common tent. Cat^pillars. 193 in which the whole brood lives, eats, and undergoes the usual transformations. The shape of this teut, for the most part, approaches the pyi'amidal, though that depends much upon the natural growth of the herbage which composes it. The interior is divided into comjiartments formed by the union of several small tents, as it were, to which otiiers have been from time to time added according to the necessities of the community. When they have devoured all the leaves, or at least those which are most tender and succulent, they abandon their fii'st camj), and construct another contiguous to it under a tuft of fi-esh leaves. Several of these encampments may sometimes be seen within the distance of a foot or two, when they can find plantain (Plantago lanceolata) fit for their piu-pose ; but though they prefer this plant, they content themselves with grass if it is not to be procm'ed. When they are about to cast their skins, but particularly when they perceive the approach of winter, they construct a more durable apartment in the interior of their principal tent. The ordinary web is thin and semi-ti'ansparent, per- mitting the leaves to be seen thi-ough it ; but their winter canvas, if we may call it so, is thick, strong, and quite opaque, forming a sort of circular hall without any par- tition, where the whole community lie coiled uj} and huddled together. Early in spring they issue forth in search of fresh food, and again construct tents to protect them from cold and rain, and from the mid-day sun. M. Keaiunur found upon trial, that it was not only the caterpillars hatched from the eggs of the same mother v'hich would unite in constructing the common tent ; for different broods, when put together, worked in the same social and harmonious manner. We ourselves ascertained, during the present summer (1829), that this principle of sociality is not confined to the same species, nor even to the same genus. The experiment which we tried was to confine two broods of different species to the same branch, by placing it in a glass of water to prevent their escape. o 194 Insect Architecture. The caterpillars wliich we experimented on were several broods of the brown-tail moth (Porthesia auriflua) and the lackey {Clisiocamjpa neustria). These we found to work with as much industry and harmony in constructing the common tent as if they had been at liberty on their native trees ; and when the lackeys encountered the brown-tails they manifested no alarm nor uneasiness, but passed over the backs of one another, as if they had made only a portion of the branch. In none of their operations did they seem to be subject to any discipline, each individual appearing to work, in perfecting the structure, from individual instinct, in the same manner as was remarked by M. Huber in the case of the hive-bees. In making such experiments, it is obvious that the species of caterpillars experimented with must feed upon the same sort of plant.* (J. E.) The design of the caterpillars in rolliug up the leaves is not only to conceal themselves from birds and predatory insects, but also to protect themselves from the cuckoo- flies, which lie in wait in every quarter to deposit their eggs in their bodies, that their progeny may devour them. Their mode of concealment, however, though it aj)pear to be cunningly contrived and skilfully executed, is not always successful, their enemies often discovering their hiding-place. We happened to see a remarkable instance of this last summer (1828), in the case of one of the lilac cateri^illars which had changed into a chrysalis within the closely-folded leaf. A small ichneumon, aware it should seem of the very spot where the chrysalis lay within this leaf, was seen boring through it with her ovipositor, and introducing her eggs tlirough the punctures thus made into the body of the dormant insect. We allowed her to lay all her eggs, about six in number, and then put the leaf under an inverted glass. In a few days the eggs of the cuckoo-fly were hatched, the grubs devoured the lilac chrysalis, and finally changed into pupee in a case of yellow silk, and into perfect insects like their parents. (J. R.) * See p. 100. 195 CHAPTER IX. INSECTS FORMING HABITATIONS OF DETACHEB LEAVES. npHE habitations of the insects which we have just described -■- consist of growing leaves, bent, rolled, or pressed to- gether, and fixed in their positions by silken threads. But there are other habitations of a similar kind, which are con- structed by cutting out and detaching a whole leaf, or a portion of a leaf We have already seen how dexterously the uphol- sterer-bees cut out small parts of leaves and petals with their mandibles, and fit them into their cells. Some of the cater- pillars do not exhibit quite so much neatness and elegance as the leaf-cutting bees, though their structures answer all the purposes intended ; but there are others, as we shall presently see, that far excel the bees, at least in the delicate minutite of their workmanship. We shall first advert to those structures which are the most simple. Not far from Longchamps, in a road through the Bois de Boulogne, is a large marsh, which M. Eeaumur never observed to be in a dry state even dm-ing summer. This marsh is surrounded with very lofty oaks, and abounds with pondweed, the water-plant named by botanists potamogeton. The shining leaves of this j)lant, which are as large as those of the laurel or orange-tree, but thicker and more fleshy, are spread upon the surface of the water. Having pulled up several of these about the middle of June, M. Eeaumur observed, beneath one of the first which he examined, an elevation of an oval shape, which was formed out of a leaf of the same plant. He carefully examined it, and discovered that threads of silk were attached to this elevation. Break- ing the threads, he raised up one of the ends, and saw a cavity, in which a caterpillar (Hydrocampa potamogcta) was lodged. 196 Insect Architecture. An indefatigable observer, such as M. Eeaumur, would naturally follow up this discovery ; and he has accordingly given us a memoir of the pondweed tent-maker, distinguished by bis usual minute accuracy. In order to make a new habitation, the caterpillar fastens itself on the under side of a leaf of the Pofatnogeton. With its mandibles it pierces some part of this leaf, and afterwards gradually gnaws a curved line, marking the form of the piece which it wishes to detach. When the caterpillar has cut off, as from a piece of cloth, a patch of leaf of the size and shape suited to its purpose, it is provided with half of the materials requisite for making a tent. It takes hold of this piece by its mandibles, and conveys it to the situation on the under side of its own or another leaf, whichever is found most appropriate. It is there disposed in such a manner that the under part of the patch — the side which was the under part of the entire leaf — is turned towards the under part of the new leaf, so that the inner walls of the cell or tent are always made by the under part of two portions of leaf. The leaves of the potamogeton are a little concave on the under side ; and thus the caterpillar produces a hollow cell, though the rims are united. The caterpillar secures the leaf in its position by threads of white silk. It then weaves in the cavity a cocoon, which is somewhat thin, but of very close tissue. There it shuts itself up, to appear again only in the form of the perfect insect, and is soon transformed into a chrysalis. In this cocoon of silk no point touches the water ; whilst the tent of leaves, lined with silk, has been constructed underneath the water. This fact proves that the cateri^illar has a particu- lar art by which it repels the water from between the leaves. When the caterpillar, which has thus conveyed and disposed a patch of leaf against another leaf, is not ready to be transformed into a chrysalis, it aj)plies itself to make a tent or habitation which it may carry everywhere about with it. It begins by slightly fixing the piece against the perfect leaf, leaving intervals all round, between the piece and leaf, at which it may project its head. The piece which it has Cypress-Spurge Caterpillar. 197 fixed serves as a model for cutting out a similar piece in the other leaf. The caterpillar puts them accurately together, except at one end of the oval, where an opening is left for the insect to project its head through. When the caterpillaj- is inclined to change its situation, it draws itself forward by means of its scaly limbs, riveted upon the leaf. The mem- braneous limbs, which are riveted against the inner sides of the tents, oblige it to follow the anterior part of the body, as it advances. The caterpillar, also, puts its head out of the tent every time it desii'es to eat. There is found on the common chickweed (Stellaria media), towards the end of July, a middle-sized smooth green cater- pillar, having three bro\\Ti spots bordered with white on the back, and six legs and ten pro-legs, whose architectiu-e is worthy of observation. When it is about to go into chrysalis, towards the beginning of August, it gnaws off, one by one, a number of the leaves and smaller twigs of the chickweed, and adjusts them into an oval cocoon, somewhat rough and un- finished externally, but smooth, uniform, and finely tapestried with white silk within. Here it undergoes its transform- ation securely, and, when the period of its pupa trance has expired in the following July, it makes its exit in the form of a yellowish moth, with several brown spots above, and a brown baud on each of its four wings below. It is also fur- nished with a sort of tail. On the cypress-spm-ge (Eiiphorbia cyparissias), a native woodland plant, but not of very common occm-rence, may be found, towards the end of October, a caterpillar of a middle size, sparely tufted with haii-, and striped with black, white, red, and brown. The leaves of the plant, which are in the form of short narrow blades of grass, are made choice of by the caterpillar to construct its cocoon, which it does with great neatness and regularity, the end of each leaf, after it has been detached from the plant, being fixed to the stem, and the other leaves placed parallel, as they are successively added. The other ends of all these are bent inwards, so as to form a uniformly rounded oblong figure, somewhat larger at one end than at the other. 198 Insect Architecture. A caterpillar which builds a very similar cocoon to the last-mentioned may be found uj^on a more common plant — the yellow snap-dragon or toad-flax {Antirrhinum linaria) — which is to be seen in almost every hedge. It is somewhat shaped like a leech, is of a middle size, and the prevailing colom- pearl-grey, but striped with yellow and black. It spins up about the beginning of September, forming the outer coating of pieces of detached leaves of the plant, and sometimes of whole leaves placed longitudinally, the whole disposed Avith great symmetry and neatness. The moth appears in the following June. Cj'press-Spurge Caterpillar- (^cro«!/cia Euphrasia)— mih a Cocoon, on a branch. It is worthy of remark, as one of the most striking instances of instinctive foresight, that the caterpillars which build structures of this substantial description are destined to lie much longer in their chrysalis trance than those which spin merely a flimsy web of silk. For the most part, indeed, the latter undergo their final transformation in a few weeks ; while the former continue entranced the larger portion of a year, appearing in the perfect state the summer after their architectural labours have been completed. (J. R.) This is a remarkable example of the instinct which leads these little creatures to act as if under the dictates of prudence, and with a perfect knowledge of the time, be it long or short, which wiU elapse before the last change of the pupa takes place. That the caterpillar, while weaving its cocoon Moss-Building Cateryillar. 199 and preparing to assume the pupa state, exercises any reflec- tive faculties, or is aware of what is about to occur relative to its own self, we cannot admit. It enters upon a work of which it has had no previous experience, and which is per- formed, as far as contingencies allow, in the same manner by every caterpillar of the same species. Its labours, its mode of carrying them on, and the very time in which they are to be commenced, are all pre-appointed ; and an in- stinctive impulse urges and guides ; and with this instinct its organic endowments are in precise harmony ; nor does instinct ever impel to labours for which an animal is not provided. " The same wisdom," says Bonnet, " which has constructed and arranged with so much art the various organs of animals, and has made them concur towards one determined end, has also provided that the different opera- tions which are the natural results of the economy of the animal should concur towards the same end. The creature is directed towards his object by an invisible hand ; he exe- cutes with precision, and by one effort, those works which we so much admire ; he appears to act as if he reasoned, to return to his labour at the proper time, to change his scheme in case of need. But in all this he only obeys the secret influence which di'ives him on. He is but an instrument which cannot judge of each action, but is wound up by that adorable Intelligence, which has traced out for every insect its proper labours, as he has traced the orbit of each planet. ^^ hen, therefore, I see an insect working at the construction of a nest, or a cocoon, I am impressed with respect, because it seems to me that I am at a spectacle where the Supreme Artist is hid behind the curtain."* There is a small sort of caterpillar which may be found on old walls, feeding upon minute mosses and lichens, the proceedings of which are well worthy of attention. They are similar, in appearance and size, to the caterpillar of the small cabbage-butterfly (Pontia rapce), and are smooth and bluish. The material which they use in building their cocoons is composed of the leaves and branchlets of green * Contemplation de la Kature, part xv. chap. 38. 200 Insect Architecture. moss, which they cut into suitable pieces, detaching at the same time along with them a portion of the earth in which they grow. They arrange these upon the walls of their building, with the moss on the outside, and the earth on the inside, making a sort of vault of the tiny bits of green moss turf, dug from the surface of the wall. So neatly, also, are the several pieces joined, that the whole might well be sup- posed to be a patch of moss which had grown in form of an oval tuft, a little more elevated than the rest growing on the wall. When these caterpillars are shut up in a box with some moss, without earth, they construct with it cells in form of a hollow ball, very prettily plaited and interwoven. In May last (1829), we found on the walls of Greenwich Park a great number of caterpillars, whose manners bore some resemblance to those of the grub described by M. Keaumur. (J. E.) They were of middle size, with a dull- orange stripe along the back; the head and sides of the body black, and the belly greenish. Their abodes were constructed with ingenuity and care. A caterpillar of this sort appears to choose either a part where the mortar con- tains a cavity, or it digs one suited to its design. Over the opening of the hollow in the mortar it builds an arched wall, so as to form a chamber considerably larger than is usual with other architect caterpillars. It selects grains of mortar, brick, or lichen, fixing them, by means of silk, firmly into the structure. As some of these vaulted walls were from an inch to an inch and a half long, and about a third of an inch wide and deep, it may be well imagined that it would require no little industry and labour to complete the Moss-huilding Caierjnllar. 201 work ; yet it does not demand more than a few hours for the insect to raise it from the foundation. Like all other insect architects, this caterpillar uses its own body for a measm-ing-rulc, and partly for a mould, or rather a block or centre to shape the walls by, ciu-ving itself round and round concentrically with the ai-ch which it is building. We afterwards found one of these caterpillars, which had dug a cell in one of the softest of the bricks, covering itself on the outside with an arched wall of brick-dust, cemented with silk. As this brick was of a bright-red coloiu', we were thereby able to ascertain that there was not a particle of lichen employed in the structui'e. The neatness mentioned by Reaumur, as remarkable in his moss-building caterpillars, is equally observable in that which we have just described ; for, on looking at the surface of the wall, it would be impossible for a person unacquainted with those structures to detect w^here they were placed, as they are usually, on the outside, level with the adjoining brick-work ; and it is only when they are opened by the entomologist, that the little architect is perceived lying snug in his chamber. If a portion of the wall be thus broken down, the caterpillar immediately commences repairing the breach, by piecing in bits of mortar and fragments of lichen, till we can scarcely distinguish the new portion from the old. 202 Insect Architecture, CHAPTEB X. CADDIS-WOEMS AKD CAEPBNTER-CATEEPILLAES. npHEEE is a very interesting class of grubs whicli live under -*- water, where they construct for themselves moveable tents of various materials as their habits direct them, or as the substances they require can be conveniently procured. Among the materials used by these singular grubs, well- known to fishermen by the name of caddis-worms, and to naturalists as the larvcB of the four-winged flies in the order Triclwptera of Kirby and Spence, we may mention sand, stones, shells, wood, and leaves, which are skilfully joined and strongly cemented. One of these grubs forms a pretty case of leaves glued together longitudinally, but leaving an aperture sufficiently large for the inhabitant to put out its head and shoulders when it wishes to look about for food. Leaf Nest of Caddis-Worm. Another employs pieces of reed cut into convenient lengths, or of grass, straw, wood, &c., carefully joining and cementing each piece to its fellow as the work proceeds; and he frequently finishes the whole by adding a broad piece longer Reed Nest of Cadd s-'\Vorm. than the rest to shade his door-way overhead, so that he may not be seen from above. A more laborious structure is reared by the grub of a beautiful caddis-fly (Phryganea), Caddis- Worms. 