, 9*«-^" UNIVERSITY OF PITTSBURGH Darlington JVLemorial J-(ibrar] PUBLISHED UNDER THE SUPERINTENDENCE OF THE SO- CIETY FOR THE DIFFUSION OF USEFUL KNOWLEDGE. THE LIBRARY ENTERTAINING KNO^VLEDGE. INSECT ARCHITECTURE. ms LIBRARY OF ENTERTAINING KNOWLED IIN^SECT ARCHITECTURE BOSTON : LILLY & WAIT, COURT STREET. G. & C. i^H. Carvil, and E. Bliss, New York ; Carey & Hart, PhiladeJ- phia ; W. & J. Neal, Baltimore ; P. Tliompson, Washington ; K. Cruikshank, Georgetown ; W. W. Morrison, Alexandria ; R. D. Sanx- ay, Richmond ; W. H. Eerrett, Charleston, S. C. ; Mary Carroll, N. Orleans ; Odiorne & Smith, Mobile ; J. D. Ayres, Nashville, T. ; W. W. Worsley, Louiiville, Ky. ; IS. ^ G. Guilford, Cincinnati ; Little i^ Cum- mings, Albany; H. Howe, New Haven; S. Butler & Son, North- ampton ; Whipple & Lawrence, Salem ; Eli French & 6. C. Stevens, Dover; and S. Colman, Portland, 1830. ;iA\nv»«sj?i^,i\ ,j4s^4j; CONTENTS. ^ ^ ^ CHAPTER I. Introduction. . >>>Jnstruclion derivable from common tilings "..T ^Extraordinary numbers and varieties of Insects ^ Can he studied in every situation i^iS- Anecdotes . • • • Nl Cabinets useful but not indispensable . * Study of Insects does not narrow the mind . ,Tw Injuries and Benefits caused by Insects 't Use of names in Natural History . .V% Study of Insects fascinating to youth . \^^ Anecdote of a little girl ' p^ Beauty of Insects . . . • V Varieties in the economy of Insects . States of Insects .... Insects produced from e^SLS . Larva, Caterpillar, Grub, Maggot Pwpa, Chrysalis, Aureli a, Nymph . ,^^^i Imago, perfect Insect . . . • <5;^' CHAPTER II. Structures for protecting Eggs . * , , • , , , Rggs of Insects can bear great degrees of neat and colO Bees compared to our mechanics Mason-Wasps . . • • • S Curious proceedings of one at Lee . £j^ Her caution outwitted by a Fly ^O Structures of anotlier Mason-Wasp . ^ Her storing of live Caterpillars Mason-Bees ..... ^^ Nest of one on the wall of Greenwich Park !>>*. Clav-mine of Mason Bees at Lee !i^ Estimate of their labours |C Wall-Mason-Bees of France J^ Proceedings of the two-horned Mason Bee at Lee .rs Structures of Mason Bees . to Their restless disposition Miuing-Bees - • .-..-• ,. ' Their different proceedings in Britain and in i ranee CHAPTER III. krpentPi-Bees . • • - Methods of working History of one at Lee Violet Carpenter-Bee of France . Compared with our joiners Elder and Bramble Carpenter-Bees . A* Page 1 3 4 5 CONTENTS. Carpenfer-Wasps .... CuiioiH cocoon of Upholslfrpr-Bees .... Poppy-Flower Bt'e of Largs and of Bercy Taste of ilie linle arcliilecl* in ornament Cottoii-Grttlieriiig Bee Ro^e- Leaf Cutter Bee Her method of woikiiig Anecdote of St Fiancis Xavier CHAPTER IV Carder-Bees Meihnd of preparing and conveying their materials Ssriidure of iheir nests Lapid.iry-Hees Pertinacity in defending their nest Hnmble-B.'es Sirnciure of tlieir nests Social-^^■a^ps Nest founded by a single female Conipiired with the Burrowiiig-Owl Materials rasped off from wood JJifferent opiiiioiis of Naturalists Paper made by Wasps Structure of liie nest Extraordinary number of cells Hornet's nest . Tree-Wasps' nests in Ayrshire Hose shaped Wasps' nest Vertical Uasps' nest AV'a«p-paper compared with ours Card making Wasp ol" Cayenne CHAPTER V. Arcliitecdire of the Hive-Bee Discoveries from Aristomnchus to Maraldi and Huber jN'urse-Bees and Wax-\\orkers . Preparation of wax Erroneous account by the Abbe la Pluch Conjectures of Eleauiniir Discovery of John Hunter Experiments of ,M. Hiiber . Singular fac's l>y Mr \N'iston Dissections by Madlle Juriue and M. Latrtille Propolis ..... Opinions of Old Naturalists Discovery by Huber . Vaiiciijs uses of propolis Mf 'I'. A, Knight's observations Biskel for carrying on the thighs of Bees Process of loading Building of the cells Division of labour CONTENTS. Festooned curtain of \Vax-^^'orker3 CoiiiiiienceniPiit of the coinhs Hnhei's lii^iory of liis expeiinients Secretion of wnx Foiinclatiou of the first cell AVorkers extract their own wax View of the proceeding* ohslrncted CHAPTER VI. Form of the cells . •,,,•„ Mathematical problem solved by Bees Calculated by Maialdi and KcBriig Reasons for the form of tiie cells Referrt-d lo the form of the Bee Experiments of Huher Cells commenced in the foundation-wall Deepeiiiiis; of tiie cells Polishing by Nurse Bees Distance of the combs frntn each other Dr Barclay's discovery Irregularities in their workmansliip Anecdote from Dr Bevan Similar anecdote from Huber Symmetry in the architecture of Bees explained Curved combs . • • • Experiments of Huber . Size of male cells Cells enlarged when honey is plentiful The finishing of the cells . Varnished with propolis Strengthened with pissoceros Discovered bv Huber . Cells strengthened by the Bee-grubs Difficulties explained . Mistake of an American writer Curious experiment of Huber . Wild-Honey-Bees Wild-Bees of America, Ireland, Palestine Honey-guide of Africa Bee-hunting in America CHAPTER VII. Carpentry of Tree hoppers (Cicada) . Mistaken for Grass-hoppers Singular cutting instrument of the Tree-hoppei Double files of . . • Their Nests .... Saw.Fliea ..... Their ovipositor Structure of ... • Comb-toothed rasp, and saw . Grooves cut by it in the rose-tree . VIU CONTENTS. CHAPTER VIII. Leaf-Roltiiig-CttPrpill.irs Li l^.c-Le.if Roller . Ck-LealKollpr RosL- Leaf Roller Nettle-Leaf-Roller . Aletiioil of proceeding; Prob.ible ini-take concerning Sorrel-Lpaf-Rolier Admirable and painted hidy. Butterflies Mallow Biitt<^ifly of France WiMow-Lraf-Bondler Nest of Zii-zac Caterpillar Nesl of Glauville-Fritilliiry Experinieiil on gregarious Calerpillarj by Design in rolling leaves CHAPTER IX. Habitations fornipd of detached leaves The Poiidweed Tent-Maker Cliickweed Caterpillar^ nest Cypipf* purge Caterpillar's nest Durability of these slrnclnres Compared witli our arcliilecture iMo^f-cell of a Wall Caterpillar Caterpillar of Greenwich Park wall CHAPTER X. Caddi?-worins Jj^af and reed nests of Shell nrsts of Stone and sand nests of Nesl balanced with straws Carpenter-Caterpillars Caterpillar of GoatMolh Its winter nest Singular nest of Nest of the y^^eria in a poplar . Paper-nest of the PussMoili - How it escapes from its cell' Purple Capricorn-Beetle . Bark-building Caterpillar of the oak CHAPTER XI. Earlh-Mason-Caferpillars Outside walls of their nests Caterpillar of Ghost Rlotli F.xperiments of Keaumur Nests of Ephemera Grubs Similar nests in a willow slump Nests of the Cicindela-Reelle The Anl-Lion CONTENTS. Structure of the Grub . Formation of its traps lleflectioiis upon the economj' of Nature CHAPTER XII. Clothes-Moth Caterpillars . Vrtrieties ill the species M(>lhod» of destroying Mode of buildiiig Expeiiiiients upon Mii^.ralioiis of . Tent-MAi .g Caterpillars Mode of coustrueiiug these Experimeuls upon Tent upon a Nettle-leaf Stone-Mnson Caterpilliirs _ . 'I'heir singular proceedings Colony of, at Blackhealh Foundation of tlit-ir Tents An attempted robbery Mi:ff shaped Tents Tlieir utility Leaf-Milling Caterpillars On tlie leaf of the Monthly Rose-tree On the leaf of tiie Bramble On tlie leaf of the Priinrose Vine-leaf Miner On the leaf of the Alder Social Leaf-Miners Bark-mining Caterpillars - ' CHAPTER XIII. Structures of Crickets Housp-Cricket The Mole Cricket The Field-Cricket Mode of depositing eggs Beetles . . - ;»- . . The Burying-Beetle . -■ ' ^ The Dung-Beetle . , ■ . Its cleanliness . The Rose-Chafer . The Tumble-dung Beetle The Necklace-Beetle CHAPTER XIV. Architecture of Ants . Their genuine history begun by Gould Mason-ants .... Structures of Turf-Ants Winter nest of Yellow-Ants Sort of earth employed in building Proceedings of the Brown-Ant . IX Page 210 211 214 CONTENTS. Riift formed by American Ants Blind Ants .... Ki^lit proceedings of Ants Proceedings during rain Experiments . . . . History of a hibonring Ant, by M. Huber GlazHtl Artificial Foimicaries Section of a Mason-Ani's Experiments by J. li. . CHAPTER XV. Structures of the Wood-Ant>,or Pismires Materials employed . Coping of their nest Interior structure Glazed Formicary for experiments Their proceedings at night-fall . Carpenter-Anls Eininels, or Jet Ants Their galleries in Trees Extremely populous colony at Brock Dusky-Ants Foreign Ants Sugar-Ants of the West-Indies CHAPTER XVI. Structures of Wliite-Aiits, or Termites Their extraordinary comparative heigl Their mining operatioiit The Warrior (Termes (jillicosus) . Used as delicate food Commencement of their nests Royal chamber Nurseries Galleries and covert ways Turret-building Whitc-Anis, Singular form of their nests Whife-Ani!< of trees and timber l)eath-^^■atch CHAPTER XVJI. Spinnine-Caterpillars Maiiifdlrl advantages of spinning Slruiliire of theii legs and feet Side s)iiriicli- freshest and the most delightful parts of knowledge; the more do we learn to estimate rightly the extraor- dinary provisions and most abundant resources of a creative Providence; and the better do we appreciate our own relations with all the infinite varieties of JNTature, and our dependence, in common with the ephemeron that flutters its little hour in the summer sun, upon that Being in whose scheme of existence the humblest as well as the highest creature has its destined purposes. " If you speak of a stone," says St Basil, one of the Fathers of the Church, " if you speak of a fly, a gnat, or a bee, your conversation will be a sort of demonstration of His power whose hand formed them; for the wisdom of the workman is commonly perceived in that which is of little size. He who has stretched out the heavens, and dug up the bottom of the sea, is also He who has pierced a passage through the sting of the bee for the ejection of its poison." If it be granted that making discoveries is one of the most satisfactory of human pleasures, then we may without hesitation affirm, that the study of insects is one of the most delightllil branches of natural his tory, for it affords peculiar facilities for its pur- suit. These facilities are found in the almost inex- haustible variety which insects present to the entomolo- gical observer. As a proof of the extraordinary num- ber of insects within a limited field of observation, Mr Stephens informs us, that in the short space of forty days, between the middle of June and the beginning of August, he found, in the vicinity of Ripley, speci- mens of above two thousand four hundred species of insects, exclusive of caterpillars and grubs, — a number amounting to nearly a fourth of the insects ascertained to be indigenous. He further tells us, that among these specimens, although the ground had, in former seasons, been frequently explored, 4 INSECT ARCHITECTURE. there were about one hundred species altogether new^ and not before in any collection which he had in- spected, including several new genera; while many insects reputed scarce were in considerable plenty.* The locahties of insects are, to a certain extent, con- stantly 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, Avhich are plentiful one year, fiequently become scarce, or disappear altogether, the next — a fact strikingly illustrated by the uncommon alnindance, in 1826 and 1827, of the seven-spot lady-bird {Coc- cinella septempvnctafa), in the vicinity of London, though during the two succeeding summers this insect was comparatively scarce, while the small two- spot lady-bird [CoccincUa bipimctata) was plen- tiful. There is, perhaps, no situation in which the lover of nature and the observer of animal life may not find opportunities for increasing his store of facts. It is told of a state prisoner under a cruel and rigorous despotism, that when he was excluded from all com- merce 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 imi)rol)ability in the story. The operations of that jicrsecuted creature are among the most extraordinary exhibitions of me- chanical ingenuity; and a daily watching of the •workings of its instinct would beget admiration in a rightly constituted mind. The poor prisoner had abundant leisure for the speculations in which the spider's web would enchain liis 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 * Stephen's Illustrations, vol. i.. p. 72, note. INTRODUCTION. O own eyes. Want of leisure, and probably want of knowledge, have prevented us from following up the curiosity which for a moment was excited. And yet some such accident has made men Naturalists, in the hiorhest meaning of the term. Bonnet, evidently speaking of himself, says, " I knew a Naturalist, who, when he was seventeen years of age, having heard of the operations of the ant-lion, began by doubting them. He had no rest till he had examined into them; and he verified them, he admired them, he discovered new facts, and soon became the disciple and the friend of the Pliny of France*" (Reaumur.) It is not the happy fortune of many to be able to de- vote themselves exclusively to the study of nature, unquestionably the most fascinating of human em- ployments; but almost every one may acquire suffi- cient knowledge to be able to derive a high grati- fication 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, ex- pressly for the purpose of observing the insects we might meet with in the wood; but we had not got far among the bushes, when heavy rain came on. We immediately sought shelter among the boughs of some thick underwood, composed of oak, birch, and aspen; but we could not meet with a single insect, not even a gnat or a fly, sheltered under the leaves. Upon looking more narrowly, however, into the bushes which protected us, we soon found a variety of interesting objects of study. The oak abounded in galls, several of them quite new to us; while the ieaves of the birch and the aspen exhibited the cu- rious serpentine paths of the minute mining cater- pillars. When we had exhausted the narrow field of * Contemplation de la Nature, part ii. ch. 42. vot. IV. 1* b INSECT ARCIIITECTURE, 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 maimer two hours glided quickly and pleasantly away, by which time the rain had nearly ceased; and though we had been dis- appointed 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 will appear then, from the preceding observations, that cabinets and collections, though undoubtedly of the highest use, are by no means indispensable, as the observer of nature may find inexhaustible sub- jects 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 dis- appointed in the gratification which is thus with- in 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 edu- cated. The pleasures of childhood are generally supposed to be more exquisite, and to contain less alloy, than those of riper years; and if so, it must be because then every thing appears new and dressed in fresh beauties: while in manhood, and old age, whatever has frequently recurred begins to wear the tarnish of decay. The study of nature affords us a succession of " ever new delights," such as charmed us in childhood, when every thing had the attractions of novelty and beauty; and thus the mind of the naturalist may have its own fresh and vigorous * The original observations in this \ olume whicli are marked by the initials J. R., are by J. Hennic, A.RI., A.L.S., Lee, Kent. INTRODUCTION. < thoughts, even while tlie infirmities of age weigh down the body. It has been objected to the study of insects, as well as to that of Natural History in general, that it tends to withdraw the mind from subjects of higher moment; that it cramps and narrows the range of thought ; and that it destroys, or at least weakens, the finer creations of the fancy. Now, we should allow this objection in its fullest extent, and even be disposed to carry it further than is usually done, if the collecting of specimens only, or, as the French expressively call them, chips (echantiUons)j be called a study. But the mere col- lector is not, and cannot be, justly considered as a naturalist; and, taking the term naturalist in its en- larged sense, we can adduce some distinguished in- stances in opposition to the objection. Rousseau, for example, was passionately fond of the Linnsean botany, even to the driest minutiaj of its technicalities; and yet it does not appear to have cramped his mind, or impoverished his imagination. If Rousseau, how- ever, 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 where all enthusiastic naturalists. We wish particularly to insist upon the example of Gray, because he was very partial to the study of insects. It may be new to many of our readers, who are familiar with the Elegy in a Country Church-yard, to be told that its author was at the pains to turn the characteris- tics of the Linnaean orders of insects into Latin hexameters, the manuscript of which is still preserved in his interleaved copy of the " Systema Naturae." Further, to use the somewhat exaggerated words of Kirby and Spence, whose work on Fntomology is one of the most instructive and pleasing books on a INSECT ARCHITECTURE. the science, " Aristotle among the Greeks, and Phny the Elder among the Romans, may be denominated the fathers of Natural History, as well as the greatest philosophers of their day; yet both these made insects a principal object of their attention: and in more recent times, if we look abroad, what names, greater than those of Redi, Malpighi, Vallisnieri, Swammerdam, Leenwenhoek, Rt aumur, Linngeus, De Geer, Bonnet, and the Hubers? and at home, what philosophers have done more honour to their country and to human nature than Ray, Willoughby, 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: — " O! would the sons of men once think their eyes And reason given them but to study Flies! See Nature in some partial, narrow shape, And let the Author of the whole escape; Learn but to trifle; or, who most observe, To wonder at their Maker not to serve, "t Thus exclaims the Goddess of Dulness, sweeping into her net all those who study nature in detail. But if the matter were rightly appreciated, it would be evident that no part of the works of the Creator can be without the deepest interest to an inquiring mind; and that a portion of creation, which exhibits such extraordinary manifestations of design as is shewn by insects, must have attractions for the very highest understanding. An accurate knowledge of the properties of insects * Introduction to Entomology, vol. i. t Dunciad, book iv. INTRODUCTION. if is of great importance to man, merely with relation to his own comfort and security. The injuries which they inflict upon us are extensive and complicated ; and the remedies which we attempt, by the destruction of those creatures, both insects, birds, and quadrupeds, who keep the ravagers in check, are generally ag- gravations 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 philo- sophical 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 manu- script. Many provinces of Spanish America can- not, in consequence, shew a written document of a hundred years' existence. " What developement," he adds, " can the civilization of a people assume, if there be nothing to connect the present with the past — if the depositories of human knowledge must be constantly renewed — if the monuments of genius and wisdom cannot be transmitted to posterity ?"* Again, there are beetles which deposit their larvee * Humboldt, Voyage, lib. vii., ch. 20. 10 INSECT ARCHITECTURE. in trees, in such formidable numbers, that whole forests perish, beyond the posver of remedy. The pines of the Hartz have thus been destroyed to an enormous extent; and in North America, at one place in South Carohna, at least ninety trees in every hundred, upon a tract of two thousand acres, were swept away by a small, black, winged bug. And yet, according to Wilson, the historian of American birds, the people of the United States were in the habit of destroying the red-headed woodpecker, the great enemy of these insects, because he occasionally spoilt an apple.* The same delightful writer, and true natu- ralist, speaking of the labours of the ivory -billed wood- pecker, says, " would it be believed that the larvae of an insect, or fly, no larger than a grain of rice, should silently, and in one season, destroy some thousand acres of pine trees, many of them from two to three feet in diameter, and a hundred and fifty feet high ? in some places the whole woods, as far as you can see around you, are dead, stripped of the bark, their wintry-looking arms and bare trunks bleaching in the sun, and tumbling in ruins before every blast. "| The subterraneous larva of a species of beetle {Zabrus gibbus) has often caused a complete failure of the seed-corn, as in the district of Halle in 18 12. J The corn-weevil, which extracts the flour from grain, leaving the husk behind, will destroy the contents of the largest storehouses in a very short period. The wire-worm, and the turnip-fly, are dreaded by every farmer. The ravages of the locust are too well kno\\n not to be at once recollected, as an example ol' the formidable collective power of the insect race. The white ants of tropical countries sweep awav whole villages, with as much certainty as a fire or an inun- » Amer. Orinth., i.,p. 144. t lb., iii., p. 21. i Rlumenbach. JNTRODUCTION. 11 dation; and ships even have been destroyed by these indefatigable repubUcs. Our own docks and em- bankments have been threatened by such minute ravagers. The enormous injuries which insects cause to man may thus be held as one reason for ceasing to consider the study of them as an insignificant pursuit; for a knowledge of their structure, their food, their enemies, and their general habits, may lead, as it often has led, to the means of guarding against their injuries. At the same time we derive from them both direct and indirect benefits. The honey of the bee, the dye of the cochineal, and the web of the silk worm, the advantages of which are obvious, may well be balanced against the destructive propensities of in- sects which are offensive to man. But a philosophi- cal study of natural history will teach us, that the direct benefts which insects confer upon us are even less important than their general uses in maintaining the economy of the world. The mischiefs which result to us from the rapid increase and the activity of insects, are merely results of the very principle by which they confer upon us numberless indirect ad- vantages. Forests are swept away by minute flies; but the same agencies relieve us from that extreme abundance of vegetable matter, which would render the earth uninhabitable, were this excess not periodi- cally destroyed. In hot countries, the great business of removing corrupt animal matter, which the vulture and the hyaena imperfectly perform, is effected with certainty and speed by the myriads of insects that spring from the eggs deposited in every carcass, 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 princi- 12 INSECT ARCHITECTURE, pie regulates even the increase of particular species of insects themselves. When aphides are so abun- dant that we know not how to escape their ravages, flocks of lady-birds instantly cover our fields and gardens to destroy them. Such considerations as these are thrown out to shew that the subject of insects has a great philosophical importance — and what portion of the works of Nature has not ? The habits of all God's creatures, whether they are noxious, or harmless, or beneficial, are worthy objects of our study. If they affect ourselves, in our health or our possessions, whether for good or for evil, an additional impulse is naturally given to our desire to attam a knowledge of their properties. Such studies form one of the most interesting occu- pations which can engage a rational and inquisitive mind; and, perhaps, none of the employments of human life are more dignified tlian the investigation and survey of the workings and the ways of TSature in the minutest of her productions. The exercise of that habit of observation which can alone make a naturahst — " an out-of-door natu- ralist," as Daines Barrington called himselt^ — is well calculated to strengthen even the most practical and merely useful powers of the mind. One of the most valuable mental acquirements is the power of discri- minating among things which differ in many minute points, but whose general similarity of ajipearance usually deceives the common observer into a belief of their identity. Entomology, in this point of view, is a study peculiarly adapted for youth. According to our experience, it is exceedingly difficult for persons arrived at manhood to acquire this power of discri- mination; but in early life, a little care on the part of the parent or teacher will render it comparatively easy. In this study the knowledge of things should go along with that of words. " It' names perish," says INTRODUCTION. 13 Lmnteus, " the knowledge of things perishes also;"* and without names, how can any one communicate to another the knowledge he has acquired relative to any particular fact, either of physiology, habit, utility, or locality ? On the other hand, mere catalogue learning is as much to be rejected as the loose generalizations of the despisers of classification and nomenclature. To name a plant, or an insect, or a bird, or a quadruped rightly, is one step towards an accurate knowledge of it; but it is not the knowledge itself It is the means, and not the end, in natural history, as in every other science. If the bias of opening curiosity be properly di- rected, there is not any branch of natural liistory so fascinating to youth as the study of insects. It is, indeed, a common practice in many fainilies, to teach children, from the earliest infancy, to treat the greater number of insects as if they were venomous and dangerous, and, of course, meriting to be de- stroyed, or, at least, avoided with horror. Associa- tions are by this means linked with the very ap- pearance of insects, which become gradually more inveterate with advancing years ; provided, as most frequently happens, the same system be persisted in, of avoiding or destroying almost every insect which is unlucky enough to attract observation. How much rational amusement and innocent pleasure is thus thoughtlessly lost ; and how many disagreable feel- ings are thus created, in the most absurd manner ! " In order to shew," says a writer in the Magazine of Natural History, " 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 ■* Nomina si pereant, perit et cognitio rerum. VOL. iv. 2 14 INSECT ARCHITECTURE, departments of natural history. Our friend's children^ a boy and a 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 an example, when just beginning to walk alone, encountered one day a large staphylinus {Goerius olensl Stephens ; vulgo the deviVs coach- horse), which she fearlessly seized, and did not quit her hold, thougli the insect grasped one of her lingers in his formidable jaws. The mother, who was by, knew enough of the insect to be rather alarmed for the consequences, though she prudently concealed her feelings from the child. She did well ; for the insect was not strong enough to break the skin, and the child took no notice of its attempts to bite her finger. A whole series of disagreeable associations with this formidable-looking family of insects was thus averted, at the very moment when a different mode of acting on the part of the mother would have produced the contrary effect. For m-are 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 had 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 hap- pened 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 ' every- thing that crcepeth on the earth :' and though she afterwards returned to her paternal home, no persua- sion nor remonstrance could ever again persuade her to touch a common beetle, much less a staphylinus, with its tail turned up in a threatening attitude, and its formidable jaws ready extended for attack or defence." INTRODUCTION. 