203 wliich weaves together a group of the leaves of aquatic plants into a roundish ball, and in the interior of this forms a cell for its abode. The following figure from Roesel will give a more precise notion of this structure than a lengthened description. Another of these aquatic architects makes choice of the tiny shells of young fresh- water mussels and snails (Planorhis), to form a moveable grotto ; and as these little shells are for the most part inhabited, he keeps the poor animals close Shell Nests of Caddis- Worms, prisoners, and drags them without mercy along with him. These grotto-building grubs are by no means uncommon in ponds ; and in chalk districts, such as the country about Woolwich and Gravesend, they are very abundant. One of the most surprising instances of their skill occurs in the structures of which small stones are the principal material. The problem is to make a tube about the width 204 Insect Architecture. of the liollow of a wheat straw or a crow-quill, and equally smooth and uniform. Now the materials being small stones full of angles and irregularities, the difficulty of performing this problem will appear to be considerable, if not insur- mountable : yet the little architects, by patiently examining their stones and turning them round on every side, never fail to accomplish their plans. This, however, is only part Stone Nest of Caddis-Worm. of the problem, which is complicated with another condition, and which we have not found recorded by former observers, namely, that the under-surface shall be flat and smooth, without any projecting angles which might impede its pro- gress when dragged along the bottom of the rivulet where it resides. The selection of the stones, indeed, may be ac- counted for, from this species living in streams where, but for the weight of its house, it would to a certainty be swept away. For this j)urj)ose, it is probable that the grub makes choice of larger stones than it might otherwise want ; and therefore also it is that we frequently find a case comj)osed of very small stones and sand, to which, when nearly Sand Nost balanced with a Stone. finished, a large stone is added by way of ballast. In other instances, when the materials are found to possess too great specific gravity, a bit of light wood, or a hollow straw, is added to buoy up the case. Nest of Caddis- Worm balanced with Straws. It is worthy of remark, that the cement, used in all these Caddis-Worms. 205 cases, is superior to pozzolana * in standing water, in wliicli it is indissoluble. The grubs tbomselvcs are also admirably adapted for their mode of life, the portion of their bodies which is always enclosed in the case being soft like a meal- worm, or garden-caterpillar, while the head and shoulders, which are for the most part projected beyond the door-way in search of food, are firm, hard, and consequently less liable to injury than the protected portion, should it chance to be exposed. We have repeatedly tried experiments with the inha- bitants of those aquatic tents, to ascertain their mode of building. We have deprived them of their little houses, and fm-nished them with materials for constructing new ones, watching their proceedings from their laying the first stone or shell of the structure. They woi'k at the commence- ment in a very clumsy manner, attaching a great number of chips to whatever materials may be within theii* reach with loose threads of silk, and many of these they never use at all in their perfect building. They act, indeed, much like an imskilful workman trying his hand before committing himself upon an intended work of difficult execution. Their main intention is, however, to have abundance of materials within reach : for after their dwelling is fairly begun, they shut themselves up in it, and do not again protrude more than half of their body to procure materials ; and even when they have dragged a stone, a shell, or a chip of reed within building reach, they have often to reject it as unfit. (J. E.) [We have here some examples of the latter kind of nest, i. e., those habitations which are made of stones and shells. Beginning at the upper left-hand figure, we find one that is made of moderately-sized stones cemented together in a way that reminds the observer of the manner in which a builder forms irregular stones into a wall. Next to it is another, in which the stones are larger and narrower, and are arranged much as some of the caddis-worms arrange pieces of stick and straw. * A cement prepamd of volcanic earth, or lava. 206 Insect Architedure. In the second, and on the left-hand side, is a very long and simple tube, made of a grass stem, and balanced by three little sticks attached to its centre. The next figure represents a number of sand-tubes attached to each other. These are built up laboriously of single particles of sand, and are remarkable for their peculiar horn-like shape, the tube having the same regular curve as the horn of an ox or antelope, and tapering gradually from the base to the top. A somewhat similar tube, but of larger size, is shown in the right-hand figure. Any one who wishes to see one of these creatures rebuild its house can do so by carefully removing it from its tube, and supplying it with fresh material. Very great care must be taken in the removal, as the grub is easily damaged, and it holds so tightly to the tube with a pair of pincers at the end of its body, that it must rather be coaxed than driven out. If desirable, they can be made to build their new houses Carpenter- Cater pilla vs. 207 of most singular materials. A ladj, Miss Smcc, was very successful iu a series of experiments wliicli she made with these insects, forcing them to make tubes of different colours and patterns, by supplying them with colom'ed sand, pieces of stained glass of various hues, gold dust, and similar materials. Although there was scarcely any material which they woidd not use, they seemed to consider a certain amount of angularity as essential, and rejected any object, such as a bead, of which the surface was perfectly rounded, while they would accept the same, if it were broken or indented. When the caddis-grub has ceased from feeding, and is about to pass into the perfect stage, it spins over the mouth of the tube a strong silken web. This web is made in quite a pretty pattern, and being woven with rather wide meshes, it allows the water to flow through the tube while it pre- vents any aquatic foes fi.'om penetrating and destroying the pupa. The remaining figures of the illustration represent tubes, around which are built a quantity of small shells. Generally, stones are mixed with the shells ; but in some cases, shells seem to be almost the only material.] Caepenter-Cateepillars. Insects, though sometimes actuated by an instinct ap- parently blind, unintelligent, or unknown to themselves, manifest in other instances a remarkable adaptation of means to ends. We have it in our power to exemplify this in a striking manner by the proceedings of the cater- pillar of a goat-moth (Cossus ligniperda) which we kept till it underwent its final change. This caterpillar, which abounds in Kent and many other parts of the island, feeds on the wood of willows, oaks, poplars, and other trees, in which it eats extensive galleries ; but it is not contented with the protection afforded by these galleries during the colder months of winter, before the arrival of which it scoops out a hollow in the tree, if it do not find one ready prepared, sufficiently large to contain its 208 1 used A rch itectu re . body in a bent or somewhat coiled-np position. On sawing off a portion of^ an old poplar in the winter of 1827, we found such a cell with a caterpillar coiled up in it. Caterpillar of Goat-Moth in a Willow Tree. It had not, however, been contented with the bare walls of the retreat which it had hewn out of the tree, for it had lined it with a fabric as thick as coarse broadcloth, and equally warm, composed of the raspings of the wood scooped Maimer Nest of the Goat-Caievpillar. out of the cell, united with the strong silk which every species of caterpillar can spin. In this snug retreat our caterpillar, if it had not been disturbed, would have spent the winter without eating ; but upon being removed into a Goaf -Moth. 201) warm room and placed under a glass along with some pieces of wood, which it might eat if so inclined, it was roused for a time from its dormant state, and began to move about. It was not long, however, in constructing a new cell for itself, no less ingenious than the former. It either could not gnaw into the fir plank, where it was now placed with a glass above it, or it did not choose to do so ; for it left it untouched, and made it the basis of the edifice it began to construct. It formed, in fact, a covering for itself precisely like the one from which we had dislodged it, — composed of raspings of wood detached for the purpose from what had been given it as food, the largest piece of which was employed as a substantial covering and protec- tion for the whole. It remained in this retreat, motionless, and without food, till revived by the warmth of the ensuing- spring, when it gnawed its way out, and began to eat vora- ciously, to make up for its long fast. These caterpillars are three years in arriving at their final change into the winged state ; but as the one just mentioned was nearly full grown, it began, in the month of May, to prepare a cell, in which it might undergo its metamorphosis. Whether it had actually improved its skill in architecture by its previous experience we will not undertake to say, but its second cell was greatly superior to the first. In the first there was only one large piece of Nest of Goat-Moth. — Figured from specimen, and raised to show the Pupa. wood employed ; in the second, two pieces were placed iu such a manner as to support each other, and beneath the 210 Insect Architecture. angle thus formed an obloug structure was made, comj)osed, as before, of wood-raspings and silk, but much stronger in texture than the winter cell. In a few weeks (four, if we recollect aright) the moth came forth. (J. E.) [I have now before me a series of three cocoons, made by one caterpillar of the goat-moth, showing its increase in size during the three years that it remained in the larval state. They were found in an old willow tree, and occupied different parts of the same burrow. The ravages which a goat-moth caterpillar can make in a tree are almost incredible to those who have not seen the long and tortuous burrows which the insect will construct, burrows which at first are small and insignificant, but which afterwards become large enough to admit a man's finger. [Sometimes the tunnel runs just under the bark, and sometimes it goes straight towards the centre of the tree ; and no small labour is required before it can be fully traced. Still, the result is worth the labour, for it is most inter- esting to trace the creature through its whole existence, from the tiny hole which it made soon after its exit from the egg, to the large aperture through which it emerged as a moth. The whole of the tunnel is strongly imbued with the peculiar and unpleasant odour which has given to the goat-moth its popular name ; and the scent is so per- sistent, that it adheres to the fingers which have touched the sides of the tunnel, and can scarcely be removed even by repeated washings. [The moth itself is a well-known insect, though rarely seen except by night. It is large, brown, round bodied ; the wings are covered with a soft and downy clothing, which strongly reminds the observer of the plumage of an owl.] A wood-boring caterpillar, of a sj)ecies of moth much rarer than the preceding {^^gcria asiliformis, Stephens), exhibits great ingenuity in constructing a cell for its meta- morphosis. We observed above a dozen of them during this summer (1829) in the trunk of a poplar, one side of which had been stripped of its bark. It was this portion of the trunk which all the cater^^illars selected for their Puss-Moth. 211 final retreat, uot one having beeu observed where the tree was covered with bark. The ingenuity of the little architect consisted in scooping its cell almost to the very siuface of the wood, leaving only an exterior covering of unbroken wood, as thin as writing-paper. Previous, therefore, to the chrysalis making its way through this feeble barrier, it could not have been suspected that an insect was lodged under the smooth wood. We observed more than one of these in the act of breaking through this covering, within which there is, besides, a round moveable lid of a sort of bro\Mi wax. (J. E.) Xiii'i ^v I.arva of -tgt-ria. Another architect caterpillar, frequently to be met with in July on the leaves of the willow and the poplar, is, in the fly-state, called the puss-moth (Cerura vinnla). The caterpillar is produced from brown-coloured shining eggs, about the size of a pin's head, which are deposited — one, 212 Insect Architecture. two, or more together — on tlie upjier surface of a leaf. In tlie coui'se of six or eiglit weeks (during which time it casts its skin thrice) it arrives at its full growth, when it Eggs of the Puss-3Ioth. is about as thick, and nearly as long, as a man's thumb, and begins to prepare a structure in which the pupa may sleep securely diu"ing the winter. As we have, oftener than once, seen this little architect at work, from the foundation till the completion of its edifice, we are thereby enabled to give the details of the process. The puss, it may be remarked, does not depend for pro- tection on the hole of a tree, or the shelter of an overliaug- ing branch, but upon the solidity and strength of the fabric which it rears. The material it commonly uses is the bark of the tree upon which the cell is constructed ; but when this cannot be procured, it is contented to employ whatever analogous materials may be within reach. One which we had shut up in a box substituted the marble paper it was lined with for bark, which it could not procure.* With * It is justly remarked by Reaumur, that when caterpillars are left at liberty among their native plants, it is only by luclty chance they can be ob- served building their cocoons, because the greater number abandon the plants upon which they have been feeding, to spin up in places at some distance. In order to see their operations, they must be kept in confinement, particularly in boxes with glazed dooi-s, where they may be always under the eye of the natu- ralist. In such circumstances, however, we may be ignorant what building materials we ought to provide them with for their structures. A red cater- pillar, with a few tufts of hair, which Reaumur found in July feeding upon the flower bunches of the nettle, and refusing to toucli the leaves, began in a few days to prepare its cocoon, by gnawing the paper lid of the box in which it was placed. This, of course, was a material which it could not have procured in the fields, but it was the nearest in properties that it could procure ; for, though it had the leaves and stems of nettles, it never used a single fragment of either. When Iieaumur found that it was likely to gnaw through the paper Puss-Moth. 213 silk it first wcvc a thiu web round the edges of the place which it marked out for its edifice , theu it rau several threads in a spare manner from side to side, and Irom end to end, but very irregularly in point of arrangement ; these were intended for the skeleton or frame- work of the build- ing "When this outline was finished, the next step was to strengthen each thread of silk by adding several (sometimes Rudiments of ihe Cell of the Puss-Moth. six or eight) parallel ones, all of which were then glued together into a single thread, by the insect running its mandibles, charged with gluten, along the line. The meshes, or spaces, which were thus widened by the com- pression of the parallel threads, were immediately filled up with fresh threads, till at length only very small spaces were left. It was in this stage of the operation that the paper came into requisition, small portions of it being gnawed off' the box and glued into the meshes. It was not, however, into the meshes only that thf bits of paper were inserted ; for the whole fabric was in the end thickly studded over with them. In about half a day from the first thread of the frame-work being spun the building was completed. It was at first, however, rather soft, and yielded to slight pressure with the finger ; but as soon as it became thoroughly dry, it was so hard t|iat it could with lid of the box, and might effect its escape, he furnished it with bits of rumpled paper, fixed to the lid by means of a pin -, and these it chopped down into such pieces as it judged convenient for its structure, which it took a day to complete. The moth appeared four weeks after, of a biowmsh-black colour, mottled with white, or rather grey, in the manner of lace. Bonnet also mentions more than one instance in which he observed cater- pillai-s making use of paper, when they could not procure other materials. 214 Insect Architecture. difficulty be j)eiiGtrated with tlie point of si penknife. (J. R.) [ One puss-motli larva, wliicli I reared, made its nest in a rather curious manner. After it had ceased feeding it had been placed on a marble mantelpiece under a glass tumbler, K°"C£^^C&;-:>- Cell built by the Larva of the Puss-.Mulh. as a temporary residence until a more appropriate dwelling could be found for it. But its instincts urged it to make its nest without delay, and it accordingly set to work, and spun itself up in a cocoon composed entirely of its own silk, neither the glass tumbler or the mantelpiece affording it any material with which to harden the walls of its dwelling. [Consequently, the texture of the cocoon was of a rather singular nature. The silken threads had been fused to- gether so as to form a translucent cocoon, looking as if it had been made of gelatine, and being nearly equally' trans- parent, the chrysalis being plainly visible through its walls. The cocoon was thin and elastic, as if it had been made of very thin horn ; and it was so tightly fixed to the mantel- piece as well as to the tumbler, that it could not be removed without damage. The moth suffered no injury from the privation which the larva had to undergo. [The cocoons of the puss-moth are to be found upon the trunks of trees, but they are so rough, and so greatly re- sembling the bark, with which, indeed, their walls are strengthened, that an inexperienced eye would fail to detect them. Even when they have been pointed out to a novice in practical entomology, he has failed to find them again when- ever his eye has been taken off their rugged outlines.] A question will here suggest itself to the curious in- Cap ricorn-Beeile. 