15 We do not wish that children should be encouraged to expose themselves to danger, in their encounters with insects. They should be taught to avoid those few which are really noxious — to admire all — to injure none. The various beauty of insects — their glittering colours, their graceful forms — supphes an inexhaus- tible source of attraction. Even the most formidable insects, both in appearance and reality, — the dragon- fly, which is perfectly harmless to man, and the wasp, whose sting every human being almost instinctly shuns, — are splendid in their appearanbe, and are painted with all the brilliancy of natural hues. It has been remarked, that the plumage of trophical birds is not superior in vivid colouring to what may be observed in the greater number of butterflies and moths.* " See !" exclaims Linnseus, " the krge, elegant painted wings of the butterfly, four in num- ber, covered with delicate feathery scales ! With these it sustains itself in the air a whole day, rivaUing the flight of birds and the brilliancy of the peacock. Consider this insect through the wonderful progress of its life, — how different is the first period of its being fi-om the second, and both from the parent insect ! Its changes are an inexplicable enigma to us : we see a green caterpillar, furnished with sixteen feet, feeding upon the leaves of a plant ; this is changed into a chrysalis, smooth, of golden lustre, hanging suspended to a fixed point, without feet, and subsisting without food ; this insect again undergoes another transformation, acquires wings, and six feet, and becomes a gay butterfly, sporting in the air, and living by suction upon the honey of plants. What has Nature produced more worthy of our admiration than such an animal coming upon the stage of the * Miss Jervym's Butterfly Collector, p. 11. 16 INSECT ARCHITECTURE, world, and playing its part there under so many dif- ferent masks ?" The ancients were so struck with the transformations of the butterfly, and its revival from a seeming temporary death, as to have consi- dered it an emblem of tlie soul, the Greek word ■<^vx,fi signifying both the soul and a butterfly ; and it is for this reason that we find the butterfly intro- duced into their allegorical sculptures as an emblem of immortality. Trifhng, therefore, and. perhaps con- temptible, as to the unthinking may seem the study of a butterfly, yet when we consider the art and me- chanism displayed in so minute a structure, — the fluids circulating in vessels so small as ahnost to escape the sight — the beauty of the wings and covering — and the manner in which each part is adapted for its peculiar functions, — we cannot but be struck with wonder and admiration, and allow, with Paley, that " tlie 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 entomologist 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 wonderftil -saricty of structure in this portion of the creation ; and, above all, to trace the beautiful gradations by which one species runs into another. Their difierenccs 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 INTRODUCTION. 17 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 ditierences of structure, form, and colouring, he is not less interested in the in- vestigation of habits and economy; and in this respect the insect world is inexhaustibly rich. We find herein examples of instinct to parallel those of all the larger animals, whether they are solitary or social; and innumerable others besides, altogether unlike those manifested in the superior departments of animated nature. These instincts have various directions, and are developed in a more or less striking manner to our senses, according to the force of the motive by which they are governed. Some of their instincts have for their object the preservation of insects from external attack; some have reference to procuring food, and involve many remarkable stratagems; some direct their social economy, and regulate the condition under which they live together either in monarchies or republics, their colonizations, and their migrations: but the most powerful instinct which belongs to insects has regard to the preservation of their species. We find, accordingly, that as the ne- cessity for this preservation is of the utmost importance in the economy of nature, so for this especial object many insects, whose offspring, whether in the egg or the larva state, are peculiarly exposed to danger, are endued with an almost miraculous foresight, and with an ingenuity, perseverance, and unconquerable industry, for the purpose of avoiding those dangers, which are not to be paralleled even by the most singu- lar efforts of human contrivance. The same ingenuity which is employed for protecting either eggs, or ca- terpillars and grubs, or pupte and chrysahdes, is also exercised by many insects for their own preservation against the changes of temperature to which they are exposed, or against their natural enemies. Many vol.. TV. '2* 18 INSECT ARCHITECTURE. species employ those contrivances during the period of their hybernation, or Avinter-sleep. For all these purposes some dig holes in the earth, and form them into cells; others build nests of extraneous substances, such as bits of wood and leaves; others roll up leaves into cases, which they close with the most curious art; others build a house of mud, and line it with the cotton of trees, or the petals of the most delicate flowers; others construct cells, of secretions from their own bodies; others form cocoons, in which they undergo their transformation; and others dig subterraneous galleries, which, in complexity of ar- rangement, in solidity, and in complete adaptation to their purposes, vie with the cities of civilized man. The contrivances by which insects effect these ob- jects have been accurately observed and minutely de- scribed, by patient and philosophical inquirers, who knew that such employments of the instinct with which each species is endowed by its Creator offered the most valuable and instructive lessons, and opened to them a wide field of the most delightful study. The construction of their habitations is certainly among the most remarkable peculiarities in the economy of insects; and it is of this subject that we propose to treat under the general name, which is sufficiently applicable to our purpose, of IiNsect Architecture. INTRODUCTION. In the descriptions which we shall give of Insect Architecture, we shall employ as few technical words as possible; and such as we cannot well avoid, we shall explain in their places: but, since our subject chiefly relates to the reproduction of insects, it may be useful to many readers to introduce here a brief description of the changes which they undergo. It was of old believed that insects were produced spontaneously by putrefying substances; and Virgil gives the details of a process for creating a swarm of bees out of the carcase of a bull: but Redi, a cele- brated Italian naturalist, proved by rigid experiments that they are always, in such cases, hatched from eggs previously laid. Most insects, indeed, lay eggs, though some few are viviparous, and some, like serpents, propagate both ways. The eggs of insects are very various in form, and seldom shaped like those of birds. We have here figured those of several species, as they appear under the microscope. Eg-g-s of Insects — Magnified. 20 INSECT ARCHITECTURE. When an insect first issues fi-om the egg, it is called by naturalists larva, and, popularly, a caterpillar, a grub, or a maggot. The distinction, in popular lan- guage, seems to be, that caterpillars are produced Irom the eggs of moths or butterflies; grubs, from the eggs of beetles, bees, wasps, Stc; and maggots (which are without feet) from blow-flies, house-tlies, cheese-flies, &c., though this is not very rigidly ad- hered to in common parlance. JVIaggots are also sometimes called ^vorins, 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. Larvae are remarkably small at first, but grow- rapidly The full-grown caterpillar of the goat-moth {Cossus ligniperda) is thus seventy-two thousand limes heavier than when it issues from the ess\ and INTRODUCTION. 21 ^\it maggot of the blow-fly is, in twenty-four hours, one hundred and fifty-five times heavier than at its birth Some larvoe have feet, others are without: none have wings. They cannot propagate. They feed voraciously on coarse substances; and as they increase in size, which they do very rapidly, they cast their skins three or four times. In defending themselves from injury, and in preparing for their change by the con- struction of secure abodes, they manifest great inge- nuity and mechanical skill. The figines on the pre- ceding page, exemplify various forms of insects in this stage of their existence. When larvse are full grown, they cast their sldns for the last time, undergo a complete change of form, and, with a few exceptions, cease to eat, and remain nearly motionless. When an insect, after this change, does not lose its legs, or continues to eat and move, it is popularly called a JYijmph; and when the inner skin of the larva is converted into a membranous or leathery covering, which wraps the insect closely up hke a mummy, it is termed Pupa, from its resem- blance to an infant in swaddling bands. From the pupae of many of the butterflies appearing gilt as if 22 INSECT ARCHITECTURE. with gold, the Greeks called them Chrysalides, and the Romans JlurelicB, and hence naturalists frequently call a pupa chrijsalis, even when it is not gilt. We shall see, as we proceed, the curious contrivances re- sorted to for protecting insects in this helpless state. After a certain time, the insect which has re- mained in its pupa-case, like a mass of jelly without shape, is gradually preparing for its hnal change, when it takes the form of a perfect insect. This state was called by Linnaeus, Imago, because the insect, having thrown oft' its mask, becomes a per- fect image of its species. Of some, this last por- tion of their existence is very short, others hve Insects in the Imago or perftct state. INTRODUCTION. 23 through a year, and some exist for longer periods. They feed Hghtly, and never increase in size. The chief object of all is to perpetuate their species, after which the greater number quickly die. It is in this state that they exercise those remarkable instincts for the preservation of their race, which are exhibited in their preparations for the shelter of their eggs, and the nourishment of their larvae. The foregoing are examples of insects in the imago, or perfect state. Chapter II. Structures for protecting Eggs.— Mnson-Wasps ; Mason-Bees; Mining The provisions which arc made by the different species of insects for protecting their eggs, appear in many cases to be admirably proportioned to the Idnd of danger and destruction to which they may be ex- posed. The eggs themselves, indeed, are not so liable to depredation and injury as the young brood hatched from them; for, like the seeds oT plants, they are capa- ble 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 ex- periment upon tadpoles and frogs, and found they all died at 111°. Silk-worms died at a temperature of 108°, while their eggs did not entirely cease to be fertile till 144°. The larvre of flesh-flies perished, while the eggs of the same species continued fertile, at about the same comparative degrees of heat as in the preceding instances. Intense cold has a still less effect upon eggs than extreme heat. Spallanzani ex- posed the eggs of silk-worms to an artificial cold 23° below zero, and yet, in the subsequent spring, they all produced caterpillars. Insects almost invariably die at the temperature of 14°, that is at 18° below tho freezing point.* The care of insects for the pro- * See Spallanzani's Tracts, l)y Dalycl, vol. i. MASON-WASPS. 25 tectiori of their eggs is not entirely directed to their preservation in the most favourable temperature for being hatched, but to secure them against the nume- rous enemies which would attempt their destruction; and, above all, to protect the grubs when they are first developed, from those injuries to which they are peculiarly exposed. Their prospective contrivances for accomplishmg 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, thovigh in many respects these are not interior to the others in dis- plays of ingenuity and skill. We admire the social bees, labouring together for one common end, in the same way that we look with delight upon the great division of labour in a well-ordered manufactory. As in a cotton-mill, some attend to the carding of the raw material, some to its formation into single threads, some to the gathering these threads upon spindles, others to the union of many threads into one, — ail labouring with invariable precision because they" attend to a single object; — so do we view with delight and wonder the successive steps by which the hive-bees bring their beautiful work to its com- pletion,— striving, by individual efforts, to accomphsh their general task, never impeding each other by use- less assistance, each talking a particular department, and each knowing its own duties. We may, how- ever, not the less admire the solitary wasp or bee, who begins and finishes every part of its destined work; just as we admire the ingenious mechanic who perfects something useful or ornamental entirely by the labour of his own hands, — whether he be the patient Chinese carver, who cuts the most elaborately decorated boxes out of a sold piece of ivory, or the VOL. IV. 3 il6 INSECT ARCHITECTURE. turner of Europe, who produces every variety of elegant form by the skilful application of the simplest means. Our island abounds with many varieties of solitary wasps and bees; and their nests may therefore be easily discovered by those who, in the proper seasons, are desirous ot observing the pecuharities of their Jirchitecture. Mason-Wasps. In September, 1828, a common species of solitary mason-wasp {Odynerus, Latr.) was observed by us* Odynenis — Natural size. on the east wall of a house at Lee, in Kent, very busy in excavating a hole in one of the bricks, about five feet from the ground. Whether there might not have been an accidental hole in the brick, before the wasp commenced her labours, is unknown, as she had made considerable progress in the work when first observed; but the brick was one of the hardest of the yellow sort made in this neighbourhood. The most remarkable circumstance in the process of hewing into the brick, was the care of the insect in re- moving to a distance the fragments which from the time to time she succeeded in detaching. It di dnot ap- pear to suit her design to wear down the brick, par- ticle by particle, as the furniture beetle {Anohium pertinax) does, in making its pin-hole galleries in old wood. Our wasp-architect, on the contreiry, by of her strong tranchant -toothed jaws, severed * J. R MASON-WASPS. 