215 quirer, how the moth, which is not, like the caterpillar, furnished with maudibles for gnawing, can lind its way through so hard a wall. To resolve this question, it is asserted by recent naturalists (see Kirby and Spence, vol. iii. p. 15) that the moth is furnished with a peculiar acid for dissolving itself a passage. We have a specimen of the case of a puss-moth, in which, notwithstanding its strength, one of the ichneumons had contrived to deposit its eggs. In the beginning of summer, when we expected the moth to appear, and felt anxious to observe the recorded effects of the acid, we were astonished to find a large orange cuckoo-fly make its escape ; while another, which attempted to follow, stuck by the way and died. On detaching the cell from the box, we foimd several others, which had not been able to get out, and had died in their cocoons. (J. K.) ;:--¥V Ichneumon (Cphion hiteum), figured from tbe one mentioned. Among the carjienter-grubs may be mentioned that of the purple capricorn-beetle (Callidiiun violacenm), of which the Rev. Mr. Kirby has given an interesting account in the fifth voliuue of the 'Linnfean Transactions.' This insect feeds principally on fir timber which has been felled some time without having had the bark stripped off; but it is often found on other wood. Though occasionally taken in this kingdom, it is supposed not to have been originally a native. The circumstance of this destructive little animal attacking only such timber as had not been stripped of its bark ought to be attended to by all persons who have any concern in this article ; for the bark is a temptation not only to this, but to various other insects ; and much of the injury done in timber might be prevented, if the trees were ail barked as soon as they were felled. The female is furnished, at the posterior extremity of her body, with a 216 Insect Architecture. flat retractile tube, wliicli slie inserts between the bark and the wood, to the depth of about a quarter of an inch, and there deposits a single egg. By stripping oif the bark, it is easy to trace the whole progress of the grub, from the spot where it is hatched, to that where it attains its full size. It first proceeds in a serpentine direction, filling the space which it leaves with its excrement, resembling saw- dust, and so stopping all ingress to enemies from without. When it has arrived at its utmost dimensions, it does not confine itself to one direction, but works in a kind of labyrinth, eating backwards and forwards, which "gives the wood under the bark a very irregular surface : by this means its paths are rendered of considerable wddth. The bed of its paths exhibits, when closely examined, a curious appearance, occasioned by the gnawings of its jaws, which excavate an infinity of little ramified canals. When the insect is about to assume its chrysalis state, it bores down obliquely into the soKd wood, to the depth sometimes of thi-ee inches, and seldom if ever less than two, forming holes nearly semi-cylindi'ical, and of exactly the form of the grub which inhabits them. At fii'st sight one would wonder how so small and seemingly so weak an animal could have strength to excavate so deep a mine ; but when we examine its jaws, our wonder ceases. These are large, thick, and solid sections of a cone divided longitudinally, which, in the act of chewing, apply to each other the whole of their interior plane surface, so that they grind the insect's food like a pair of millstones. Some of the grubs are hatched in October ; and it is supposed that about the beginning of March they assume their chrysalis state. At the place in the bark opposite to the hole from whence they descended into the wood, the j)erfect insects gnaw their way out, which generally takes place betwixt the middle of May and the middle of June. These insects are supposed onty to fly in the night, but during the daj' they may generally be found resting on the wood from which they were disclosed. The grubs are destitute of feet, pale, folded, somewhat hairy, convex above, and Oah-harh Caterj)iUars. 21' divided iuto tliirteen segments. Their head is lai-go and convex.* It would not bo easy to find a more striking example o' ingenuity than occurs in a small caterpillar which m hi; found in May, on the oak, and is supi)osed by Kir and Speuce to bo that of the Pi/ralis strigidalis. It is a whitish-yellow colom*, tinged with a shade of carnatio; and studded with tufts of red hairs on each segment, a; two brown spots behind the head. It has fourteen fe^ and the upper part of its body is much flatter than is common in caterpillars. When this ingenious little insect begins to form its cell, it selects a smooth young branch of the oak, near an oifgoing of the branchlets whose angle may afford it some protection. It then measures out, with its body for a rule, the space destined for its structure, the Magnified Cells of Pyralis strigulalis? a. The walls before they are joined, h. Walls Joined, but not closed at top. c. Side view of structure complete. basement of which is of a triangular form, with the apex at the lower end. The building itself is composed of small, rectangular, strap-shaped pieces of the outer bark of the branch cut out from the immediate vicinity ; the insect * Knby, m ' Lmn. Trans.,' vol. v. p. 246, aud Introd. ii. 218 Insect Architecture. indeed never travels further for materials than the length of its own body. Upon the two longest sides of the tri- angular base it builds uniform walls, also of a triangular shape, and both gradually diverging from each other as they increase in height. These are formed with so much mathematical precision, that they fit exactly when they are afterwards brought into contact. As soon as the littlo architect has completed these walls, which resemble very much the feathers of an arrow, it proceeds to draw them together in a manner similar to that which the leaf-rolling caterpillars employ in constructing their abodes, by pulling them with silken cords till they bend and converge. Even when the two longest sides are thus joined, there is an opening left at the upper end, which is united in a similar manner. When the whole is finished, it requires close inspection to distinguish it from the branch, being formed of the same materials, and having consequently the same colour and gloss. Concealment, indeed, may be supposed, with some justice, to be the final object of the insect in producing this appearance, the same principle being ex- tensively exemplified in numerous other instances. 219 CHAPTER XI. EARTH-MASON CATERPILLARS. ll/fANY species of caterpillars are not only skilful in con- -'-'-'- coaling themselves in their cocoons, but also in the concealment of the cocoon itself ; so that even when that is large, as in the instance of the death's-head hawk-moth (Achewntia atropos), it is almost impossible to find it. We allude to the numerous class of caterpillars which, previous to their changing into the pupa state, bury themselves in the earth. This cii-cumstance would not be surprising, were it confined to those which are but too well known in gardens, from their feeding upon and destroying the roots of lettuce, chicory, and other plants, as they pass a considerable por- tion of their lives under ground ; nor is it surprising that those which retire under ground during the day, and come abroad to feed in the night, should form their cocoons where they have been in the habit of concealing themselves. But it is very singular and iinexpected, that caterpillars which pass the whole of their life on plants and even on trees, should afterwards bury themselves in the earth. Yet, the fact is, that perhaps a greater number make their cocoons under than above ground, particularly those which are not clothed with hair. Some of those caterpillars which go into the ground previous to their change make no cocoon at all, but are contented with a rude masonry of earth as a nest for their pupaB : into the details of their operations it will not be so necessary for us to go, as into those whick exhibit more ingenuity and care. When one of the latter is dug up it has the appearance of nothing more than a small clod of earth, of a roundish or oblong shape, but, generally, by no means uniform. The interior, however, when it is laid 220 Insect Architecture. open, always exliibits a cavity, smootli, polisliecl, and regular, in which the cocoon or the chrysalis lies secure (Fig. b, p. 221). The polish of the interior is j^recisely such as might be given to soft earth by moistening and kneading it with great care. But beside this, it is usually lined with a tapestry of silk, more or less thick, though this cannot always be discovered without the aid of a magnifying glass. This species of caterpillars, as soon as they have completed their growth, go into the earth, scoop out, as the cossus does in wood, a hollow cell of an oblong form, and line it with pellets of earth, from the size of a grain of sand to that of a pea — united, by silk or gluten, into a fabric more or less compact, according to the species, but all of them fitted for protecting the inhabitant, during its winter sleep, against cold and moisture. Outside view of Nests of Earth-mason Caterpillars. One of the examples of this occurs in the ghost-motli (^Hepialus Jmmuli), which, before it retires into the earth, feeds upon the roots of the hop or the burdock. Like other insects which construct cells under ground, it lines the cemented earthen walls of its cell with a smooth tapestry of silk, as closely woven as the web of the house- spider. Inaccurate observers have inferred that these earthen structures were formed by a very rude and unskilful process — the caterpillar, according to them, doing nothing more than roll itself round, while the mould adhered to the gluey perspiration with which they describe its body to be covered. This is a process as far from the truth as Aristotle's account of the spider spinning, its web from wool taken from its body. Did the caterpillar do nothing more than roll itself Earth-Mason Cafeyjnllars. 221 in tlie earth, tlie cavity would be a long tube fitted exactly to its body (Fig. c) : it is essentially different. Xtits, ccc, of an Eaitb-nias.u Cucrpulai-. It does not indeed require very minute observation to perceive tbat every grain of earth in the structure is united to the contiguous grains by tln-eads of silk ; and that conse- quently, instead of the whole having been done at once, it must have required very considerable time and labour. This construction is rendered more obvious by throwing one of these earthen cases into water, which dissolves the earth, but does not act on the silk which binds it together. To understand how this is performed, it may not be uninterest- ing to follow the little mason from the beginning of his task. When one of those buiTowing caterpillars has done feed- ing, it enters the eartb to the depth of several inches, till it finds mould fit for its purpose. Having nowhere to throw the eai'th v.hich it may dig out, the only means in its power 222 Insect Architecture. of forming a cavity is to press it with its body ; and, by turning round and round for this purpose, an oblong hollow is soon made. But were it left in this state, as Reaumur v/ell remarks, though the vault might endure the requisite time by the viscosity of the earth alone, were no change to take i^lace in its humidity, yet, as a great number are wanted to hold out for six, eight, and ten months, they require to be substantially built ; a mere lining of silk, therefore, would not be sufficient, and it becomes necessary to have the walls bound Avith silk to some thickness. When a caterpillar cannot find earth sufficiently moist to bear kneading into the requisite consistence, it has the means of moistening it with a fluid which it ejects for the purpose ; and as soon as it has thus prej^ared a small jDellet of earth, it fits it into the wall of the vault, and secures it with silk. As the little mason, however, always works on the inside of the building, it does not, at first view, appear in what manner it can procure materials for making one or two additional walls on the inside of the one first built. As the process takes place under ground, it is not easy to discover the particulars, for the caterpillars will not work in glazed boxes. The difficulty was comjiletely overcome by M. Eeaumur, in the instance of the caterpillar of the water- betony moth {Cucidlia scrophularioe, Schrank), which ho permitted to construct the greater part of its under-ground building, and then dug it up and broke a portion oft" from the end, leaving about a third part of the whole to be re- built. Those who are unacquainted with the instinct of insects might have supposed that, being disturbed by the demolition of its walls, it would have left oft' work ; but the stimulus of providing for the great change is so powerful, that scarcely any disturbance will interrupt a caterpillar in this species of labour. The little builder accordingly was not long in recom- mencing its task for the purpose of repairing the disorder, which it accomjdished in about four hours. At first it pro- truded its body almost entirely beyond the breach which had been made, to reconnoitre the exterior for building materials. Earth-Mason Cater pilla rs. 223 Earth was put within its reach, of the same kind as it had jH'eviously used, and it was not long in selecting a grain adapted to' its purpose, which it fitted into the wall and secured with silk. It first enlarged the outside of the wall Earth-mason Caterpillars' Nests, with the perfect Moth, &c. by the larger and coarser grains, and then selected finer for the interior. But before it closed the aperture, it collected a quantity of earth on the inside, wove a pretty thick net- work tapestry of silk over the part which remained open, 224 Insect Architecture. and into tlie meshes of tliis, by pusliing and pressing, it thrust grains of earth, securing them with silk till the whole was rendered opaque ; and the further operations of the insect could no longer be watched, except that it was observed to keep in motion, finishing, no doubt, the silken taj)estry of the interior of its little chamber. When it was completed, M. Eeaumur ascertained that the portion of the structure which had been built under his eye was equally thick and compact with the other, which had been done under gi'ound. The grubs of several of the numerous species of may-fly {Ephemera) excavate burrows for themselves in soft earth, on the banks of rivers and canals, under the level of the water, an operation well described by Scopoli, Swammerdam, and Eeaumur. The excavations are always proportioned to the size of the inhabitant ; and consequently, when it is yoimg and small, the hole is proportionally small, though, with respect to extent, it is always at least double the length of its body. The hole, being under the level of the river, is always filled with v/ater, so that the grub swims in its native element, and while it is secure from being preyed upon by fishes, it has its own food within easy reach. It feeds, in fact, if we may judge from its egesta, upon the slime or moistened clay with which its hole is lined. In the bank of the stream at Lee, in Kent, we had occasion to take up an old willow stump, which, previous to its being driven into the bank, had been perforated in numerous places by the caterpillar of the goat-moth (Cossiis Ugni;perda). From having been driven amongst the moist clay, these perforations became filled with it, and the grubs of the ephemera) found them very suitable for their habitation : for the wood supplied a more secure protection than if their galleries had been excavated in the clay. In these holes of the wood we found several empty, and some in which were full-grown grubs. (J. E.) The architecture of the grub of a pretty genus of beetles, known to entomologists by the name of Cincmdela, is pecu- liarly interesting. It was first made known by the eminent Earth-Mason Caterpillars. 225 French naturalists, Geoffrey, Desmarest, and Latreille. Tliis grub, which may be met mth during spring, and also in summer and autumn, in sandy places, is long, cylindric, soft whitish, and furnished with six scaly brown feet. The Nest of the Grubs of Ephemerae A, The Gnib. B, Perforations in a river bank. C, One laid open to show the parallel structure. head is of a square form, with six or eight eyes, and very large in proportion to the body. They have strong jaws, and on the eighth joint of the body there are two fleshy tubercles, thickly clothed with reddish hairs, and armed Nests of Ephemerte in holes of Cossus. with a recurved horny spine, the whole giving to the grub the form of the letter Z. With their jaws and feet they dig into the earth to the depth of eighteen inches, forming a cylindrical cavity of Q 226 Insect Architecture. greater diameter than their body, and furnished with a perpendicular entrance. In constructing this, the grub first clears away the particles of earth and sand by placing them on its broad trapezoidal head, and carrying the load in this manner beyond the area of the excavation. When it gets deeper down, it climbs gradually up to the sm'face with similar loads by means of the tubercles on its back, above described. This process is a work of considerable time and difficulty, and in carrying its loads the insect has often to rest by the way to recover strength for a renewed exertion. Not unfrequently, it finds the soil so ill adapted to its operations, that it abandons the task altogether, and begins anew in another situation. When it has succeeded in forming a complete den, it fixes itself at the entrance by the hooks of its tubercles, which are admirably adapted for the purpose, forming a fulcrum or support, while the broad plate on the top of the head exactly fits the apertui'e of the excavation, and is on a level with the soil. In this position the grub remains immovable, with jaws expanded, and ready to seize and devour every insect which may wander within its reach, particularly the smaller beetles ; and its voracity is so great, that it does not spare even its own species. It precipitates its prey into the excavation, and in case of danger it retires to the bottom of its den, a cii-cumstance which renders it not a little difficult to discover the grub. The method adopted by the French natui*alists was to introduce a straw or pliant twig into the hole, while they dug away, by degrees and with great care, the earth around it, and usually found the grub at the bottom of the cell, resting in a zig-zag position like one of the caterpillars of the geometric moths. When it is about to undergo its transformation into a pupa, it carefully closes the mouth of the den, and retires to the bottom in security. . It does not appear that the grub of the genus Cincindela uses the excavation just described for the purpose of a ti*ap or pitfall, any further than that it can more effectually secure its prey by tumbling them down into it ; but there are other The Ant-Lion. 227 species of grubs which construct pitfalls for the express purpose of traps. Among these is the larva of a fly (Blicujio vermileo), not unlike the common flesh maggot. The den which it constructs is in the form of a funnel, the sides of which are composed of sand or loose earth. It forms this pitfall of considerable dejith, by throwing out the earth obliquely on all sides ; and when its trap is finished, it stretches itself along the bottom, remaining stift" and motion- less, like a piece of wood. The last segment of the body is bent at an angle with the rest, so as to form a strong point of support in the struggles which it must often have to encounter with vigorous prey. The instant that an insect tumbles into the pitfall, the grub pounces upon it, y\Tithes itself round it like a serpent, transfixes it with its jaws, and sucks its juices at its ease. Should the prey by any chance, escape, the grub hurls up jets of sand and earth, with astonishing rapidity and force, and not unfrequently suc- ceeds in again precipitating it to the bottom of its trap. The Ant-Lion. The observations of the continental naturalists have made known to us a pitfall constructed by an insect, the details of whose operations are exceedingly curious ; we refer to the grub of the ant-lion (Myrmeleon formicarius), which, though marked by Dr. Turton and Mr. Stewart as British, has not (at least of late years) been found in this country. As it is not, however, uncommon in France and Switzerland, it is jjro- bable it may yet be discovered in some spot hitherto unex- plored, and if so, it will well reward the search of the curious. The ant-lion grub being of a grey colour, and having its body composed of rings, is not unlike a wood-louse (Oniscus), though it is larger, more triangidar, has only six legs, and most formidable jaws, in form of a reaping-hook, or a pair of calliper compasses. These jaws, however, are not for masti- cating, but are perforated and tubular, for the purpose of sucking the juices of ants, upon which it feeds. Vallisnieri was therefore mistaken, as Reaumur well remarks, when he 228 Insect Architecture. supposed that lie liacl discovered its mouth. Its habits re- quire that it should walk backwards, and this is the only species of locomotion which it can perform. Even this sort of motion it executes very slowly ; and were it not for the ingenuity of its stratagems, it would fare but sparingly, since its chief food consists of ants, whose activity and swift- ness of foot would otherwise render it impossible for it to make a single capture. Nature, however, in this, as in nearly every other case, has given a compensating power to the individual animal, to balance its privations. The ant- lion is slow, but it is extremely sagacious ; it cannot follow its prey, but it can entrap it. The snare which the grub of the ant-lion employs consists of a funnel-shaped excavation formed in loose sand, at the "^^ ^ \ V W.^ Grub of the Ant-Lion, magnified, witlh me perfect Trap, and another begun. bottom of which it lies in wait for the ants that chance to stumble over the margin, and cannot, from the looseness of the walls, gain a sufficient footing to eftect their escape. By shutting up one of these grubs in a box with loose sand, it has been repeatedly observed constructing its trap The Ant-Lion. 229 of various dimensions, from one to nearly three inches in diameter, according to cii'cumstances. In the ' Magazine of Natural History,' 1838, p. 601, Mr. Westwood gives a very interesting account of the mode in which the ant-lion proceeds in the excavation of its pitfall, as witnessed by himself in specimens procured in the Pare de Belle Vue, near Paris, where, at the foot of a very high saud-bank, these pits were numerous, and of various sizes, but none exceeded an inch and a half or two inches in diameter, and two-thirds of an inch deep. " The ant-lions were of various sizes, corresponding to the size of their retreats. I brought many of them to Paris, placing several together in a box filled with sand. They, however, destroyed one another whilst shut up in these boxes ; and I only succeeded in bringing three of them alive to England, one of which almost immediately afterwards (on the 23rd of July) enclosed itself in a globular cocoon of fine sand. The other two afforded me many opportunities of observing their pro- ceedings. They were unable to walk forwards, — an anoma- lous circumstance, and not often met with in animals furnished with well-developed legs. It is generally back- wards, working in a spiral direction, that the creature moves, pushing itself backwards and downwards at the same time, the head being carried horizontally, and the back much arched, so that the extremity of the body is forced into the sand. In this manner it proceeds backwards (to use an Hibernianism), forming little mole-hills in the sand. But it does not appear to me that this retrograde motion has any- thing to do with the actual formation of the cell, since, as soon as it has fixed upon a spot for its retreat, it commences throwdng up the sand with the back of its head, jerking the sand either behind its back or on one or the other side. It shuts its long jaws, forming them into a kind of shovel, the sharp edges of which it thrusts laterally into the sand on each side of its head, and thereby contrives to lodge a quantity of the sand upon the head as well as the jaws. The motion is in fact something like that of the head of a goat, especially when butting sideways in play. In this manner 230 Insect Architecture. it contrives to tlirow away the sand, and by degrees to make a hole entirely with its head, the fore legs not affording the slightest assistance in the operation. During this perform- ance the head only is exposed, the insect having previously pushed itself beneath the surface of the sand ; but when it has made the hole sufficiently deep, it withdraws the head also, leaving only the jaws exposed, which are spread open in a line, and laid on the sand so as to be scarcely visible. If alarmed, the insect immediately takes a step backwards, •withdrawing the jaws ; but when an insect falls into the hole, the jaws are instinctively and instantaneously closed, and the insect seized by the leg, wing, or body, just as it may chance to fall within the reach of the ant-lion's jaws. If, however, the insect be not seized, but attempts to escape, no matter in what direction, the ant-lion immediately begins twisting its head about, and shovelling up the sand with the greatest agility, jerking it about on each side and backwards, but never forwards, as misrepresented in some figures, until the hole is made so much deeper, and such a distui-bance caused in the sides of the hole, that the insect is almost sure to be brought down to the bottom, when it is seized by the ant-lion, which immediately endeavours to draw it beneath the sand ; and if it be very boisterous, the ant-lion beats it about, holding it firmly by the jaws until it is too weak for further resistance. Hence, as the head of the ant-lion is immersed in the sand, it is evident that the accounts given in popular works of the instinct by which it throws the sand in the direction of the escaping prey are not quite correct. The act of throwing up the sand, when an insect has fallen into the pit and attempts to escape, has evidently for its chief object that of making the pit deeper and more conical, and therefore more difficult of ascent." It is by the action of the hinder pair of its legs that the ant-lion drags itself backwards, the other four pair being extended trailing after it, and leaving an impression on the surface of the fine sand over which it has passed ; and when burrowing its way beneath the surface of the sand, it proceeds by short steps backwards. A portion of sand at The Ant-Lion. 231 cacli step is thrown on tlio head, owing to tlic liiimp-likc form of the back : this is immediately jerked away, the body at the same time advancing another step in its backward and spiral motion. "Where it rests, a little hillock of sand is raised by the body of the ant-lion underneath ; while its jaws emerge and spread flat on the surface. It now probabfy commences its pitfall, the mode of excavating which we have given in detail. From the spiral course described by the ant-lion in its backward progress appears to have arisen the idea of its tracing out a circle as the outline of its pitfall — as would an architect or engineer ; but whence sprang the often-repeated statement, that the ant-lion loads its head with sand by means of one of its legs, that nearest the centre of the circle, we cannot conjecture. Nor do we know how, as it works entirely buried with the exception of the head, the ant-lion can act when it meets with a stone or other obstacle, as M. Bonnet states he has repeatedly witnessed. He observes that if the stone be small, it can manage to jerk it out in the same manner as the sand ; but when it is two or three times larger and heavier than its own body, it must Ant-Lion's Pitfalls, In an experimenting-bos. have recom"se to other means of removal. The larger stones it usually leaves till the last ; and when it has removed all the sand which it intends, it then proceeds to try what it can do with the less manageable obstacles. For this purpose it crawls backwards to the place where a stone may be, and thrusting its tail under it, is at great pains to get it properly balanced on its back, by an alternate motion of the rings composing its body. When it has succeeded in adjusting 232 Insect Architecture. the stone, it crawls up the side of the pit with great care, and deposits its burthen on the outside of the circle. Should the stone happen to be round, the balance can be kept only with the greatest difficulty, as it has to travel with its load upon a sloj)e of loose sand, which is ready to give way at dvery step ; and often when the insect has carried it to the very brink, it rolls off its back and tumbles down to the bottom of the pit. This accident, so far from discouraging the ant-lion, only stimulates it to more persevering efforts. Bonnet observed it renew these attempts to dislodge a stone five or six times. It is only when it finds it utterly im- possible to succeed, that it abandons the design and com- mences another pit in a fresh situation. When it succeeds in getting a stone beyond the line of its circle, it is not con- tented with letting it rest there ; but, to prevent it from again rolling in, it goes on to push it to a considerable distance. We may be pardoned for pausing before we give full credence to these details. The ant-lion feeds only on the blood or juice of insects ; and as soon as it has extracted these, it tosses the dry carcase out of its den. When it is about to change into a pupa, it proceeds in nearly the same manner as the caterpillar of the water-betony moth [Cucullia scroplmlarim). It first builds a case of sand, the particles of which are secured by threads of silk, and then tapestries the whole with a silken web. Within this it undergoes its transformation into a pupa, and in due time it emerges in form of a four -winged fly, closely resembling the dragon-flies {Lihelluloe), vulgarly and erroneously called horse-stingers. The instance of the ant-lion naturally leads us to consider the design of the Author of Nature in so nicely adjusting, in all animals, the means of destruction and of escape. As the larger quadrupeds of prey are provided with a most ingenious machinery for preying on the weaker, so are those furnished with the most admirable powers of evading their destroyers. In the economy of insects, we constantly observe that the means of defence, not only of the individual creatures, but of Tlie Ant-Lion. 233 their larvas and pupte, against tlic attacks of other insects, and of birds, is proportioned, in the ingenuity of their arrangements, to the weakness of the insect employing them. Those species which multiply the quickest have the greatest number of enemies. Bradley, an English naturalist, has calculated that two sparrows carry, in the coui'se of a week, above tkree thousand caterpillars to the young in their nests. But though this is, probably, much beyond the truth, it is certain that there is a great and constant destruction of individuals going forward; and yet the species is never destroyed. In this way a balance is kept up, by which one portion of animated nature cannot usurp the means of life and enjoyment which the world offers to another portion. In all matters relating to reproduction, Nature is prodigal in her arrangements. Insects have more stages to pass through before they attain their perfect growth than other creatures. The continuation of the species is, therefore, in many cases, provided for by a much larger number of eggs being deposited than ever become fertile. How many larvae are produced, in comparison with the number which pass into the pupa state ; and how many pupae perish before they become j)erfect insects ! Every garden is covered with caterpillars ; and yet how few moths and butterflies, comi^aratively, are seen, even in the most sunny season ? Insects which lay few eggs are, commonly, most remarkable in their contrivances for their preservation. The dangers to which insect life is exposed are manifold ; and therefore are the contrivances for its preservation of the most perfect kind, and invariably adapted to the peculiar habits of each tribe. The same wisdom determines the food of every species of insect ; and thus some are found to delight in the rose-tree, and some in the oak. Had it been otherwise, the balance of vegetable life would not have been preserved. It is for this reason that the contrivances which an insect employs for obtaining its food are curious, in proportion to the natural difficulties of its structure. The ant-lion is carnivorous, but he has not the quickness of the spider, nor can he sj^read a net over a large sm-face, and issue from his citadel to seize a victim 234 Insect Architecture. which he has caught in his out-works. He is therefore taught to dig a trap, where he sits like the unwieldy giants of fable, waiting for some feeble one to cross his path. How laborious and patient are his operations — how uncertain the chances of success! Yet he never shrinks from them, because his instinct tells him that by these contrivances alone can he preserve his own existence, and continue that of his species. 235 CEAPTEB XII. CLOTHES-MOTH AND OTHER TENT-MAKING CATEEPILLAES. — ■ LEAF AND BARK MINERS. npHERE arc at least five diifcrent species of moths similar -*- ill manners and economy, the caterpillars of which feed upon animal substances, such as furs, woollen cloths, silk, leather, and, what to the naturalist is no less vexing, upon the specimens of insects and other animals preserved in his cabinet. The moths in question are of the family named Tinea by entomologists, such as the tapestry-moth [Tinea tapctzella), the fur-moth {Tinea pellionella), the wool-moth (Tinea vestianella), the cabinet-moth (Tinea destructor, Stephens), &c. The moths themselves are, in the winged state, small and well fitted for making their way tlu'ough the most minute hole or chink, so that it is scarcely possible to exclude them by the closeness of a wardrobe or a cabinet.* If they cannot effect an entrance when a drawer is out, or a door open, they will contrive to glide through the key-hole ; and if they once get in, it is no easy matter to dislodge or destroy them, for they are exceedingly agile, and escape out of sight in a moment. Moufet is of opinion that the ancients possessed an effectual method of preserving stuffs from the moth, because the robes of Servius Tullius were preserved up to the death of Sejanus, a period of more than five hundred years. On turning to Pliny to learn this secret, we find him relating that stuff laid upon a cof&n will be ever after safe from moths; in the same way as a person once stung by a scorpion will never afterwards be stung by a bee, or a wasp, or a hornet ! Rhasis, again, says that cantharides suspended in a house drive away moths ; and he adds that * See Fig. (I, p. 238. 236 Insect Architedure. they will not touch anything wrapped in a lion's skin ! — the poor little insects, says Reaunuir, sarcastically, being probably in bodily fear of so terrible an animal.* Such are the stories which fill the imagination even of i^hilosophers, till real science entirely expels them. The efHuvium of camphor or turpentine, or fumigation by sulphur or chlorine, may sometimes kill them, when in the winged state, but this will have no effect upon their eggs, and seldom upon the caterpillars ; for they wrap themselves ujj too closely to be easily reached by any agent except heat. This, when it can be conveniently applied, will be certain either to dislodge or to kill them. When the effluvium of turpentine, however, reaches the caterpillar. Bonnet says it falls into convulsions, becomes covered with livid blotches, and dies.j The mother insect takes care to deposit her eggs on or near such substances as she instinctively foreknows will bo best adapted for the food of the young, taking care to dis- tribute them so that there vaaiy be a plentiful supply and enough of room for each. We have found, for example, some of those caterpillars feeding uj)on the shreds of cloth used in training wall-fruit trees ; but we never saw more than two caterpillars on one shred. This scattering of the eggs in many places renders the effects of the caterpillars more injurious, from their attacking many parts of a garment or a piece of stuff at the same time. (J. E.) When one of the caterpillars of this family issues from the egg, its first care is to provide itself with a domicile, which indeed seems no less indispensable to it than food ; for, like all caterpillars that feed under cover, it will not eat while it remains unprotected. Its mode of building is very similar to that which is employed by other caterpillars that make use of extraneous materials. The foundation or frame-work is made of silk secreted by itself, and into this it interweaves portions of the material upon which it feeds. It is said by Bingley, that "after having spun a fine coating of silk * Reaupiur, 'Mem. Hist. Insectes,' iii. 70. t ' Contemplation de la Nature,' puvt .