27 Mandibles — Jaws of Muson-Wasp. — Greatly magnified. a piece usually about the bigness of a mustard-seed. It might have been supposed that these fragments would have been tossed out of the hole as the work proceeded, without further concern ; as the mole tosses above ground the earth which has been cleared out of its subterranean gallery. The wasp was of a different opinion ; for it was possible that a heap of brick chips, at the bottom of the wall, might lead to the discovery of her nest by some of her enemies; particularly by one or other of the numerous tribe of what are called ichneumon flies. This name is given to them, from the similarity of their habit of destroying eggs to that of the little animal which proves so formidable an enemy to the multiphcation of the crocodile of Egypt. They may be also denominated cuckoo flies, because, like that bird, they thrust their egg into the nest of another species. These flies are continually prowling about and prying into every corner, to find, by stealth, a nidus for their eggs. It might have been some such consideration as this which induced the wasp to carry off the fragments as they were successively detached. That concealment was the motive, indeed, was proved ; for one of the fragments which fell out of the hole by 28 INSECT ARCHITECTURE. accident, she immediately sought for at the bottom of the wall, and carried ofFliliethe rest. It was no easy matter to get out one of the fragments, as may readily be conceived when the size of the insect is compared with that of the entrance, of Avhich this (U) 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, ^nd re- treating backwards, that the matter could be accom- plished ; 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, aiid she generally returned to her task m 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 {ew live spiders or caterpillars, for the young when hatched, — a process which was first observed by Ray and Willoughby*, but which has since been frequently ascertained. ' In the present instance, this peculiarity was not seen ; but the little architect was detected in closing up the entrance, which was formed of a layer of clay more than double the thickness of the interior lining. In jVo- vember following; we liewed 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 flies {Tuchina larvurum}) — probably a common species very similar to the house-fly, but * Ray, Hist. Insect. 254. MASON-WASPS. 29 Cuclcoo-Fhj—Tackina larvarum ?) -Natural size . jather larger, which deposited an egg there ; and the grub hatched from it, after devouring one of the wasp- grubs, formed itself a cocoon (o), as did the other Mason-frasp''s Nest and Cocoons.— About one-third the natural size. undevoured grub of the wasp (6). Both awaited the return of summer to change into winged irsects, burst their cerements, and proceed as their parents did. Mason-Wasp—(Odynerls murarius)- — Natural size. Another mason wasp {Odyneriis murarius, Latr.) differing httle in appearance from the former, may often be seen frequenting sandy banks exposed to the sun, and constructing its singular burrows, VOL. IV. 3* 30 INSECT ARCHITECTURE. The sort of sand-bank which it selects is hard and compact ; and though this may be more difficult to penetrate, the walls are not hable 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 recourse, as he ascertained, to the ingenious device of moistening it by letting fall two or three drops of fluid from their mouth, which rendered the mass ductile, and the separation of the grains easy to the double pickaxe of the little pioneers. >, When this wasp has detached a few grains of the moistened sand, it kneads them together into a pellet about the size of one of the seeds of a goose- berry. With the first pellet which it detaches, it lays the foundation of a round tower, as an out- work, immediately over the mouth of its nest. Every pellet which it afterwards carries off from the interior is added to the ^\all of this outer round tower, which advances in height as the hole in the sand increases in depth. E\ery two or three minutes, however, during these operations, it takes a short excursion, for the purpose, probably, of replenishing its store of fluid wherewith to moisten the sand. Yet so little time is lost, that Reaumur 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 hcigiit this round tower is perpendicular ; but towards the summit it bends into a curve, corresponding to the bend of the insect's body, which, in all cases of insect architecture, is the model followed. The pellet which form the walls of the tower are not very nicely joined, and numerous vacuities are \ei\ MASOiN-EEES. 31 Nests, <^c. of Mason-Wasps. — About half the natural size.— a The tower of the nest. 6 The entrance after the tower is re- moved, c The cell, rf The cell, with a roll of caterpillars pre- pared for the larva. between them, giving it the appearance of fillagree work. That it should be thus shghtly built is not surprising, for it is intended as a temporary structure for protecting the insect while it is excavating its hole; and as a pile of materials, well arranged and ready at hand, for the completion of the interior building, — in the same way that workmen make a regular pile of bricks near the spot where they are going to build. This seems, in fact, to be the main design of the tower, which is taken down as expedi- tiously as it had been reared. Reaumur thinks, that by piling in the sand which has previously been dug out, the wasp intends to guard its progeny for a time fi-om 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 32 INSECT ARCniTECTUKE. out after a tower was completed. By raising a tower of the materials which she excavates, the wasp produces the same shelter from external heat, as a human creature would who chose to inhabit a deep cellar of a high house. She further protects her progeny from the ichneumon fly, as the engineer con- structs an outwork to render more dithcult the ap- proach of an enemy to the citadel. Reaumur 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 aiLxious to invade. The mason-wasp does not furnish the cell she has thus constructed with pollen* and honey, like the solitary bees, but with living caterpillars, and these always of the same species, — being of a green colour, and without feet. She fixes the caterpillars together in a spiral column : they cannot alter their position, although they remain alive. They are an easy prey to their smaller enemy ; and when the grub has eaten them all up, it spins a case, and is transformed into a nymph, 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 careftil to lay in the exact quantity of provision A\hich 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 under- going a change into another state, in which he re- quires no Ibod. 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 "\\ ithout increase or cor- * The prolific powder of flowerg. MASON BEES. 33 ?\iption till their destroyer has gradually satisfied the necessities of his being. " All that the worm of the wasp," says R'^-aumur, " has to do in his nest, from his birth to his transformation, is to eat." There is another species of wasp wliich does not at once en- close 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.* , Mason-Bees. It would not be easy to find a more simple, and, at the same time, ingenious specimen of insect archi- tecture, than the nests of those species of solitary bees, which have been justly called mason-bees [Megachile, Latreille.) 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 ground, we discovered,! 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 hand- ful of wet road-stuff had been taken from a cart-rut and thrown against the wall; though, upon closer inspection, the cake contained more small stones * Bonnet, Contemplation, &c. 1. xii. c. 41. + J. R. 34 INSECT ARCHITECTURK. Mason-Bee— (Anthopho rtj.—Natural eiic. than usually occur in the mud of the adjacent cart- ruts. We should, m fact, have passed it by A\ithout notice, had there not been a circular hole on one^ide of it, indicating the perforation of some insect. "" Thi Exterior 7ca!! of Mason-Bet's nest. 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 poHshed, and of the colour of plaster of Paris, but stained in various places A\ith 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 v>as drawn, and which, as we supposed, had just changed from the pupa into the winged state, in consequence of tlie uncommon mildness of the weather. The one which had occupied the adjacent cell MASON-BEES. 35 had, no doubt, already dug his way out of its prison, and would probably fall a victim to the first frost. Our nest contained only two cells — perhaps frora there not beinor room between the bricks for more. Cells of a Mason-Bee (Anthaph ) — One third the natural size. An interesting account is given by Reaumur of ano- ther mason-bee (J\ft?o-ac/ii/e miiraria), selecting earthy sand, grain by grain; her gluing a mass of these toge- ther 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 Reaumur describes liis 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.* It was a bank of brown clay, facing the east, and close by the margin of the river Ravensbourn, at Lee, in Kent. The frequent resort of the bees to this spot attracted the attention of some workmen, who, deceived by their resemblance to wasps, pointed it out as a wasp's nest; though they were not a little surprised to see so numerous a colony at this early season. As the bees had dug a hole in ther bank. JR. 36 l.NbECT ARCHITECTUKE, where they were incessantly entering and re-appear- ing, we were of opinion that they were a pecuUar sort of the social earth bees {Bombus). On ap- proaching 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 ob- serve 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 con- cluded that they were busy excavating a hollow for their nest, and carrying oft' the refuse to prevent dis- covery. The mouth of the hole was overhung, and partly concealed by a large pebble. This we removed, cind 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 as- siduously digging and removing the clay. It became obvious, therefore, from their thus changing place, that they were not constructing a nest, but merely quarrying for clay as a building material. By catching one of the bees {Osmia hicornis) when it was loaded with its burden, we ascertained that the clay was not only carefully kneaded, but was also more moist than the mass from which it had been taken. The bee, therefore, in preparing the pellet, which was nearly as large as a garden pea, had moistened it with its saliva, or some similar fluid, to render it, we may suppose more tenacious, and better fitted I'or build- ing. The reason of their digging a hole, instead of taking clay indiscriminately from the bank, appeared to be for the purpose ol' economizing their saliva, as MASON-BEES. 37 the weather was dry, and the clay at the surface was parched and hard. It must have been this circum- stance which induced them to prefer digging a hole, as it were in concert, though each of them had to build a separate nest. The distance to which they carried the clay was probably considerable, as there was no wall near, in the direction they all flew towards, upon which they could build; and in the same direction also, it is worthy of remark, they could have procured much nearer the very same sort of clay. Whatever might be the cause of their preference, we could not but admire their extraordinary industry. It did not require more than half a minute to knead one of the pellets of clay; and from their frequent returns, probably not more than five minutes to carry it to the nest, and apply it, were wanted. From the dryness of the weather, indeed, it was in- dispensable 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 v/e estimate that it must take several hundred pellets of clay for its completion. If a bee work fourteen or fiiteen hours a day, there- fore, carrying ten or twelve pellets to its nest every hour, it will be able to finish the structure in about two or three days; allowing some hours of extra time for the more nice workmanship of the cells in which the eggs are to be deposited, and the young grubs reared. That the construction of such a nest is not a merely agreeable exercise to the mason-bee has been sufficiently proved by M. Du Hamel. He has ob- served a bee {Mcgachile rnurari'a) 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 VOL. IV. 4 38 INSECT ARCHITECTURE, 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 re- sistance was an indisposition to further labour. The trial of strength was probably, sometimes, of as little use in establishing the right as it is amongst man- kind; and the proper owner, exhausted by her efforts, had doubtless often to surrender to the dis- honest usurper. The account which Reaumur has given of the opera- tions of this class of bees diflers considerably from that which we have here detailed ; from the species being different, or from his bees not having been able to procure moist clay. On the contrary, sand was the chief material used by his 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 con- sequently to expend a much greater quantity of saliva, than our bees (Osmia bicornis) which worked with moist clay. Reaumur, indeed, ascertained that every individual grain of sand is moistened previous to its being joined to the