\ii. chap. x. note. Moth- Caterpillars. 237 immediately around its body, it cuts the filaments of the wool or fur close by the thread of the cloth, or by the skin, with its teeth, which act in the manner of scissors, into convenient lengths, and aj^plies the bits, one by one, with great dexterity, to the outside of its silken case."* This statement, however, is erroneous, and inconsistent with the proceedings not only of the clothes-moth, but of every caterpillar that constructs a covering. None of these build from within outwards, but uniformly commence with the exterior wall, and finish by lining the interior with the finest materials. Eeaumur, however, found that the newly-hatched caterpillars lived at first in a case of silk. We have repeatedly witnessed the proceedings of these insects from the very foundation of their structures ; and, at the moment of writing this, we turned out one from the carcase of an " old lady moth" (Mormo maura, Ochsenheim) in our cabinet, and placed it on a desk covered with green cloth, where it might find materials for constructing another dwelling. It wandered about for half a day before it began its operations ; but it did not, as is asserted by Bonnet, and Kirby and Spence, " in moving from place to place, seem to be as much incommoded by the long hairs which surround it, us we are by walking amongst high grass," nor, " accordingly, marching scythe in hand," did it, " with its teeth, cut out a smooth road."| On the contrary, it did not cut a single hair till it selected one for the foundation of its intended structure. This it cut very near the cloth, in order, we suppose, to have it as long as possible ; and placed it on a line with its body. It then immediately cut another, and placing it parallel to the first, bound both together with a few threads of its own silk. The same process was repeated with other hairs, till the little creature had made a fabric of some thickness, and this it went on to extend till it was large enough to cover its body ; which (as is usual with caterpillar's) it employed as a model and measure for regiilat- * ' Animal Biography,' vol. iii. p. 330, Third Edition, t Bonnet, xi. p. 204 ; Kirby and Spence, ' Introduction,' i. 464, Fifth Edition. 238 Insect Architecture. ing its operations. We remarked that it made clioice of longer hairs for the outside than for the parts of the interior, which it thought necessary to strengthen by fresh additions ; but the chamber was ultimately finished by a fine and closely- woven tapestry of silk. We could see the progress of its work by looking into the opening at either of the ends ; for at this stage of the structure the walls are quite opaque, and the insect concealed. It may be thus observed to turn round, by doubling itself and bringing its head where the tail had just been ; of course, the interior is left wide enough for this purpose, and the centre, indeed, where it turns, is always wider than the extremities. (J. E.) "When the caterpillar increases in length, it takes care to add to the length of its house, by working in fresh hairs at Cases, &c., of tbe Clotbes-Moth (Tjiica j)e/Zto)!c?Za).— a, Ca(erpillai- ffeediiig in a case, which has been lengthened Ijy ovals of different colours ; 6, Case cut at the ends for experiment; c, Case cut open by the insect for enlarging it; d, e, The clothes-moths in their perfect state, when, as they cease to eat, they do no further injury. either end ; and if it be shifted to stuffs of different colours, it may be made to construct a party-coloured tissue, like a Scotch plaid. Eeaumur cut off with scissors a portion at each end, to compel the insect to make up the deficiency. But the caterpillar increases in thickness as well as in length, so that, its first house becoming too narrow, it must either enlarge it, or build a new one. It j^refers the former as less troublesome, and accomplishes its j^urpose "' as dexterously," dloih-CateiyiUars. 231) says Bonnet, " as any tailor, and sots to work precisely as we should do, slitting the case on the two opposite sides, and then adi'oitly inserting between them two pieces of the requisite size. It docs not, however, cut open the case from one end to the other at once ; the sides would sepai-atc too far asunder, and the insect be left naked. It therefore first cuts each side about half-way down, beginning sometimes at the centre and sometimes at the end (Fig. c), and then, after having filled up the fissm-e, proceeds to cut the remaining half; so that, in fact, foui- enlargements are made, and four separate pieces inserted. The coloiu' of the case is always the same as that of the stuft' from which it is taken. Thus, if its original colour be blue, and the insect, previously to enlai'ging it, be put upon red cloth, the circles at the end, and two stripes down the middle, will be red."* Reaumur found that they cut these enlargements in no precise order, but sometimes continuously, and sometimes opposite each other, indifferently. The same naturalist says he never knew one leave its old dwelling in order to build a new ; though, when once ejected by force from its house, it would never enter it again, as some other species of caterpillars will do, but always preferred building another. We, on the contrary, have more than once seen them leave an old habitation. The very caterpillar, indeed, whose history we have above given, first took up its abode in a sj)ecimen of the ghost-moth (Hepialiis humuli), where, finding few suitable materials for building, it had recoui'se to the cork of the drawer, with the chips of which it made a structure almost as warm as it would have done from wool, ^^'hether it took offence at oui* disturbing it one day, or whether it did not find sufficient food in the body of the ghost-moth, we know not ; but it left its cork house, and travelled about eighteen inches, selected "the old lady," one of the largest insects in the drawer, and built a new apartment, composed partly of cork as before, and partly of bits dipt out of the moth's wings. (J. E.) We have seen these caterpillars form their habitations ol * Bonnet, toI. is. p. 203. 240 Insect Architecture. every sort of insect, from a butterfly to a beetle ; and the soft, feathery wings of moths answer their purpose very well : but when they fall in with such hard materials as the musk beetle (Cerambyx moschatus), or the large scolo- pendra of the West Indies, they find some difficulty in the building. When the structure is finished, the insect deems itself seciu'e to feed on the materials of the cloth or other animal matter within its reach, provided it is di-y and free from fat i Transformations of the honeycomb-moths, a a, a. Galleries of the cell-boring cater- pillar ; 6, the female ; c, the male moth (^Galleria alvearia) ; d d d d, galleries of the wax-eating caterpillar, e.'seen at the entrance ; /, the same exposed ; g, its cocoon ; h, the moth (^Galleria cereana). or grease, which Eeaumur found it would not touch. This may probably be the origin of the practice of putting a bit of caudle with furs, &c., to preserve them from the moth. For building, it always selects the straightest and loosest pieces of wool, but for food it j^refers the shortest and most compact ; and to procure these it eats into the body of the stufi", rejecting the pile or nap, which it necessarily cuts across at the origin, and permits to fall, leaving it threadbare, as if it had been Tent-Maliing Caterpillars. 241 much worn. It must have been this circumstance whicli induced Bonnet to fancy (as we have already mentioned) that it cuts the hairs to make itself a smooth, comfortable path to walk upon. It would be equally correct to say that an ox or a sheep dislikes walking amongst long grass, and therefore eats it down in order to clear the way. [There is a little insect closely allied to these moths, which does a vast amount of harm to the bee-combs. This is the honey-comb moth, of which there are in England two species, both belonging to the genus Galleria. This little creatm'e is continually trying to make its way into the hives, and is as continually opposed by the bees, who instinctively know their enemy. If it once slips past the guards, the imfortunate bees are doomed to lose a considerable amount of their stored treasures, and have sometimes been so worried that they have been obliged to leave the hive altogether. [As soon as it can hide itself in an empty cell — an easy matter enough for so tiny a moth, which harmonizes exactly in colour with the bee-combs — it proceeds to lay its eggs, and, having discharged its office, dies. The eggs soon hatch into little grubs and caterpillars with very hard horny heads and soft bodies. As soon as they come into the dark world of the hive, they begin to eat their way through the combs, spinning the while a tunnel of silk, which entirely protects them from the stings of the bees. They can traverse these tunnels vdih. tolerable speed, so that the bees do not know where to find their enemies ; and if perchance they should discover one of them at the mouth of its burrow, the hard, horny head is all that is visible, and against its polished sm-faee the sting of tlie bee is useless. The rapidity with which they drive the silken tubes thi-ough the comb is really marvellous ; and even if they get among a collection of empty bee-combs, they make as much havoc as if they were bred in the hive from which the combs were taken. [In the accompanying illustration are seen figures of the two species of honey -moths, together with their tunnels. The species may be easily distinguished by the shape of the wings, Galleria alvearia having, as seen at Figs, h, c, the ends 242 Insect Architecture. of its wings rounded, and Galleria cereana having them squared. [Some moths, also belonging to the vast Family Tineidfe, do much damage to grain, and have also the habit of spinning silken tissues as they eat their way through the grain. One of them is more plentiful on the Continent than in England, but is known in this country by the name of the mottled Avoollen moth (Tinea granella)\ The caterpillar, which is smooth and white, ties together with silk several grains of wheat, barley, rye, or oats, weaving a gallery between them, from which it projects its head while feeding ; the grains, as Eeaumur remarks, being prevented from rolling or slipping by the silk which unites them. He justly ridicules the absurd notion of its filing off the outer skin of the wheat by rubbing upon it with its body, tho latter being the softer of the two , and he disproved, by experiment, Leeuwenhoeck's assertion that it will also feed on woollen cloth. It is from the end of May till the beginning of July that the moths, which are of a silvery grey, spotted with brown, appear and lay their eggs in gi'anaries. Transformations of the Grain-moths, a, Grain of barley, includinp; a caterpillar , b, c, the grain cut across, seen to be hollowed out, and divided by a partition of silk ; d, the moth (^Tinea Hcnrdei) ; e, grains of wh-at tied tosether by the caterpillar- /, g. the cater- pillar and moth (^Euplocamus grandla). The caterpillar of another still more singular grain-moth {Tinea Mordei, Kirbt and Spence) proves sometimes very Tent-Making Caterpillars. 243 destructive of grauaries. The mother-moth, in May or June, lays about twenty or more eggs on a grain of barley or wheat ; and when the caterpillars arc hatched they disjierse, each selecting a single grain. M. Eeaumur imagines that sanguinary wars must sometimes arise, in cases of pre- occupancy, a single grain of barley being a rich heritage for one of these tiny insects ; but he confesses he never saw such contests. When the caterpillar has eaten its way into the interior of the grain, it feeds on the farina, taking care not to gnaw the sldn nor even to throw out its excrements, so that except the little hole, scarcely discernible, the grain appears quite sound. When it has eaten all the farina, it spins itself a case of silk within the now hollow grain, and changes to a pupa in November. Tent-making Caterpillars. The caterpillai's of a family of small moths (Tineidte), which feed on the leaves of various trees, such* as the hawthorn, the elm, the oak, and most fruit-trees, particularly the pear, form habitations which are exceedingly ingenious and elegant. They are so very minute that they require close inspection to discover them ; and to the cui-sory observer, unacquainted with their habits, they will appear more like the withered leaf-scales of the tree, thi'own oif when the buds expand, than artificial structures made by insects. It is only, indeed, by seeing them move about upon the leaves, that we discover they are inhabited by a living tenant, who carries them as the snail does its shell. These tents are from a quarter of an inch to an inch in length, and usually about the breadth of an oat-straw. That they are of the colour of a withered leaf is not sm-prising ; for they are actually composed of a piece of leaf; not, how- ever, cut out from the whole thickness, but artfully separated fi'om the upper layer, as a person might separate one of the leaves of paper from a sheet of pasteboard. The tents of this class of caterpillars, which are found on the elm, the alder, and other trees with serrated leaves, are 244 Insect Architecture. much in the shape of a minute gohlfish. They are convex on the back, where the indentations of the leaf out of which they have been cut achl to the resemblance, by appearing like the dorsal fins of the fish. By depnving one of those cater- pillars common on the hawthorn of its tents, for the sake of experiment, we put it under the necessity of making another ; for, as Pliny remarks of the clothes-moth, they will rather die of hunger than feed unprotected. When we placed it on A CaterpiUar's tent upon a leaf of tlie elm. — a, a, The p.-.rt of tbc leaf from which the teut has been cut out; &, the tent itself. a fresh hawthorn leaf, it repeatedly examined every part of it, as if* seeking for its lost tent, though, when this was put in its way, it would not again enter it ; but, after some delay, commenced a new one. (J. E.) For this purpose, it began to eat through one of the two outer membranes which compose the leaf and enclose the pulp (parenchyma), some of which, also, it devoured, and then thrust the hinder part of its body into the perforation. The cavity, however, which it had formed, being yet too small for its reception, it immediately resumed the task of making it larger. By continuing to gnaw into the pulp hetioeen the membranes of the leaf (for it took the greatest care not to puncture or injure the membranes themselves), it soon succeeded in mining out a gallery rather larger than was sufficient to contain its body. We perceived that it did not throw out as rubbish the pulp it dug into, but devoured it as food — a circumstance not the least remarkable in its proceedings. As the two membranes of leaf thus deprived of the enclosed pulp appeared v/hite and transparent, every move- ment of the insect within could be distinctly seen ; and it Teni-MaTiing CateyyiUars. 245 was not a little iuteresting to watch its ingenious operations while it was making its tent from the membranes i^repared as we have just described. These, as lleaumur has re- marked, are in fact to the insect like a piece of cloth in the hands of a tailor ; and no tailor could cut out a shape with more neatness and dexterity than this little workman docs. As the caterpillar is furnished in its mandibles with an excellent pair of scissors, this may not appear to be a difli- cult task ; yet, when wc examine the matter more minutely, we find that the peculiar shape of the tn'o extremities re- quires different curvatures, and this, of course, renders the operation no less complex, as Eeaumur subjoins, than the shaping of the pieces of cloth for a coat.* The insect, in fact, shapes the membranes slightly convex on one side and concave on the other, and at one end twice as large as the other. In the instance which we obsei"ved, beginning at the larger end, it bent them gently on each side by pressing them with its body thrown into a curve. We have not said it cuts, but shapes its materials ; for it must be obvioiis that if the insect had cut both the membranes at this stage of its operations, the pieces would have fallen and carried it along with them. To obviate such an accident it proceeded to join the two edges, and seciu-e them fii-mly with silk, before it made a single incision to detach them. When it had in this manner joined the two edges along one of the sides, it inserted its head on the outside of the joining, fii'st at one end and then at the other, gnawing the fibres till that whole side was separated. It proceeded in the same manner with the other side, joining the edges before it cut them : and when it arrived at the last fibre, the only remaining support of its now finished tent, it took the precaution, before snipping it, to moor the whole to the uncut part of the leaf by a cable of its o\\m silk. Consequently, when it does cut the last nervure, it is secure from falling, and can then travel along the leaf, carrying its tent on its back, as a snail does its shell. (J. E.) * ' ^lem. Iliot. lusect.' iii. p. 106. 246 Insect Architecture. We have just discovered (Nov. 4tli, 1829) upon the nettle a tent of a very singular appearance, in consequence of the materials of which it is made. The caterpillar seems, indeed, to have proceeded exactly in the same mauner as those which we have described, mining first % a, The Caterpillar occupying the space it has eaten between the cuticU s of the leaf ; 6, a portion of the upper cuticle, cut. out for the formation of the tent; c, the tent nearly completed ; d, the perfect tent, with the caterpillar protruding its head. between the two membranes of the leaf, and then uniting these and cutting out his tent. But the tent itself looks singidar from being all over studded with the stinging bristles of the nettle, and forming a no less formidable coat of mail to the little inhabitant than the spiny hide of the hedgeliog. In feeding it does not seem to have mined into the leaf, but to have eaten the whole of the lower membrane, along with the entire pulp, leaving nothing but the upper membrane untouched. (J. E.) During the smnmer of 1830 we discovered a very large tent which had been formed out of a blade of grass ; and another stuck all over with chips of leaves upon the common maple. Tents of Stone-Mason CATERriLLARs. The caterpillar of a small moth {Tinea') which feeds upon the lichens growing on walls, builds for itself a moveable tent of a very singular kind. M. de la Voye was the first who described these insects ; but though they are frequently overlooked, from being very small, they are by no means Stone-Mason fJaterj>iUars. 