pellet, in order to make it adhere more effectually. The tenacity of the mass is besides rendered stronger, he tells us, by adding a proportion of earth or garden mould. In this manner, a ball of mortar is formed, about the size of a small shot, and carried off to the nest. When the structure of this is examined, it has all the appear- ance externally of being composed of earth and small stones or gravel. The ancients, who were by no means accurate naturalists, having observed bees caiTying pellets of earth and small stones, supposed that they employed these, to add to their weight, in order to steady their flight when impeded by the wind. The nests thus constructed appear to have been MASON-BEES, 39 more durable edifices than those which have fallen under our observation; — for Reaumur 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 Reaumur and his friend Du Hamel, who studied the operations of these insects in concert. After taking a portion of sand from one part of the garden-walk, the bees usually took another portion from a spot almost twenty and sometimes a hundred paces off, though the sand, so far as could be judged by close examination, was precisely the same in the two places. We should be disposed to refer this more to the restless character of the insect, than to any difference in the sand. We have observed a wasp paring the outside of a plank, for materials to form its nest; and though the plank was as uniform in the qualities of its surface, nay, probably more so than the sand could be, the wasp fidgeted about, nibbling a fibre from one, and a fibre from another portion, till enough was procured for one load. In the same way, the Avhole tribe of wasps and bees flit restlessly from flower to flower, not unfrequently revisiting the same blossom, again and again, within a few seconds. It appears to us, indeed, to be far fi-om improbable, that this very rest- lessness and irritability may be one of the springs of their unceasing industry. By observing, with some care, the bees which we found digging the clay, we discovered one of them [Osmia bicornis) at work upon a nest, about a gun- shot from the bank. The place it had chosen was the inner wall of a coal-house, facmg the south-west, the brick-work of which was but roughly finished. In an upright interstice of half an inch in width, be- tween two of the bricks, we found the little architect 40 I.NSECT ARCHITECTURE. assiduously building its v*alls. The bricklayer's mortar had either partly fallen out, or been removed by the bee, who had commenced building at the lower end, and did not build downwards, as the social wasps construct their cells. The very different behaviour of the insect here, and at the quarry, struck us as not a little remarkable. When digging and preparing the clay, our approach, however near, produced no alarm; the work went on as if we had been at a distance; and though we were standing close to the hole, this did not scare away any of the bees upon their arrival to procure a fresh load. But if we stood near the nest, or even in the way by which the bee flew to it, she turned back or made a wide circuit immediately, as if afraid to betray the site of her domicile. We even observed her turning back, when v/e were so distant that it could not reasonably be supposed she was jealous of us; but probably she had detected some prowling insect- depredator, tracking her flight with designs upon her provision for her future progeny. We imagined we could perceive not a little art in her jealous caution, fir she Vvould alight on the tiles as if to rest herself ; and even when she had entered the coal-house, she did not go directly to her nest, but again rested on a shelf, and at other times pre- tended to examine several crevices in the wall, at some distance from the nest. But when there was nothing to alarm her, she flew directly to the spot, and began eagerly to add to the building. It is in instances such as these, which exhibit the adaptation of instmct to circumstances, that our reason finds the greatest difficulty, in explaining the governiig principle of the minds of the inferior ani- mals. The mason-bee malvcs her nest by an inva- riable rule; the model is in her mind, as it has been in the mind of her race from their first creation: they MASON-BEES. 4] have learnt nothing by experience. But the mode in which thej accomphsh this task varies according to the situations in which they are placed. They appear to have a ghmmering 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, within 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 l»atched. Contrary to what has been recorded by pre- ceding naturalists, with respect to other mason-bees, we found the cells in this instance quite parallel and perpendicular^ but it may also be remarked, that the 2 ' 3 Hi 1 fill 'ft 1 HI ^bW ^S| 1 ^Jp u I^BIU Cells of Mason-Bees, built, in the first and second figures, by Osmia bico7-nis between bricks, and in the third, liy Mcgachilt ia in the fluting ot" an old pilaster; about half the natural bee itself was a species altogether different from the one which we have described above as the Jlntho- phora retusa, and agreed with the figure of the one we caught quarrying the clay — (Osmia bicornis.) There was one circumstance attendmg the pro- ceedings of this mason-bee which struck us not a little, though we could not explain it to oiir own vol.. IV. 4* 42 INSECT ARCHITECTURE. satisfaction. Every time she left her nest for the pur- pose of procuring a fresh supply of materials, she paid a regular visit to the blossoms of a lilac tree which grevi^ near. Had these blossoms afforded a supply of pollen, with which she could have reple- nished 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 flov/ers. Besides, she did not return im; mediately 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 circum- stance:— she must either have applied to the lilac blossoms to obtain a refreshment of honey, or to pro- cure glutinous materials to mix with the clay. When employed upon the building itself, the bee exhibited the restless disposition peculiar to most hymenopterous* insects; for she did not go on with one particular portion of her wall, but ran about from place to place every time she came to work. At first, when we saw her running from the bottom to the top of her building, we naturally imagined that she went up for some of the bricklayer's mortar to mix with her own materials; but upon minutely examining the walls afterwards, no lime could be discovered in their structure, similar to that a\ hich 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 A\hich she forms her nest of garden mould moistened v/ith glu- ten, and afterwards closes the hole with the same material. * The fifth order of LinncBUs; insects with four transparent veined wings. MINING-EEES. 43 Mason-Bee and Nest— From. Reaumur. Mining-Bees. A very small sort of bees {Andrence.) , many of them not larger than a house-fly, dig in the ground tubular galleries little wider than the diameter of their own bodies. Samouelle says, that all of them seem to prefer a southern aspect; but we have found them in banks facing the east, and even the north. Immediately above the spot where we have described the mason-ijees quarrying the clay, we observed seve- ral holes, about the diameter of the stalk of a to- bacco-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 dov/n for six or eight inches, a very smooth circular gallery was found, terminating in a thimble-shaped horizontal chamber, almost at right angles to the entrance, and nearly twice as wide. In this chamber Cell of Minii\<;-Bee (Jndrena), — About half the natural sW.e. 44 INSECT ARCHITECTURE. there was a ball of bright yellow pollen, as round as a garden pea, and rather larger, upon which a small white grub was feeding; and to which the mother bee had been adding, as she had just entered a minute before with her thighs loaded with pollen. That it was not the male, the load of pollen determined; for the male has no apparatus for collecting or trans- porting it. The whole labour of digging the nest and providing food for the young is performed by the female. The females of the solitary bees have no assistance in their tasks. The males are idle; and the females are unprovided with labourers, such as the queens of the hive command. Reaumur mentions that the bees of this sort, whose operations he had observed, piled up at the entrance of their galleries the earth which they had scooped out from the interior; and when the grub was hatched, and properly provided with food, the earth was again employed to close up the passage, in order to prevent the intrusion of ants, ichneumon flies, or other de- predators. In those which we have observed, this was not the case; but every species differs from another in some little peculiarity, though they agree in the general principles of their operations. Chapter III, Carpenter-Bees ; Carpeuter-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 m stone. We have frequently witnessed the operations of these inge- nious little workers, who are particularly partial to posts, palings, and the wood-work of houses which has become soft by beginnmg to decay. Wood actually decayed, or affected by dry-rot, they seem to reject as unfit for their purposes; but they make no objec- tions to any hole previously drilled, provided it be not too large ; and, hke the mason-bees, they not unfrequently take possession of an old nest, a few repairs being all that in this case is necessary. When a new nest is to be constructed, the bee proceeds to chisel sufficient space for it out of the wood with her jaws. We say her, because the task in this histance, 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 giv- ing his assistance, and he seldom, if ever, approaches the neighbourhood. The female carpenter-bee has a task to perform no less arduous than the mason-bee; for though the wood may be tolerably soft, she can 46 INSECT ARCHITECTURE, only cut out a very small portion at a time. The suc- cessive 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 (Odijnerus), at page 25, we remarked the care with which she carried to a distance little frag- ments of brick, which she detached in the progress of excavation. We have recently watched a precisely similar procedure in the instance of a carpenter-bee forming a cell in a wooden post.* The only difference was, that the bee did not fly so far away with her frag- ments of wood as the wasp did; but she varied the direction of her flight every time: and we could ob- serve, that after dropping the chip of wood which she had carried off, she did not return in a direct line to her nest, but made a circuit of some extent before wheeling round to go back. On observing the proceedings of this carpenter-bee next day, we found her coming in with balls of pollen on her thighs; and on tracing her from the nest into the adjacent garden, we saw her visiting every flower which was likely to yield her a supply of pollen for her future progeny. This was not all: we subse- quently saw her taking the direction of the clay- quarry frequented by the mason-bees, as we have mentioned in page 35, where we recognized her loading herself with a pellet of clay, and carrying it into her cell in the wooden post. We observed her alternating this labour for several days, at one time carrying clay, and at another pollen; till at length she completed her task, and closed the entrance with a barricado 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. » J. R. CARPENTER-BEES. 47 Cells of Carpenter-Bees, excavated'in an old post.— In fig.A the cells contain the young grubs ; in fig. B the cells are empty. Bot6 figures are shown in section, and about half ihe natuial size. 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 chiselled by a joiner. There were five cells, arranged in a very singular manner — two being ahnost horizontal, two perpendi- cular, and one obUque. The depth to which the wood was excavated, in this instance, was considerably less than what we have observed in other species which dig perpendi- cular galleries several inches deep in posts and gar- den-seats ; and they are inferior in ingenuity to the carpentry of a bee described by Reaumur (Xijlocopa violacea), which has not been ascertained to be a native of Britain, though a single uidigenous species of the genus has been doubtingly mentioned, and is 48 INSECT ARCHITECTURE. figured, by Kirby, in his valuable ' Monographia. ' If it ever be found here, its large size and beautiful violet-coloured wings will render mistakes impossi- ble. The violet carpenter-bee usually selects an up- right piece of wood, into which she bores obhquely for about an inch ; and then, changing the direction, works perpendicularly, and parallel to the sides of the wood, for twelve or fifteen inches, and a 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 growth of her progeny, that each should be separated from the other, and be provided with adequate food. She knows, most exactly, the quantity of food which each grub will require, during its growth ; and she there- fore does not hesitate to cut it oif from any additional supply. In constructing her cells, she does not employ clay, like the bee which we have mentioned above, but the saw dust, if we may call it so, which she has collected in gnawing out the gallery. It would not, therefore, have suited her design to scatter this about, as our carpenter-bee did. The violet bee, on the contrary, collects her gnawings into a little store-heap for future use, at a short distance from her nest. She proceeds thus ; — at the bottom of her excavation she deposits an egg, and over it fills a space nearly an inch high with the pollen of flowers, made into a paste with honey. She then covers this over with a ceiling composed of cemented sawdust, which also serves for the floor of the ne.xt chamber above it. For thiis CARPENTER-BEES, 49 A. represents a part of an espalier prop, tunnelled in several places by the violet carpenter-bee: the stick is split, and shows