247 uncommon on old walls. Eeaumur observed them regularly for twenty years together on the terrace- wall of the Tuilcrics at Paris ; and they may bo found in abimdance in similar situations in this coimtry. This accuivate observer refuted by experiment the notion of M. de la Voye that the cater- pillars fed upon the stones of the wall ; but he satisfied himself that they detached particles of the stone for the purpose of building their tents or sheaths (fourreaux), as he calls their dwellings. In order to watch their mode of building, Eeaumur gently ejected half-a-dozen of them from their homes, and observed them detach grain after grain from a piece of stone, binding each into the wall of their Lichen-Tents and Caterpillars, both of their natural size and magnified. building with silk till the cell acquired the requisite magni- tude, the whole operation taking about twenty-four hom-s of continued labour. M. de la Voye mentions small granular bodies of a greenish colour, placed irregularly on the ex- terior of the structure, w^hich he calls eggs ; but we agree with Eeaumur in thinking it more probable that they are small fragments of moss or lichen intermixed with the stone : in fact, we have ascertained that they are so. (J. E.) When these little architects prepare for theii' change into chrysalides before becoming moths, they attach their tents securely to the stone over which they have hitherto rambled, by spinning a strong mooring of silk, so as not only to fill up every interstice between the main entrance of the tent and the stone, but also weaving a close, thick 248 Insect Architecture. curtain of the same material, to shut up the entire aper- ture. It is usual for insects which form similar structures to issue, when they assume the winged state, from the broader end of their habitation ; but our little stone-mason proceeds in a different manner. It leaves open the apex of the cone from the fii-st, for the purpose of ejecting its excrements, and latterly it enlarges this opening a little, to allow of a free exit when it acquires wings ; taking care, however, to spin over it a canopy of silk, as a temporary protection, which it can afterwards burst through without difficulty. The moth itself is very much like the common clothes-moth in form, but is of a gilded-bronze colour, and considerably smaller. In the same locality, M. de Maupertuis found a nume- rous brood of small caterpillars, which employed grains of stone, not, like the preceding, for building feeding-tents, but for their cocoons. This caterpillar was of a brownish- grey colour, with a white line along the back, on each side of which were tufts of haii-. The cocoons which it built were oval, and less in size than a hazel-nut, the grains of the stone being skilfully woven into irregular meshes of silk. In June, 1829, we found a numerous encampment of the tent-building caterpillars described by MM. de la Voye and Eeaumiu', on the brick wall of a garden at Blackheath, Kent. (J. R.) They were so very small, however, and so like the lichen on the wall, that had not oiu' attention been previously directed to theii- habits, we should have considered them as portions of the wall ; for not one of them was in motion, and it was only by the neat, turbi- nated, conical form in which they had constructed their habitations that we detected them. We tried the experi- ment above mentioned, of ejecting one of the caterpillars from its tent, in order to watch its proceedings when con- structing another ; but probably its haste to procure shelter, or the artificial circumstances into which it was thrown, influenced its operations, for it did not form so good a tent Stone-Mason Caterpillars. 249 as the fii'st, the texture of the walls being much slighter, while it was more roimJed at the apex, and of course not so elegant. Reaumiu* found, in all his similar experiments, that the new structure equalled the old ; but must of the trials of this kind which we have made correspond with the inferiority which we have here recorded. The process indeed is the same, but it seems to be done with more hui-ry and less care. It may be, indeed, in some cases, that the supply of silk necessary to unite the bits of stone, earth, or lichen employed, is too scanty for perfecting a second structure. We remarked a very singular cii'cumstance in the opera- tions of our little architect, which seems to have escaped the minute and accurate attention of Eeaumui'. When it commenced its structui-e, it was indispensable to lay a foun- dation for the walls about to be reared ; but as the tent was to be moveable like the shell of a snail, and not stationary, it would not have answered its end to cement the foundation to the wall. We had foreseen this difficulty, and felt not a little interested in discovering how it Avould be got over. Accordingly, upon watching its movements with some atten- tion, we were soon gratified to perceive that it used its own body as the primary support of the building. It fixed a thread of silk upon one of its right feet, warped it over to the corresponding left foot, and upon the thread thus stretched between the two feet it glued grains of stone and chips of lichen, till the wall was of the required thickness. Upon this, as a foundation, it continued to work till it had formed a small portion in form of a parallelogram ; and proceeding in a similar way, it was not long in making a ring a very little wider than sufficient to admit its body. It extended this ring in breadth, by working on the inside only, narrowing the diameter by degrees, till it began to take the form of a cone. The apex of this cone was not closed up, but left as an aperture thi'ough which to eject its excrements. It is worthy of remark, that one of the caterpillars which we deprived of its tent attempted to save itself the* trouble 250 Insect Architecture. of building a new one, by endeavouring to unliouse one of its neigliboiu'S. For this purpose, it got upon tbe outside of tlie inhabited tent, and, sliding its head down to the entrance, tried to make its way into the interior. But the rightful owner did not choose to give up his premises so easily, and fixed his tent down so firmly upon the table where we had placed it, that the intruder was forced to abandon his attempt. The instant, however, that the other unmoored his tent and began to move about, the invader renewed his efforts to eject him, persevering in the struggle for several houj'S, but without a chance of success. At one time we imagined that he would have accomplished his felonious intentions ; for he bound down the apex of the tent to the table with cables of silk. But he attempted his entrance at the wrong end. He ought to have tried the aperture in the apex, by enlarging which a little he would undoubtedly have made good his entrance ; and as the inhabitant could not have turned upon him for want of room, the castle must have been surrendered. This experiment, however, was not tried, and there was no hope for him at the main entrance. Muff-shaped Tents. The ingenuity of man has pressed into his service not only the wool, the hair, and even the skins of animals, but has most extensively searched the vegetable kingdom for the materials of his clothing. In all this, however, he is rivalled by the tiny inhabitants of the insect world, as we have already seen ; and we are about now to give an addi- tional instance of the art of a species of caterpillars which select a warmer material for their tents than even the eater- pillar of the clothes-moth. It may have been remarked by many who are not botanists, that the seed-catkins of the willow become, as they ripen, covered with a species of down or cotton, which, however, is too short in the fibre to be advantageously emi)loyed in our manufactures. But the caterpillars, to which we have alluded, find it well adapted for their habitations. Mining Caterpillars. 251 The muff-looking tent in which wo find these insects does not require much trouble to construct ; for the caterpillar does not, like the clothes-moth caterpillar, join the ■willow- cotton together, fibre by fibre — it is contented with the a. Branch of tbe Willow, with seed-spikes covered with cotton ; h. Muff-tents, made of this cotton by c, the Caterpillar. state in which it finds it on the seed. Into this it burrows, lines the interior with a tapestry of silk, and then detaches the whole from the branch where it was growing, and carries it about with it as a protection while it is feeding.* An inquiring friend of Eeaumur having found one of these insects floating about in its muff-tent upon water, concluded that they feed upon aquatic plants ; but he was soon convinced that it had only been blown down by an accident, which must frequently happen, as willows so often hang over water. May it not be, that the buoyant materials of the tent were intended to furnish the little inhabitant * Reuumiir, iii. p. 130. 252 Insect ArcMteciure. with a life-boat, in whicli, when it chanced to be blown into the water, it might sail safely ashore and regain its native tree? Leaf-mining Catekpillars. The process of mining between the two membranes of a leaf is carried on to a farther extent by minute caterpillars allied to the tent-makers above described. The tent-maker never deserts his house, except when comiielled, and there- fore can only mine to about half the length of his own body ; but the miners now to be considered make the mine itself their dwelling-place, and as they eat their way, they lengthen and enlarge their galleries. A few of these mining caterpillars are the progeny of small weevils (Curculionklce), some of two-winged flies (Diptera), but the greater number are produced from a genus of minute moth (CEcophora, Late.), which, when magnified, appear to be amongst the most splendid and brilliant of Nature's productions, vying even with the humming-birds and diamond-beetles of the tropics in the rich metallic colours which bespangle their wings. Well may Bonnet call them " tiny miracles of Nature," and regret that they are not en grand* There are few plants or trees whose leaves may not, at some season of the year, be found mined by these cater- pillars, the track of whose progress appears on the upper surface in winding lines. Let us take one of the most common of these for an example, — that of the rose-leaf, produced by the caterpillar of Eay's golden-silver spot (Argyromiges Bayella ? Cuetis), of which we have just gathered above a dozen specimens from one rose-tree. (J.E.) It may be remarked that the winding line is black, closely resembling the tortuous course of a river on a maj), — begin- ning like a small brook, and gradually increasing in breadth as it proceeds. This representation of a river exhibits, be- sides, a narrow white valley on each side of it, increasing as it goes, till it terminates in a broad delta. The valley is the * Bonnet, ' Contempl. de la Nature,' part xii. Mill ing CatoyiUars. 253 portion of tLe iuner leaf from •which the caterpillar has eaten the jnilp (jiarenchyma), while the river itself has hcen formed by the liquid ejecfamenta of the insect, the watery- part becoming evaporated. In other species of miners, Leaf oflbe ^lonthly Rose (Rose Indica), mined bj' Caterpillars of Argyrainiges? however, the dung is hard and dry, and consequently these only exhibit the valley without the river ^see p. 255). On looking at the back of the leaf, where the winding line begins, we uniformly find the shell of the very minute egg from which the caterpillar has been hatched, and hence perceive that it digs into the leaf the moment it escapes from the egg, without wandering a hair's-breadth from the spot ; as if afraid lest the air should visit it too roughly. The egg is, for the most part, placed upon the mid-rib of the rose-leaf, but sometimes on one of the larger nervures. When once it has got within the leaf, it seems to pursue no certain direc- tion, sometimes working to the centre, sometimes to the circumference, sometimes to the point, and sometimes to the base, and even, occasionally, crossing or keeping parallel to its own previous track. The most marvellous circumstance, however, is the minuteness of its workmanship; for though a rose-leaf is thinner than this paper, the insect finds room to mine a tunnel to live in, and plenty of food, without toucliing 254 Insect Architecture. tlie two external membranes. Let any one try with the nicest dissecting instrimients to separate the two plates of a rose-leaf, and he will find it impossible to proceed far without tearing one or other. The caterpillar goes still further in minute nicety; for it may be remarked, that its track can only be seen on the upper, and not on the under surface of the leaf, proving that it eats as it pro- ceeds only haK the thickness of the jiulp, or that portion of it which belongs to the upper membrane of the leaf. We have found this little miner on almost every sort of rose-tree, both wild and cultivated, including the sweet-briar, in which, the leaf being very small, it requires nearly the whole parenchyma to feed one caterpillar. They seem, how- ever, to prefer the foreign monthly rose to any of our native species, and there are few trees of this where they may not be discovered. Leaf of the Dew-berry B.amble (liub.is ccBdus), mined by Cutcrjjillars. Tunnels very analogous to the preceding may be found uj)on the common bramble (Bubus fruticosus) ; and on the holly, early in spring, one which is in form of an irregular whitish blotch. But in the former case, the little miner seems to proceed more regularly, always, when newly hatched, making directly for the circumference, upon or near which also the mother -moth deposits her egg, and winding along for half the extent of the leaf close upon the edge, following, in some cases, the very indentations formed by the terminating nervures. Mining CaterpiUars. 255 The bramble-leaf miner seems also to cliftcr from that of the rose-leaf, by eating the pulp both from the upper and uuder surface, at least the track is equally distinct above and below ; yet this may arise from the different consistence of the leaf pulp, that in the rose being firm, while that of the bramble is soft and puffy. On the leaves of the common primrose {Primula veris), as well as on the garden variety of it, the polyanthus, one of those mining caterpillars may very frequently be found. It is, however, considerably different from the preceding, for there is no black trace — no river to the valley which it excavates : its ejectamenta, being small and solid, are seen, Leaf of the Priirirose (Primula veris), mined by a Caterpillar, when the leaf is di*ied, in little black points like grains of sand. This miner also seems more partial than the pre- ceding to the mid-rib and its vicinity, in consequence of which its path is seldom so tortuous, and often appears at its extremity to terminate in an area comparatively extensive, arising from its recrossing its previous tracks. (J. R.) Swammerdam describes a mining caterpillar which he found on the leaves of the alder, though it did not, like those we have just described, excavate a winding gallery ; it kept upon the same spot, and formed only an irregular area. A moth was produced from this, whose upper wings, he says, *' shone and glittered most gloriously with crescents of gold, silver, and brown, surrounded by borders of delicate black." Another area miner which he found on the leaves of willows, as many as seventeen on ono leaf, producing what appeared to be rusty spots, was meta- 256 Insect Architecture. morpliosed into a very miuute weevil {Curculio BMonoc). He say3 lie Las been informed that, in warm climates, worms an inch long are found in leaves, and adds, with great simplicity, " on these many fine experiments might have been made, if the inhabitants had not labom*ed under the cursed thirst of gold."* The vine-leaf miner, when about to construct its cocoon, cuts, from the termination of its gallery, two pieces of the membrane of the leaf, deprived of their pulp, in a similar manner to the tent-makers described above, uniting them and lining them with silk. This she carries to some distance before she lays herself up to undergo her change. Her mode of walking under her burthen is peculiar, for, not con- tented with the security of a single thread of silk, she forms, as Bonnet says, " little mountains (inonticules) of silk, from distance to distance, and seizing one of these with her teeth, drags herself forward, and makes it a scaffolding from which she can build another."! Some of the miners, however, do not leave their galleries, but undergo their transfomia- tions there, taking the precaution to mine a cell, not m the upper, but in the under surface ; others only shift to another portion of the leaf. Social Leaf-Mineks. The preceding descriptions apply to caterpillars who construct their mines in solitude, there being seldom more than one on a leaf or leaflet, unless when two mother-flies happen to lay their eggs on the same leaf ; but there are others, such as the miners of the leaves of the henbane (Hyos- cyamus niger), which excavate a common area in concert — from four to eight forming a colony. These are very like flesh-maggots, being larger than the common miners ; the leaves of this plant, from being thick and juicy, giving them space to work and plenty to eat. Most of the solitary leaf-miners either cannot or will not construct a new mine, if ejected by an experimenter from the old, as wo have frequently proved ; but this is not the * Swammerd., ' Book of Nature,' vol. ii. p. 84. f ' Contempl. Je la Nature,' part xii. p. 197. Barh-Mining Caterpillars. 257 case with the social miners of the henbane-leaf. Bonnet ejected one of these, and watched it with his glass till it commenced a new tminel, which it also enlai'ged with great expedition ; and in order to verify the assertion of Reaumui", that they neither endeavour nor fear to meet one another, he introduced a second. Neither of them mani- fested any knowledge of the other's contiguity, but both worked hard at the gallery, as did a third and a fourth which he afterwards introduced; for though they seemed uneasy, they never attacked one another, as the solitary ones often do when they meet.* Bark-mining Catebpillabs. A very different order of mining caterpillars are the progeny of various beetles, which excavate their galleries in the soft inner bark of trees, or between it and the young wood (alburnum). Some of these, though small, commit extensive ravages, as may readily be conceived when we are told that as many as eighty thousand are occasionally found on one tree. In 1783 the trees thus destroyed by the printer- beetle (Tomicus typographus. Late.), so called from its tracks resembling letters, amounted to above a million and a half in the Hartz forest. It appears there periodically, and confines its ravages to the fir. This insect is said to have been found in the neighbourhood of London. On taking off the bark of decaying poplars and willows, we have frequently met with the tracks of a miner of this order, extending in tortuous pathways, about a quarter of an inch broad, for several feet and even yards in length. The exca- vation is not circular, but a compressed oval, and crammed throughout with a dark-colom'ed substance like sawdust — the excrement no doubt of the little miner, who is thereby protected from the attacks of Staphjlinidce, and other pre- daceous insects from behind. But though we have found a great number of these subcortical tracks, we have never discovered one of the miners, though they are very probably * Bonnet, ' Observ. sur les Insectes,' vol. ii. p. 425. S 258 Insect Architecture. the grubs of the pretty musk-beetle (Ceramhyx moschatus), which are so abundant in the neighbourhood of the trees in question, that the very air in summer is perfumed with their odour. (J. E.) [Mr. Eennie is undoubtedly right in his suggestion. I have found similar holes in old willow trees, and have traced them throughout their varied ramifications. They contain the larvffi and pupae of the musk-beetle, some of which may be seen in the Museum at Oxford. On these trees, which mostly grow along the banks of the Chcrwell, the perfect beetle was so abundant that it might be taken in any number, and, as described by Mr. Eennie, the air was perfumed with its jiower- ful and agreeable odour. So strong is the scent of this beetle, that I have known it adhere to gloves after the lapse of many weeks, and I have often caught the scent when pass- ing along the road, and merely by the aid of the nostrils discovered the insect. [On account of the vast number of carpenter-beetles, it is impossible to notice more than a few of them, and we will therefore select some of the most conspicuous. One of them, belonging to the genus Ptilinus, is very familiar to us as bor- ing into wooden furniture, and producing the effect which is popularly called " worm-eaten." Fortunately, the little crea- tures can be easily ejected, and the wood rendered free of them ever afterwards. All that is needed is to take a syringe with a very fine aperture — an injecting syringe is the best — and by its aid to force into the holes a solution of corrosive sublimate in spirits of wine — say a large teaspoonful of the powdered salt to a pint of spirits. The rapidity with which the poisoned spirit permeates the wood is wonderful, and in a short time it may be seen oozing out of twenty or thirty holes at once. This solution is peculiarly effective, as it kills all the insects, de- stroys every egg that it touches, and renders the wood poison- ous to the gi'ubs that happen to escape. I used to be greatly plagued with the Ptilinus among my ethnological collection, until I tried the corrosive sublimate, and ever since my spears, bows and arrows, and clubs have remained intact. [Another troublesome insect is the Scohjtus destructor, Grubs of Beetles. 259 which makes its radiating tunnels between the bark and the tree. Whole forests have been destroyed by this voracious little beetle, the bark having been completely detached, and the tree necessarily killed. The habits of this beetle are well described in the following passage.] We have frequently observed a very remarkable instinct in the grubs of a species of beetle (Scolytus destructor, ^X^*\n!v -.%-***" Bark mined in rays by beelle-grubs. Geoffeot), which lives under the dead bark of trees. The mother insect, as is usual with beetles, deposits her eggs in a patch or cluster in a chink or hole in the bark ; and when the brood is hatched, they begin feeding on the bark which had formed their cradle. There is, of course, nothing wonderful in their eating the food selected by their mother ; but it appears that, like the caterpillars of the clothes- moth, and the tent insects, they cannot feed except under 260 Insect Architecture. cover. They dig, therefore, long tubular galleries between the bark and the wood ; and, in order not to interfere with the runs of their brethren, they branch off from the place of hatching like rays from the centre of a circle : though these are not always in a right line, yet, however near they may approach to the contiguous ones, none of them ever break into each other's premises. We cannot but admire the remarkable instinct implanted in these grubs by their Creator; which guides them thus in lines diverging farther and farther as they increase in size, so that they are pre- vented from interfering with the comforts of one another. [We now come to one or two of the beetles which bore deeply into the very wood of the trees. As a rule, the musk-beetle keeps rather towards the exterior of the tree, but there are many that are not so cautious, and which besides damage the tree additionally by nibbling a quantity of chips, wherewith they strengthen their cocoons. We will first take the two insects which are shown in the accompany- ing illustration. That on the right hand is a species of weevil, or Curculio, and is an undeseribed species belonging to the genus Khyncophorus. It is a native of Australia. The insect and its cocoon are drawn one thii-d less than their real size. The colour of the beetle is warm chestnut brown, and the bold marks on the thorax are jet black. In its larval state it burrows into the palm-trees, and when about to assume the pupal condition it makes the remarkable cocoon which is figured. Generally, these wooden cocoons are made of little chijjs which are bitten from the wood, and woven together with silk. This cocoon, however, is made of long fibres, which are torn rather than bitten, and are so long that one of them will sometimes encircle the cell three times, making an average length of nine inches. It is tolerably compact in structure, and the colour is pale brown. [On the left hand is an opened cocoon of an English beetle belonging to the genus Rhagium. Like the last-mentioned insect, the Rhagium prefers long fibres to short chips, though it does not use them of such a length as the Rhyn- cophorus. The cocoon is generally made between the bark Wasp-Beetle. 261 and the wood, from the latter of which the fibres are toru. lii consequeuce of the mode of structui'c, the cocoon is pale straw colour, while the hollow in which it rests is quite dark. [All entomologists ai'e familiar with the pretty little wasp- beetle (Ch/tus arietis), which derives its popular name from the wasp-like colours of its body. In the larval state it is one of the carpenter-grubs, and may bo found in posts, fir- trees, and similar localities. In this country, although Cocoon of Rhagium. Rhyncophonis and cocoon. plentiful, it is not numerous enough to do much harm ; but in Ceylon, a closely-allied species is one of the pests of the island. It is popularly known by the title of coffee- borer, from its habit of boring into the stems of the coffee- plant. The landowner looks with absolute horror on this pretty out destructive insect, and would pay a heavy sum annually to any one who would undertake to extirpate the tiny foe. Whole plantations have been swept off* by it, and 262 Insect Archiieciure. up to the present time no remedy lias had more than a temporary and partial success.] Another Capricorn beetle of this family is no less destructive to bark in its perfect state than the above are when grubs, as from its habit of eating round a tree, it cuts the course of the returning sap, and destroys it. [The late Mr. Waterton once showed me a stout branch which had fallen on his head while he was standing under a tree, the branch having been cut completely through by the jaws of some large longicorn beetle. The mode in which the insect had severed the branch was exactly like that which is practised by the beaver when it cuts down a tree. Capricorn Beetle (C'erambyx Lamia ampiUator) rounding off the bark of a tree. [The burrows and cocoons of two other species of Cerambyx are shown in the accompanying illustration, and in both cases may be seen the provision which is made for the exit of the beetle after it has attained the perfect condition. The double burrow of the left is that of Ceramhyx carcharias, and those on the right-hand figure aro the habitations of Ceramhyx populneus. The reader will see how these insects cut up the wood of the branch, and can well understand the infinite mischief which can be done to a cofiee plantation by the Clytus. The last wood-boring beetle which will be mentioned is Stag-Bmtle. 2G3 the stag-beetle of our own country. In the larval state this insect resides in tree trunks, mostly towards the roots, and therefore escapes observation more successfully than would be the case if it inhabited a higher portion of the tree. When full-grown, the larva is of enormous size, and the hole which it bores is necessarily of corresponding dimensions. In Cerambyx carcharias. Ceramhyx pnpulneus some parts of England, the larva are popularly called " Joe Bassetts," and are said to turn into " Pincher Bobs." The latter title is a very appropriate one, as any one can testify who has allowed a fine male stag-beetle to grip his finger between its jaws. As to the Joe Bassett, it is simply a local name.] 264 Insect Architectmre. CHAPTEE XIII. STRUCTURES OF GRASSHOPPERS, CRICKETS, AND BEETLES. GEASSHOPPERS, locusts, crickets, and beetles are, in many respects, no less interesting than the insects whose architectural proceedings we have already detailed. They do not, indeed, build any edifice for the accommodation of themselves or their progeny ; but most, if not all of them, excavate retreats in walls or in the ground. The house-cricket (Acheta domestica) is well known for its habit of picking out the mortar of ovens and kitchen fire- places, where it not only enjoys warmth, but can procure abundance of food. It is usually supposed that it feeds on bread. M. Latreille says it only eats insects, and it certainly thrives well in houses infested by the cockroach ; but we have also known it eat and destroy lamb's-wool stockings, and other wollen stuffs, hung near a fire to dry. It is evidently not fond of hard labour, but prefers those places where the mortar is already loosened, or at least is new, soft, and easily scooped out ; and in this way it will dig covert ways from room to room. In summer, crickets often make excursions from the house to the neighbouring fields, and dwell in the crevices of rubbish, or the cracks made in the ground by dry weather, where they chirp as merrily as in the snuggest chimney-corner. Whether they ever dig retreats in such circumstances we have not ascertained : though it is not improbable they may do so for the purpose of making nests. M. Bory St. Vincent tells us that the Spaniards are so fond of crickets that they keep them in cages like singing birds.* * Diet. Classique d'Hist. Nat. Art. Grillon. Mole-Cricket 265 The Mole-Cricket. The insect, called, from its similarity of habits to the mole, the mole-cricket (Gri/Uotcdj^a vuhjaris, Latr.), is but too well known in gardens, corn-fields, and the moist banks of rivers and ponds, in some parts of England, such as Wilt- shire and Hampshire, though it is comparatively rare or unknown in others. It burrows in the ground, and forms extensive galleries similar to those of the mole, though The llole-Cricket, with a srparate outline of one of its hands. smaller ; and these may always be recognized by a slightly elevated ridge of mould : for the insect does not throw up the earth in hillocks like the mole, but gradually, as it digs along, in the manner of the field-mouse. In this way it commits great ravages, in hotbeds and in gardens, upon peas, yoxmg cabbages, and other vegetables, the roots of which it IS said to devour. It is not improbable, we think, that, like its congener, the house-cricket, it may also prey upon under- ground insects, and undermine the plants to get at them, as the mole has been proved to do. Mr Gould, indeed, fed a mole-cricket for several months upon ants. The structure of the mole-cricket's arms and hands (if we 266 Insect Architecture. may call them so) is admirably adapted for these operations, being both very strong, and moved by a peculiar apparatus of muscles. The breast is formed of a thick, hard, horny substance, which is further strengthened within by a double framework of strong gristle, in front of the extremities of v/hich the shoulder-blades of the arms are firmly jointed : a structure evidently intended to j)revent the breast from being injured by the powerful action of the muscles of the arms in digging. The arms themselves are strong and broad, and the hand is furnished with four large sharp claws, pointed somewhat obliquely outwards, this being the direction in which it digs, throwing the earth on each side of its course. So strongly indeed does it throw out its arms, that we find it can thus easily support its own weight when Nest of the Mole-Cricket. held between tlie finger and thumb, as we have tried upon half-a-dozen of the living insects now in our possession. The nest which the female constructs for her eggs, in the beginning of May, is well worthy of attention. The Eev. Mr. White, of Selborne, tells us that a gardener, at a house where he was on a visit, while mowing grass by the side of a canal, chanced to strike his scythe too deep, and pared off a large piece of turf, laying open to view an interesting scene of domestic economy. There was a pretty chamber dug in the clay, of the form and about the dimensions it would have had if moulded by an egg, the walls being neatly smoothed and polished. In this little cell were deposited about a hundred eggs, of the size and form of caraway comfits, and of a dull tarnished white colour. The eggs were not very Field-Cricket 267 deep, but just under a little heap of frcsli mould, and witliin the influence of the sun's heat,* The dull tarnished white colour, however, scarcely agrees with a parcel of these eggs now before us, which are translucent, gelatinous, and greenish. Like the eggs and young of other insects, however, those of the mole-cricket are exposed to depredation, and par- ticularly to the ravages of a black beetle which bui-rows in similar localities. The mother insect, accordingly, does not think her nest secure till she has defended it, like a fortified town, with labyrinths, iutrenchments, ramparts, and covert ways. In some part of these outworks she stations herself as an advanced guard, and when the beetle ventures within her circumvallations, she pounces upon him and kills him. The Field-Cricket. Another insect of this family, the field-cricket [AcTieta camjjesiris), also forms burrows in the ground, in which it lodges all day, and comes out chiefly about sunset to pipe its evening song. It is so very shy and cautious, however, that it is by no means easy to discover either the insect or its biuTOw. " The childi-en in France amuse themselves with hunting after the field-cricket ; they put into its hole an ant fastened by a long hair, and as they di-aw it out the cricket does not fail to piu-sue it, and issue from its retreat. Pliny informs us it might be captured in a much more expeditious and easy manner. If, for instance, a small and slender piece of stick were to be thrust into the burrow, the insect, he says, would immediately get upon it for the pur- pose of demanding the occasion of the intrusion : whence arose the proverb, stidtior grillo (more foolish than a cricketj, applied to one who, ujjon light grounds, provokes his enemy, and falls into the snares which might have been laid to entrap him."| The Eev. Mr. White, who attentively studied their habits * Natural History of Selbome, ii. 82. t Entomologie, par R. A. E. 18mo., Pai-is, 1826, p. 168. 268 Insect Architecture. and manners, at first made an attempt to dig them out witli a spade, but without any great success ; for either the bottom of the hole was inaccessible, from its terminating under a large stone, or else in breaking up the ground the poor creature was inadvertently squeezed to death. Out of one thus bruised a great mmiber of eggs were taken, which were long and narrow, of a yellow colour, and covered with a very tough skin. More gentle means were then used, and these proved successful. A pliant stalk of grass, gently insinuated into the caverns, will probe their windings to the bottom, and bring out the inhabitant ; and thus the humane inquii-er may gratify his curiosity without injuring the object of it. When the males meet, they sometimes fight very fiercely, as Mr. White found by some that he put into the crevices of a dry stone wall, where he wished to have them settle. For though they seemed distressed by being taken out of their knowledge, yet the first that got possession of the chinks seized on all the others that were obtruded upon him with his large row of serrated fangs. With their strong jaws, toothed like the shears of a lobster's claws, they perforate and round their curious regular cells, having no fore-claws to dig with, like the mole -cricket. When taken into the hand, they never attempt to defend themselves, though armed with such formidable weapons. Of such herbs as grow about the mouths of their burrows they eat indiscri- minately, and never in the day-time seem to stir more than two or three inches from home. Sitting in the entrance of their caverns, they chirp all night as well as day, from the middle of the month of May to ^he middle of July. In hot weather, when they are most vigorous, they make the hills echo ; and, in the more still hours of darkness, may be heard to a very considerable distance. " Not many sum- mers ago," says Mr. White, " I endeavoured to transplant a colony of these insects to the terrace in my garden, by boring deep holes in the sloping turf. The new inhabitants stayed some time, and fed and sang ; but they wandered away by degrees, and were heard at a greater distance every morning ; so it appears that on this emergency they made use of their 'Burying Beetle. 269 wings in attempting to return to the spot from which they were taken.'