the nests and passages by which they are approached. B, a portion of the prop, hall the natural size. C, a piece of thin stick, pierced by the carpenter-bee, and split, to show the nests. D. Perspec- tive view of one of the partitions. E, Carpenter-bee (Xylocopa tiiolacea). F, Teeth of the carpenter-bee, greatly magnified : «, the upper side ; b, lower side purpose, she cements round a wall a ring of wood chips, taken from her store heap ; and within this ring forms another, gradually contracting the diameter till she has constructed a circular plate, about the thick- ness of a crown-piece, and of considerable hardness. VOL. IV. 5 50 INSECT ARCHITECTURE, This plate of course exhibits concentric circles, some- what similar to the annual circles in the cross section of a tree. In the same manner she proceeds till she has completed ten or twelve cells ; and then she closes the main entrance with a barrier of similar materials. Let us compare the progress of this little joiner with a human artisan — one who has been long practiced 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 hfe, but it is then as complete and finished as if she had made a thousand. She has no pattern before her — but the Architect of all things has impressed a plan upon her mind, which she can reahze 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, Avith greater ease than the workman who bores into the earth for water, with his apparatus of augurs adapted to every soil. Her tunnel is clean and regular ; she leaves no chips at the bottom, for she is provident of her materials. Further, she has an exquisite piece of joinery to per- form, when her ruder labour is accomplished. The patient bee works her rings from the circumference to the centre, and she produces a shelf, united with such care with her natural glue, that a number of fragments are as sohd as one piece. The violet carpenter-bee, as may be expected, oc- cupies several weeks in these complicated labours ; and during that period she is gradually depositing her eggs, each of which is successively to become a grub, a pupa, and a perfect bee. It is obvious, therefore, as she does not lay all her eggs in the same place — as each is separated from the other by a laborious process — that the egg which is first laid will be the earliest hatched ; and that the first perfect CARPENTER-BEES. 51 insect, being older than its fellows in the same tun- nel, 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 saw- dust in the interior. Reaumur observed these holes, in several cases; and he further noticed another ex- ternal opening opposite to the middle cell, which he supposed was formed, in the first instance, to shorten the distance for the removal of the fragments of wood in the lower half of the building. That bees of similar habits, if not the same spe- cies 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 old elder branch, in which they were placed lengthwise, one after an- other, with a thin boundary between each. As he does not, however, tell us that he was acquainted with the insect which constructed these, it might as probably be allied to the Ceratina albilabris, of which Spinola has given so interesting an account in the ' Aimales du MusLum 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 perfo- rated, and that the insect was in the very act of exca- vating a nidus for her eggs. He forthwith gathered a bundle of branches, both of the bramble and the wild-rose, similarly perforated, and took them home to examine them at leisure. Upon inspection, he 52 INSECT ARCHITECTURE. found that the nests were furnished, like those of the same tribe, with balls of pollen kneaded with honey, as a provision for the grubs. The female ceratina selects a branch of the bramble or wild-rose which has been accidentally broken, and digs into the pith only, leaving the wood and bark untouched. Her mandibles, indeed, are not adapted for gnawing wood; and, accordingly, he found in- stances in which she could not finish a nest in branches of the wUd-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 sepa- rated by partitions formed of the gnawings of the pith, cemented by honey, or some similar glutinous fluid, much in the same manner with the xylocopa violacea, which we have already described. Carpenter- Wasps. As there are mason-wasps similar in economy to mason-bees, so are there solitary carpenter-wasps which dig galleries in timber, and partition them out into several cells by means of the gnawings of the wood which they have detached. This sort of wasp is of the genus Eumenes. The wood se- lected is generally such as is soft, or in a state of decay; and the hole which is dug in it is much less neat and regular than that of the carpenter-bees, while the division of the cbambers is nothing more than the rubbish produced during the excavation. The provision which is made tor the grub consists of flies or gnats piled into the chamber, but without the nice order remarkable in the spiral columns of green caterpillars provided by the mason-wasp (Odinerus murarius). The most remarkable cir- cumstance is, that in some of the species, when the CARPENTER-WASPS, .53 A B represent sections of old wooden posts, with the cells of the carpenter- wasp. In fig. A the young grubs are shewn feeding on the insects placed tliere for their support Ijy the parent wasp. The cells in fig. E contains cocoons. (J. carpenter-wasp, natural size, n, cocoon of a carpenter-wasp, composed of sawdust and wings of insects. grub is about to go into the pupa state, it spins a case (a cocoon), into which it interweaves the wings of the flies whose bodies it has previously devoured. In other species, the gnawings of the wood are em- ployed in a similar manner. Upholsterer-Bees. In another part of this volume we shall see how certain caterpillars construct abodes for themselves, by cutting off portions of the leaves or bark of plants, and uniting them by means of silk into a uniform and compact texture; but this scarcely ap- pears so wonderful as the prospective labours of some species of bees for the lodgment of their pro- geny. We allude to the solitary bees, known by the name of the leaf-cutting bees, but which may be de- noininated more generally upholsterer-hees^ as there are some of them which use other materials besides leaves. VOL. IV. 5* 54 INSECT ARCHITECTURE. One species of our little upholsterers has been called the poppy-bee (Osmia j}apaveris, Latr.), from its selecting the scarlet petals of the poppy as tapestry for its cells. Kirby and Spence express their doubts whether it is indigenous to this coun- try: we are almost certain that we have seen the nests in Scotland.* At Largs, in Ayrshire, a beau- tiful sea-bathing village on the Frith of Clyde, in July, 1814, we found in a foot-path a great num- ber of the cylindrical perforations of the poppy- bee. Reaumur remarked that the cells of this bee which he found at Bercy, were situated in a nor- thern exposure, contrary to what he had remarked in the mason-bee, which prefers the south. The cells at Largs, however, were on an elevated bank, facing the south, near Sir Thomas Brisbane's ob- servatory. 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 car- penter-bees make choice of a similar situation. In one instance, we found carpenter-bees working in- differently on the north-east and south-west side of the same post. As we did not perceive any heaps of earth near the holes at Largs, we concluded that it must either have been carried off piecemeal when they were dug, or that they were old holes re-occupied, — (a circumstance common with bees), and that the rub- bish had been trodden down by passengers. Reau- mur, who so minutely describes the subsequent opera- tions of the bee, says nothing respecting its excava- tions. One of these holes is about three inches deep, gradually widening as it descends, till it assumes the form of a small Florence flask. The interior of this is rendered smooth, uniform, and polished, in order * J. R. UPHOLSTERER-BEES. 55 to adapt it to the tapestry with which it is in- tended to be hung, and which is the next step in the process. The material used for tapestry by the msect uphol- sterer is supplied by the petals* of the scarlet field- poppy, from which she successively cuts off small pieces of an oval shape, seizes them between her legs, and conveys them to the nest. She begins her work at the bottom, which she overlays with three or four leaves in thickness, and the sides have never less than two. When she finds that the piece she has brought is too large to fit the place intended, she cuts off what is superfluous, and carries away the shreds. By cut- ting 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 cham- ber all round with this splendid scarlet tapestry, of which she is not sparing, but extends it even be- yond 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 m with earth; but Latreille says, he has observed more than one cell constructed in a single excavation. This may account for Reau- mur'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 * Petal is the term employed by botanists to denote the leaf, or division of the coloured portion of a flower. 56 INSECT ARCHITECTURE, select the brilliant petals of the poppy from their co- lour, or from any other quality they may possess, of softness or of warmth, for instance. Reaumur 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 pos- sess a feeling of the beautiful in colour, and may look with complacency upon the delicate hang- ings of the apartment which she destines for her offspring. Why should not an insect be supposed to have a glimmering of the value of ornament ? How can we pronounce, from our limited notion of the mode in which the inferior animals think and act, that their gratifications are wholly bounded by the positive utility of the objects which sur- round them? Wliy does a dog howl at the sound of a bugle, but because it offends his organs of hear- ing.?— and why, therefore, may not a bee feel glad- ness in the brilliant hues of her scarlet drapery, be- cause they are grateful to her organs of sight ? AH these little creatures work, i)robably, with more neat- ness and finish than is absolutely essential for com- fort; and this circumstance alone would imply that they have something of taste to exliibit, which pro- duces to them a pleasurable emotion. The tapestry-bee is, however, content mth orna- menting the interior only of the nest which she forms for her progeny. She does not misplace her embel- lishments with the error of some human artists. She desires security as well as elegance; and, therefore, she leaves no external traces of her operations. Her's is not a mansion rich with columns and friezes with- out, but cold and unfurnished within, like the deso- late palaces of Venice. She covers her tapestry quite round with the common earth; and leaves her eggs enclosed in their poppy-case with a certainty UPHOLSTERER-BEES. 57 that the outward shew of her labours will attract no plunderer. The poppy-bee may be known by its being rather more than a third of an inch long, of a black colour, studded on the head and back with reddish grey hairs; the belly being grey and silky, and the rings margined with grey above, the second and third having an impressed transversal line. A species of solitary bee (Anthidium manicatum, Fabricius), by no means uncommon with us, forms a nest of a peculiarly interesting structure. Kirby and Spense say, that it does not excavate holes, but makes choice of the cavities of old trees, key-holes, and si- milar 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 se- lected a place suitably sheltered from the weather, and from the intrusion of depredators, proceeds to form her nest, the exterior walls of which she forms of the wool of pubescent plants, such as rose-cam- pion {Lychnis coronaria), the quince [Pyrus cydo- nia), cats-ears {Stachys lanata), kc. " It is very pleasant," says Mr White of Selborne, " to see with what address this insect strips oif the down, running from the top to the bottom of the branch, and shaving it bare with all the dexterity of a hoop shaver. When it has got a vast bundle, almost as large as itself, it flies away, holding it secure between its chin and its fore-legs."* The manner in which the cells of the nest are *Naturalist's Calender, p. 109. 58 INSECT ARCHITECTURE. 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 Spense, on the other hand, tell us, that " the parent bee, ujter 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 Romford's expe- riments, 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 envelopes them with a warm coating of down, impervious to every change of temperature." " From later observations," however, they are " inclined to think that these cells may possibly, as in the case of the humble-bee, be in fact formed by the larva pre- viously to becoming a pupa, after having eaten the provision of pollen and honey with which the parent bee had surrounded it. The vermicular shape, how- ever, of the masses with which the cases are sur- rounded, does not seem easily reconcileable with this supposition, unless they are considered as the excre- ment 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 first is incorrect, as it is con- trary to the regular procedure of insects, to begin with the interior part of any structure, and work out- wards. We should imagine, then, that the down is first spread out into tlie form required, and afterwards plastered on the inside to keep it in form, when pro- * Introduction to Entomology, vol. i. p. 435, 5th edit. UPHOLSTERER-BEES. 59 bably 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. 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 sLx yellow or white spots along each side of the rings, very hke the rose- leaf cutter, and having the belly covered with yellow- ish brown hair, and the legs fringed with long hairs of a rather lighter colour. A common bee belonging to the family of uphol- sterers is called the rose-leaf cutter {Megachile cen- tuncularis, Latr.) The singularly ingenious habits of this bee have long attracted the attention of naturalists, but the most interesting description is given by Reaumur. So extraordinary does the construction of their nests appear, that a French gardener having dug up some, and believing them to be the work of a magician, who had placed them in his garden with evil intent, sent them to Paris to his master, for ad- vice as to what should be done by way of exorcism. On applying to the Abbe NoUet, the owner of the garden was soon persuaded that the nests in ques- tion were the work of insects; and M. Reaumur, to whom they were subsequently sent, found them to be the nests of one of the upholsterer-bees, and pro- bably of the rose-leaf cutter, though the nests in ques- tion 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,) 60 INSECT ARCHITECTURE. from six to ten inches deep, and does not throw the earth dug out from it into a heap, Hke the an- dreniBe.* 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 suc- cession. It is interesting to observe the manner in which this bee procures the materials for forming the tapes- try 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 ser- rated margins, such as the birch, the perennial mer- cury i^Mercurialis 2:>ere7inis) , mountain ash, &c. She places herself upon the outer edge of the leaf which she has selected, so that its margin may pass between her legs. Turning her head towards the point, she commences near the footstalk, and with her mandi- bles cuts out a circular piece with as much expedi- tion as we could do with a [)air of scissors, and with more accuracy and neatness than could easily be done by us. As she proceeds, she keeps the cut portion be- tween her legs so as not to impede her progress; and using her body for a trammel, as a carpenter would say, she cuts in a regular curved line. As she sup- ports herself during the operation upon the portion of the leaf which she is detaching, it must be ob- vious, when it is nearly cut off, that the weight of her body might tear it away, so as to injure the accu- racy of its curvilineal shape. To prevent any acci- dent of this kind, as soon as she suspects that her weight might tear it, she poises herself on her wings, till she has completed the incision. It has been said, by naturalists, that this manoeuvre of poising * See p. 43. UPHOLSTERER-BEES. 61 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 ex- planation is probably the true one. Rose leaf-cutter bees, and nest lined with rose-leaves. With the piece which she has thus cut out, held in a bent position perpendicular to her body, she flies off to her nest, and fits it into the interior with the ut- most neatness and ingenuity; and, without employing any paste or glue ; the trusts, as Reaumur ascertained, to the spring the leaf takes, in trying to retain it in its position. It requires from nine to twelve pieces of leaf to form one cell, as they are not always of pre VOL. IV. 6 62 INSECT ARCHITECTURE. cisely the same thickness. The interior surface of each cell consists of three pieces of leaf, of equal size, narrow at one end, but gradually Avidening 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 inner- most. Like most insects, she builds from the inte- rior, beginning with a layer of tapestry, which is composed of three or four oval pieces, larger in dimensions than the rest, adding a second and a third layer proportionately smaller. In forming these, she is careful not to place a joining opposite to a joining, but witli all the skill of a consummate ar- tificer, 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 fifth layer of leaves, taking care to bend the leaves at the narrow extremity or closed end of the cell, so as to bring them into a convex shape. When she has in this manner completed a cell, her next business is to replenish it with a store of honey and pollen, which, being chiefly collected from thistles, forms a beautiful rose-coloured conserve. In this she deposites a single egg, and then covers in the opening with three pieces of leaf, so exactly circular, that a pair of compasses could not define their mar- gin with more accuracy. In this manner the indus- trious and ingenious upholsterer proceeds till the whole gallery is filled, the convex extremity of the one fitting into the open end of the next, and serving both as a basis and as the means of strengthening it. If, by any accident, the labour of these insects is interrupted or the edifice deranged, they exhibit astonishing perseverance in setting it again to lights. UPHOLSTERER-BEES. 63 Insects, indeed, are not easily forced to abandon any work which they may have begun. The monkish legends tell us that St Francis Xavier, walking one day in a garden, and seeing an insect of the Mantis genus, moving along in its solemn way, holding up its two fore legs as in the act of devotion, desired it to sing the praises of God. The legend adds that the saint immediately heard the insect carol a fine canticle with a loud emphasis. We want no miraculous voice to record the wonders of the Almighty hand, when we regard the insect world. The little rose-leaf cutter, pursuing her work vdth the nicest mathematical art — using no artificial instruments to form her ovals and her circles — know- ing 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 pro portioned her knowledge to her necessities. Chapter IV. Carder-Bees ; Humble-Eees ; Social-Wasps. The bees and wasps, whose ingenious architecture we have ah-eady examined, are solitary in their la- bours. Those we are about to describe hve in so- ciety. 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 intelli- gence. 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 Carder-Bees. The nests of the bees which Reaumur denomi- nates carders (Bomhus muscorum, Latr.), are by no means uncommon, and are well worth the study of the naturalist. During the hay harvest, they are fre- quently met with by mowers in the open fields and meadows; but they may sometimes be discovered in hedge-banks, the borders of copses, or among moss- grown stones. The description of the mode of build- ing adopted by this bee has been copied by most of our writers on insects from Reaumur; though he is not a little severe on those who write, without having ever had a single nest m their possession. We have been able to avoid such a reproach ; for we have now before CARDER-BEES. 65 US a very complete nest of carder-bees, which differs fi-om those described by R aumur, in being made, not of moss, but withered grass. With this exception, we find that his account agrees accurately with our own observation.* The carder-bees select for their nest a shallow ex- cavation about half a foot in diameter; but when they cannot find one to suit their purpose, they under- take the Herculean task of digging one themselves. They cover this hollow with a dome of moss — some- times, as we have ascertained, of withered grass. They make use, indeed, of whatever materials may be within their reach; for they do not attempt to bring any thing from a distance, not even when they are deprived of the greater portion by an experimental naturalist. Their only method of transporting ma- terials to the building is by pushing them along the ground — the bee, for that purpose, working back- wards, with its head turned from the nest. If there is only one bee engaged in this labour, as usually happens in the early spring, when a nest is founded by a solitary female who has outlived the winter, she transports her little bundles of moss or grass by suc- cessive backward pushes, till she gets them home. In the latter part of the season, when the hive is populous and can afford more hands, there is an in- genious division of this labour. A file of bees, to the number sometimes of half a dozen, is established, from the nest to the moss or grass which they intend to use, the heads of all the file of bees being turned from the nest and towards the material. The last bee of the file lays hold of some of the moss with her mandibles, disentangles it from the rest, and having carded it with her fore-legs into a sort of felt or small bundle, she pushes it under her body to the *J. R. VOL. IV. 6* 66 INSECT ARCHITECTURE. next bee, who passes it in the same manner to the j next, and so on till it is brought to the border of the 1 nest, — in the same way as we sometimes see sugar- : loaves conveyed from a cart to a warehouse, by a file .. of porters throwing them from one to another. ? Fig. A represents two carder-bees heckling moss for their nesLs. B, exterior view of tlie nest of the carder-bee. 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 CARDER-BEES. 67 preventing high winds from destroying it. Before this finishing is given to the nest, we have re- marked, that on a fine sunshiny day, the upper portion of the dome was opened to the extent of more than an inch, in order, we suppose, to forward the hatching of the eggs in the interior; but on the approach of night this was carefully covered in again. It was remarkable that the opening which we have just mentioned was never used by the bees for either their entrance or their exit from the nest, though they were all at work there, and, of course would have found it the readiest and easiest passage. But they invariably made their exit and their entrance through the covert-way or gallery which opens at the bottom of the nest, and in some nests, is about a foot long and half an inch wide. This is, no doubt, intended for concealment, fi"om field-mice, polecats, wasps, and other depredators. On removing a portion of the dome and bringing the interior of the structure into view, we find little of the architectural regularity so conspicuous in the combs of a common bee-hive: instead of this sym- metry, there are only a iJew egg-shaped, dark-coloured cells, placed somewhat irregularly, but approaching more to the horizontal than to the vertical position, and connected together with small amorphus* columns of brown wax. Sometimes there are two or three of these oval cells placed one above another, without anything to unite them. These cells are not, however, the workmanship of the old bees, but of their young grubs, who spin them when they are about to change into nymphs. But, from these cases, when they are spun, the en- closed insects have no means of escaping, and they depend for their liberation on the old bees gnawing * Shapeless. 88 INSECT ARCHITECTUKE. off the covering, as is done also by ants in the same circumstances. The instinct with which they knoAV the precise time when it is proper to do this is truly wonderful. It is no less so, that these cocoons are by no means useless when thus un- tenanted, for they subsequently serve for honey-pots, and are indeed the only store-cells in the nest. For this pur^iose the edge of the cell is repaired and strengthened with a ring of wax. Breeding Cells. The true breeding-cells are contained in several amorphus masses of brown-coloured wax, varying in dimensions, but of a somewhat flat and globular shape. On opening any of these, a number of eggs or grubs are found, on whose account the mother bee has collected the masses of wax, which also con- tain a supply of pollen moistened with honey, for their subsistence. The number of eggs or grubs found in one sphe- roid 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 lemales 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 livtt in harmony together. CARDER-BEES. 69 Interior views of Carder-bee's Nest. The carder-bees may be easily distinguished from their congeners (of the same genus), by being not unlike the colour of the withered moss with which they build their nests, having the fore part of their back a dull orange, and hinder part ringed with dif- ferent shades of greyish yellow. They are not so large as the common humble-bee {Bombus terreslris, Latr). but rather shorter and thicker in the body than the common hive-bee (Jipis meUifica.) 70 insect architecture. Lapidary-Bees. A bee still more common, perhaps, than the carder, is the orange-tailed bee, or lapidary (Bombiis lapi- daria), 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 vin- dictive. About two years ago, we discovered a nest of the.se bees at Compton-Basset, in Wiltshire, in the centre of a heap of limestone rubbish; but owing to the brisk defensive warfare of their legionaries, we could not obtain a view of the interior. It was not even safe to approach within many yards of the place, and we do not exaggerate when we say that several of them pursued us most pertinaciously about a quarter of a mile.* Humble Bees. The common humble-bee (Bombvs terreslris) is precisely similar in its economy to the two preceding species, with this difference, that it forms its nest underground like the common wasp, in an excavated chaml)cr, 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 besi(]o the vault of the excavation and patches of coarse wax similar to that of the carder-bee. » .1. 1!. social-wasps. . 