* The manner in which these insects lay their eggs is rejjresented in the following figure, which is that of an insect nearly allied to the crickets, though of a different crenus. Aa-ida Terntcirora depositing her eggs. The usual position of the ovipositor is represented by dots. A more lahorious task is performed by an insect by no means uncommon in Britain, the burying beetle (Necro- jihorus vesjnllo), which may be easily recognized by its longish body, of a black colour, with two broad and irregularly indented bands of yellowish brown. A foreign naturalist, 2,1. Gleditsch, gives a very interesting account of its in- dustry. He had " often remarked that dead moles, when laid upon the ground, especially if upon loose earth, were almost sure to disappear in the course of two or three days, often of twelve hours. To ascertain the cause, he placed a mole upon one of the beds in his garden. It had vanished * 2\atiiral History of Selborne. 270 Insect Architecture. by the third morning ; and on digging where it had been laid, he found it buried to the depth of three inches, and under it four beetles, which seemed to have been the agents in this singular inhumation. Not perceiving anything par- ticular in the mole, he buried it again ; and on examining it at the end of six days, he found it swarming with maggots, apparently the issue of the beetles, which M. Gleditsch now naturally concluded had buried the carcase for the food of their future young. To determine these points more clearly, he put four of these insects into a glass vessel, half filled with earth and properly secured, and upon the surface of the earth two frogs. In less than twelve hours one of the frogs was interred by two of the beetles ; the other two ran about the whole day, as if busied in measui'ing the dimen- sions of the remaining corpse, which on the third day was also found buried. He then introduced a dead linnet. A pair of the beetles were soon engaged upon the bird. They began their operations by jmshing out the earth from under the body, so as to form a cavity for its reception ; and it was curious to see the efforts which the beetles made, by dragging at the feathers of the bird from below, to pull it into its grave. The male, having driven the female away, continued the work alone for five hours. He lifted up the bird, changed its place, turned it, and arranged it in the grave, and from time to time came out of the hole, mounted upon it, and trod it under foot, and then retired below, and pulled it down. At length, apparently wearied with this uninterrupted labom*, it came forth, and leaned its head upon the earth beside the bird, without the smallest motion, as if to rest itself, for a full hour, when it again crept under the earth. The next day, in the morning, the bird was an inch and a half under ground, and the trench remained open the whole day, the corpse seeming as if laid out upon a bier, surrounded with a rampart of mould. In the evening it had sunk half an inch lower, and in another day the work was completed, and the bird covered. M. Gleditsch con- tinued to add other small dead animals, which were all sooner or later buried ; and the result of his experiment Dung-BeeUe. 271 was, that in fifty days four beetles had interred, in the very small space of earth allotted to them, twelve carcases, viz., four frogs, three small birds, two fishes, one mole, and two grasshopi^ers, besides the entrails of a fish, and two morsels of the lungs of an ox. In another experiment, a single beetle buried a mole, forty times its own bulk and weight, in two days."* In the summer of 1826,- we found on Putney Heath, in Sm-rey, four of these beetles, hard at work in burying a dead crow, precisely in the manner described by M. Gleditsch. (J. E.) DimG-BEETLE. A still more common British insect, the dorr, clock, or dung-beetle {Geotrupes stercorarius), uses different materials for bui'ying along with its eggs. " It digs," to use the words of Kii'by and Spence, " a deep cylindrical hole, and caiTying down a mass of the dung to the bottom, in it deposits its eggs. And many of the species of the genus Ateuchus roll together wet dung into round pellets, deposit an egg in the midst of each, and when dry push them back- wards, by their hind feet, to holes of the sui'prising depth of three feet, which they have previously dug for their re- ception, and which are often several yards distant. The attention of these insects to their eggs is so remarkable, that it was observed in the earliest ages, and is mentioned by ancient writers, but with the addition of many fables ; as that they were all of the male sex ; that they became young again every year ; and that they rolled the pellets containing their eggs from sunrise to sunset every day, for twenty-eight days, without intermission."! " We frequently notice in our evening walks," says Mr. Knajjp, " the mui-muring passage, and are often stricken by the heedless flight of the great dorr-beetle [Geotrupes sterco- rarius), clocks, as the boys call them. But this evening my * Act. Acad. Berolin. 1752, et Gleditsch, Phys. Botan., quoted by Kirby and Spence, ii. 353. t Moufet, 153. Kirby and Spence, ii. 350. 272 Insect Architecture. attention was called to them in particular, by the constant passing of such a number as to constitute something like a little stream ; and I was led to search into the object of their direct flight, as in general it is irregular and seemingly inquisitive. I soon found that they dropped on some recent nuisance : but what powers of perception must these crea- tures possess, drawn from all distances and directions by the very little fetor which, in such a calm evening, could be diffiised around, and by what inconceivable means could odoui-s reach this beetle in such a manner as to rouse so inert an insect into action ! But it is appointed one of the great scavengers of the earth, and marvellously endowed with powers of sensation, and means of effecting this pur- pose of its being. Exquisitely fabricated as it is to receive impressions, yet probably it is not more highly gifted than any of the other innumerable creatures that wing their way around us, or creep about our paths, though by this one perceptible faculty, thus ' dimly seen,' it excites our wonder and surprise. How wondrous then the whole ! " The perfect cleanliness of these creatures is a very notable circumstance, when we consider that nearly their whole lives are passed in burrowing in the earth, and re- moving nuisances ; yet such is the admirable polish of their coating and limbs, that we very seldom find any soil ad- hering to them. The meloe, and some of the scarabaei, upon first emerging from their winter's retreat, are commonly found with earth clinging to them ; but the removal of this is one of the first operations of the creature ; and all the beetle race, the chief occupation of which is crawling about the soil, and such dirty employs, are, notwithstanding, remarkable for the glossiness of their covering, and freedom from defilements of any kind. But purity of vesture seems to be a principal precept of Nature, and observable through- out creation. Fishes, from the nature of the elen.eut in which they reside, can contract but little impurity. Birds are unceasingly attentive to neatness and lustration of their pliunage. All the slug race, though covered with slimy matter calculated to collect extraneous things, and reptiles, Tumhie-Dmiff Beetle. 273 are perfectly free from soil. The fui- and hair of beasts, in a state of liberty and health, is never iilthy or sullied with dirt. Some birds roll themselves in dust, and, occasionally, particular beasts cover themselves with mire ; but this is not from any liking or inclination for such things, but to free themselves from annoj^ances, or to prevent the bites of insects. Whether birds in preening, and beasts in di-essing themselves, be directed by any instinctive faculty, we know not ; but they evidently derive jjleasure from the operation, and thus this feeling of enjoyment, even if the sole motive, becomes to them an essential soui'ce of comfort and of health."* The rose or green chafer (^Cctonia aurata), which is one of our prettiest native insects, is one of the burrowers, and, for the pui'pose of depositing her eggs, digs, about the middle of June, into soft light ground. When she is seen at this operation, with her broad and delicate wings folded up in their shining green cases, speckled with white, it could hardly be imagined that she had but just descended from the air, or dropped down from some neighboui'ing rose. The proceedings of the Tumble-Dung Beetle of America (Scarabceus pilularius, Linn.) are described in a very interest- ing manner by Catesby, in his ' Carolina.' " I have," says he, " attentively admired their industry, and mutual assisting of each other in rolling their globular bails from the place where they made them to that of their interment, which is usually the distance of some yards, more or less. This they perform breech foremost, by raising their hind parts, and forcing along the ball with their hind feet. Two or three of them are sometimes engaged in trundling one ball, which, from meeting with impediments on account of the unevenness of the ground, is sometimes deserted by them. It is, how- ever, attempted by others with success, unless it happens to roll into some deep hollow or chink, where they are con- strained to leave it ; but they continue theii" work by rolling off the next ball that comes in their way. None of them * Jouni;il of a Naturalist, p. 311. 274 Insect Architecture. seem to know tlieir own balls, but an equal care for the whole appears to affect all the community. They form these pellets while the clung remains moist, and leave them to harden in the sun before they attempt to roll them. In their moving of them from place to place, both they and the balls may frequently be seen tumbling about the little eminences that are in their way. They are not, however, easily dis- couraged ; and, by repeating their attempts, usually surmoimt the difficulties." He further informs us that they " find out their subsistence by the excellency of their noses, which direct them in their flight to newly-fallen dung, on which they immediately go to work, tempering it with a proper mixtiu'e of earth. So intent are they always upon their employment, that, though handled or otherwise interrupted, they are not to be deterred, but immediately, on being freed, persist in their work without any apprehension of danger. They are said to be so exceed- ingly strong and active as to move about, with the greatest ease, things that are many times their own weight. Dr, Brichell was supping one evening in a planter's house of North Carolina, when two of them were conveyed, without his knowledge, under the candlesticks. A few blows were struck on the table, and, to his great surprise, the candle- sticks began to move about, apparently without any agency ; and his surprise was not much lessened when, on taking one of them up, he discovered that it was only a chafer that moved it." We have often found the necklace-beetle (Carabus monilis) inhabiting a chamber dug out in the earth of a garden, just sufficient to contain its body, and carefully smoothed and polished. From the form of this little nest, it would seem as if it were constructed, not by digging out the earth and removing it, but chiefly by the insect pushing its body forcibly against the walls. The beetles which we have found nestling in this manner have been all males; and therefore it cannot be intended for a breeding-cell ; for male insects are never, we believe, sufficiently generous to their mates to assist them in such labours. The beetle in question Cockcluifer. 275 appears to be partial to celery trenches (J. E.) ; probably from the loose earth of which they are coniposed yieldiiig, without much difficulty, to the pressm-e of its body. [Many of the subterranean larvaa which are turned up by the spade or the plough are the imperfect conditions of earth-burrowing beetles, and many of them are among the most insidious pests of the farmer, their ravages being all the more dangerous because they are unseen.] The most destructive, perhaps, of the creatm-es usually called grubs are the larvae of the may-bug or cockchafer (Mclolontha vulgaris), but too well known, particularly in the southern and midland districts of England, as well as in Ireland, where the grub is called the Connaught worm ;* but fortunately not abundant iu the north. We only once met with the cockchafer in Scotland, at Sorn, in Ayrshire. (J. E.) Even in the perfect state, this insect is not a little destructive to the leaves of both forest and fruit trees. In 1823, we remember to have observed almost all the trees about Dulwich and Camberwell defoliated by them ; and Salisbm-y says, the leaves of the oaks in Eichmond Park were so eaten by them, that scarcely an entire leaf was left. But it is in their previous larva state that they are most destructive, as we shall see by tracing their history. The mother cockchafer, when about to lay her eggs, digs into the earth of a meadow or corn-field to the depth of a span, and deposits them in a cluster at the bottom of the excavation. Eosel, in order to watch the proceedings, put some females into glasses half-filled with earth, covered with a tuft of gTass and a piece of thin muslin. In a fort- night, he found some hundreds of eggs deposited, of an oval shape and a pale-yellow colour. Placing the glass in a cellar, the eggs were hatched towai'ds autumn, and the grubs increased remarkably in size. In the follo\sang May they fed so voraciously that they required a fresh turf every second day ; and even this jjroving too scanty provender, he sowed in several garden pots a crop of peas, lentils, and salad, and Avhen the plants came up he put a pair of grubs in each pot ; * Bingley, Anim. Biog., vol. iii. p. 230. 276 Insect Architecture. and in this manner he fed them through the second and third years. During this period, they cast their skins three or foxir times, going for this purpose deeper into the earth, and bm-rowing out a hole where they might effect their change undisturbed ; and they do the same in winter, during which they become torpid and do not eat. Transformations of the Cockchafer {Melolcmtha vulgaris), a. Newly-hatched larvse, b, larva, one year old. c, the same larva at the second year of its growth, d, the same three years old. e, section of a bank of earth, containing the chrysalis of the fourth year. /, the chafer first emerging from the earth, g, the perfect chafer in a sitting posture, h, the same flying When the grub changes into a pupa, in the third autumn after it is hatched, it digs a similar burrow about a yard deep ; and when kept in a pot, and prevented from going deep enough, it shows great uneasiness and often dies. The perfect beetle comes forth from the pupa in January or Gruh of Cockchafer. 277 February ; but it is then as soft as it was whilst still a grub, and docs not acquire its hardness and colour for ten or twelve days, nor does it venture above ground before May, in the fourth year from the time of its hatching. At this time, the beetles may be observed issuing from their holes in the evening, and dashing themselves about in the air as if blind. During the three summers then of their existence in the grub state, these insects do immense injury, burrowing between the turf and the soil, and devouring the roots of grass and other plants ; so that the tui*f may easily be rolled off, as if cut by a turfing spade, while the soil underneath for an inch or more is turned into soft mould like the bed of a garden. Mr. Anderson, of Norwich, mentions having seen a whole field of fine flourishing grass so undermined by these grubs, that in a few weeks it became as dry, brittle, and withered as hay.* Bingley also tells us that " about sixty years ago, a farm near Norwich was so infested with cock- chafers, that the farmer and his servants affirmed they gathered eighty bushels of them ; and the grubs had done so much injury, that the court of the city, in compassion to the poor fellow's misfortune, allowed him twenty-five pounds."f In the year 1785, a farmer, near Blois, in France, employed a number of children and poor persons to destroy the cock- chafers at the rate of two liards a hundred, and in a few days they collected fourteen thousand.^ " I remember," says Salisbury, " seeing in a nursery near Bagshot, several acres of young forest trees, particularly larch, the roots of which were completely destroyed by it, so much so that not a single tree was left alive."§ We are doubtful, however, whether this was the grub of the cock- chafer, and think it more likely to have been that of tlie green rose-beetle (Cetonia aurata), which feeds on the roots of trees, * Phil. Trans., vol. sliv. p. 579. t -Anira. Biog., vol. iii. p. 233. J Anderson's Recr. in Agricult., vol. iii. p. 420. § Hints, p. 74. 278 Insect Architecture. CHAPTER XIV. ARCHITECTURE OF ANTS. MASON-ANTS. A LL the species of ants are social. There are none solitary, -^*- as is the case with bees and wasps. They are all more or less skilful in architecture, some employing masonry, and others being carpenters, wood-carvers, and miners. They consequently afford much that is interesting to naturalists who observe their operations. The genuine history of ants has only been recently investigated, first by Gould in 1747, and subsequently by Linnjeus, De Geer, Huber, and Latreille. Previous to that time their real industry and their imagined foresight were held up as moral lessons, without any great accuracy of observation ; and it is probable that, even now, the mixture of truth and error in Addison's delightful jjapers in the Guardian (Nos. 156, 157) may be more generally attractive than the minute relation of careful naturalists. Gould disproved, most satisfactorily, the ancient fable of ants storing up corn for winter provision, no species of ants ever eating grain, or feeding in the winter upon anything. It is to Huber the younger, however, that we are chiefly indebted for our knowledge of the habits and economy of ants ; and to Latreille for a closer distinction of the species. Some of the more interesting species, whose singular economy is described by the younger Huber, have not been hitherto found in this country. We shall, however, discover matter of very con- siderable interest in those which are indigenous ; and as our principal object is to excite inquiry and observation with regard to those insects which may be easily watched in oui* own gardens and fields, we shall chiefly confine ourselves to the ants of these islands. We shall begin with the labours of those native ants which may be called earth-masons, from their digging ia the ground, and forming structures with pellets of moistened loam, clay, or sand. Ma.