71 Social Wasps. The nest of the common wasp ( Vespa vulgaris) attracts more or less the attention of every body ; but its interior architecture is not so well known as it deserves to be, for its singular ingenuity, in which it rivals even -that of the hive-bee {Jlpis mellijica). In their general economy, the social, or republican wasps, closely resemble the humble-bee (Bombus), every colony being founded by a single female who has survived the winter, to the rigours of which all her summer associates of males and working wasps uniformily fall victims. Nay, out of three hundred females which may be found in one vespiary, or wasp's nest, towards the close of autumn, scarcely ten or a dozen survive till the ensuing spring, at which season they awake from their laybernal lethargy, and begin with ardour the labours of colonization. It may be interesting to follow one of these mo- ther 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, al- ways ready to execute her commands, and to do her homage. The mother wasp, on the contrary, is at first alone, and is obliged to perform every species of drudgery herself Her first care, after being roused to activity by the returning warmth of the season, is to discover a place suitable for her intended colony; and, ac- cordingly, in the spring, waspS may be seen prying into every hole of a hedge bank, particularly where field-mice have burrowed. Some authors report that she is partial to the forsaken galleries of the mole, but this does not accord with our observations, as we have never met with a single vespiary in any situation likely to have been frequented by moles 72 INSECT ARCHITECTURE. But though Avc cannot assert the fact, we thinlt it highly probable that the deserted nest of the field- mouse, which is not uncommon in iiedge banks, may be sometimes appropriated by a mother wasp as an excavation convenient for her purpose. Yet, if she does make choice of the burrow of a field-mouse, it requires to be afterwards considerably enlarged in the interior chamber, and the entrance gallery very much narrowed. The desire of the wasp to save herself the labour of excavation, by forming her nest where other ani- mals have burrowed, is not without a parallel in the actions of quadrupeds, and even of birds. In the splendid continuation of Wilson's American Orni- thology, by Charles L. Bonaparte (whose scientific pursuits have thrown around that name a beneficent lustre, pleasingly contrasted with his uncle's glory), there is an interesting example of this instinctive adoption of the labours of otliers. " In the trans- Mississippian territories of the United States, the burrowing-owl resides exclusively in the villages of the marmot, or prairie dog, whose excavations are so commodious, as to render it unnecessary that the owl shculd dig for himself, as he is said to do where no burrowing animals exist.* The villages of the prairie dog are very nume- rous and variable in their extent, — sometimes covering only a few acres, and at others spreading over the surface of the country for miles together. They are composed of slightly elevated mounds, having the tbrm of a truncated cone, about two feet in width at the base, and seldom rising as high as eighteen inches from the surface of the soil. The * The ow] observed by Vj^'illol in St Doiuiiigo digs itself a burrow two feet in depth, at the bottom of which it deposits its eggs upon a bed of luoss. SOCIAL-WASPS. 73 entrar.ce is placed either at the top or on the side, and the Avhole 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 ter- minates in an apartment, within which the industrious prarie-dog constructs, on the approach of cold weather, a comfortable cell lor his winter's sleep. The cell, Avhich is composed of fine dry grass, is globular in form, with an opening at top, capable of admitting the finger ; and the whole is so firmly compacted, that it might, Mdthout injury, be rolled over the floor."* In case of need the wasp is abundantly fur- nished by nature with instruments for excavating a burrow out of the solid ground; as she no doubt most commonly does, — digging the earth with her strong mandibles, and carrying it off or pushing it out as she proceeds. The entrance-gallery is about an inch or less in diameter, and usually runs in a winding or zigzag direction, from one to two feet in depth. In the chamber to wJiich 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 Avere long a matter of conjecture to scientific inquirers ; for the bluish-grey papery substance of the- whole struc- ture has no resemblance to any sort of wax employed by bees for a similar purpose. Now that the discovery has been made, we can with difficulty bring our^^ selves to believe that a naturalist so acute and inde- fatigable as ]M. Reaumur should have, for twenty years, as he tells us, endeavoured, without success, * American Ornithology, by Ciiarles Lucien Bonaparte. A^ol. i. p. 69. VOL. IV. 7 74 INSECT ARCHITECTURE. to find out the secret. At length, however, his per- severance 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 procuruig znaterials for building. He saw her detach from the wood a bundle of fibres about a tenth of an inch in length, and finer than a hair ; and as she did not swallow these, but gathered them into a mass with her feet, he could not doubt that his first idea was correct. In a short time she shifted to another part of the window-frame, carrying with her the fibres she had collected, and to which she continued to add, when he caught her, in order to examine the nature of her bundle"; and he found that it was not yet moistened nor rolled into a ball, as is always done before em- ploying 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 remark- able that it bore no resemblance to wood gnawed by other insects, such as the goat-moth caterpillar, which is granular like sawdust. This would not have suited the design of the wasp, who was well aware that fibres of some length form a stronger texture. He even discovered, that before detaching the fibres, she bruised them {les charpissoit) into a sort of lint (charpie) with her mandibles. All this the careful naturalist imitated by bruising and paring the same wood of the window-sash with his pen-knife, till he succeeded in making a little bundle of fibres scarcely to be distinguished from that collected by the wasp. We have ourselves frequently seen wasps em- ployed in procuring their materials in this manner, and have always observed tluit they shitl from one part to another more than once in preparing a single load, — a circumstance whidi we ascribe entirely to SOCIAL-WASPS. to the restless temper peculiar to the whole order of hymenopterous insects. Reaumur found that the wood which they preferred was such as had been long exposed to the weather, and is old and dry. White of Selborne, and Kirby and Spence, on the contrary, maintain that wasps obtain their paper from sound timber, hornets only from that which is decayed.* Our own observations, however, confirm the statement of Reaumur, with respect to wasps, as, in every instance which has fallen under our notice, the wood selected was very much weathered ; and in one case an old oak post in a garden at Lee, in Kent, half destroyed by dry-rot, was seemingly the resort of all the wasps in the vicinity. In another case, the deal bond in a biick wall, which had been built thirty years, is at this moment (June, 1829) literally striped with the gnawings of wasps, which we have watched at the work for hours together. | The bundles of ligneous fibres thus detached, are moistened, before being used, with a glutinous liquid, which causes them to adhere together, and are then kneaded into a sort of paste, or pajiicr macJiL Having prepared some of this material, the mother wasp begins first to line with it the roof of her chamber, for wasps always build downwards. The round ball of fibres which she has previously kneaded up with glue, she now forms into a leaf, walking backwards, and spreading it out with her mandibles, her tongue, and her feet, till it is as thin almost as tissue paper. One sheet, however, of such paper as this would foi-m but a fragile ceiling, quite insufficient to pre- vent the earth from falling down into the nest. The wasp, accordingly, is not satisfied with her work * Reaumur, vol. vi. bottom of page 182 ; Hist, of Selb. i/ 22S ; and Introd. to Entomol. i. 504, 5th edition. t J. R. 1G INSECT ARCHITECTURE. till she has spread fifteen or sixteen layers one above the other, rendering the wall altogether nearly two inches thick. The several layers are not placed m contact like the layers of a piece of pasteboard, but with small mtervals or open spaces between, ap- pearing somewhat like a grotto built with bivalve shells, particularly when looked at on the outside. This is probably caused by the insect working in a curvilineal manner. Section of tht Social-Wa'ip's Ticst.—a a, the external ^Yall ; h, cc, five small terracps of cells for the neuter wasps; d d, e e , three rows of larger cells lor the ina!c5 aiul females. Having finished the ceiling, she next begins to build the first terrace of her citv, which, uM(k>r its SOCIAL-WASPS. 77 protection, she suspends horizontally, and not like the combs in a bee-hive, in a perpendicular position. The suspension of which we speak is also light and elegant, compared with the more heavy union of the hive-bees' combs. It is in fact a hanging floor, immoveably secured by rods of similar materials with the roof, but rather stronger. From twelve to thirty of these rods, about an inch or less in length, and a quarter of an inch in diameter, arc constructed A, represents one of ihe roih fiom Kliich the ten pcnded B, a portion of the tsctemal cri t are sus- for the suspension of the terrace. They are elegant in form, being made gradually narrower towards the middle, and widening at each end, in order, no doubt, to render their hold the stronger. The terrace itself is circular, and composed of an immense number of cells, formed of the paper al- ready described, and of almost the same size and form as those of a honey-comb, each being a perfect hexagon, mathematically exact, and every hair's breadth of the space completely filled. These cells, however, are never used as honey-pots by wasps, as they are by bees; for wasps make no honey, and the cells are wholly appropriated to the rearing of their young. Like other hymenopterous insects, the grubs are placed with their heads downwards; and tlie openings of the cells are also downwards: whil© vou IV, 7* 78 IKSECT ARCHITECTURE. their united bottoms form a neariy uniform level upon which the inhabitants of the nest may walk. We have seen, in describing the economy of the carder-bee, that when a young bee had escaped from its cradle-cell, and so rendered it empty, that cell was subsequently appropriated to the storing of honey. But in the case of wasps, a cell thus evacuated is immediately cleaned out and repaired for the recep- tion of another grub — an egg being laid in it by a female wasp as soon as it is ready. When the foundress wasp has completed a certain number of cells, and deposited eggs in them, she soon intermits her building operations, in order to procure food for the young grubs, 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 foundress by side walls, and forming another plat- form of cells, suspended to the first by columns, as that had been suspended to the ceiling. In this manner several platforms of combs arc constructed, the outer walls being extended at the same time; and, by the end of the summer, there is fenerally from twelve to fifteen platforms of cells. iach contains about 1060 cells — forty-nine being contained in an inch and a half square, and, of course, making the enornjous number of about 16,000 cells in one colony. R aumur, upon these data, calculates that one vespiary may produce every year more than 30,000 wasps, reckoning only 10,000 cells, and each serving successively for the cradle of three genera- tions. But, although the whole structure is built at the expense of so much labour and ingenuity, it has scarcely been finished bclbre the winter sots in, when it becomes nearly useless, and serves only for the abode of a few benumbed females, who abandon it on the approach of spring, and never return; for SOCIAL-WASPS. 79 wasps do not, like mason-bees, ever make use of the same nest for more than one season. Both Reaumur and the younger Huber studied the proceedings of the common wasp in the manner which has been so successful in observing bees — by means of glazed hives, and other contrivances. In this, these naturalists were greatly aided by the ex- treme affection of wasps for their young; for though their nest is carried off, or even cut in various direc- tions, and ex])osed to the light, they never desert it, nor relax their attention to their progeny. When a wasp's nest is removed from its natural situation, and covered with a glass hive, the first operation of the inhabitants is to repair the injuries it has suffered. They carry off with surprising activity all the earth or other matters which have fallen by accident into the nest; and when they have got it thoroughly cleared of everything extraneous, they begin to se- cure it from further derangement, by fixing it to the glass with papyraceous columns, similar to those which we have already described. The breaches which the nest may have suffered are then repaired, and the thickness of the walls is augmented, with the design, perhaps, for more effectually excluding the light. The nest of the hornet is nearly the same in struc- ture with that of the wasp; but the materials are considerably coarser, and the columns to which the platforms of cells are suspended are larger and stronger, the middle one being twice as thick as any of the others. The hornet, also, does not build under ground, but in the cavities of trees, or in the thatch or under the eaves of barns. Reaumur once found upon a wall a hornet's nest which had not been long begun, and had it transferred to the outside of his study window; but in consequence, 80 INSECT ARCHITECTURE. as he imagined, of the absence of the foundress hornet at the time it was removed, he could not get the other five hornets, of which the colony consisted, either to add to the building or repair the damages which it had sustained. Horncl^s nest in its first stage. M. Reaumur differs from our English naturalists, White, Kirby, and Spence, with respect to the ma- terials employed by the hornet 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 con- structing the suspensory columns of the platforms, a paste is prepared little inferior to that made by wasps. SOCIAL-WASPS. 81 of the above statements is correct, as we have only once seen a hornet procuring materials, at Compton- Basset, in Wiltshire ; and in that case it gnawed the inner bark of an elm which had been felled for seve- ral months, and was, consequently, dry and tough. Such materials as this would account for the common yellowish-brown colour of a hornet's nest.* When hornets make choice of a tree for their do- micile, they select one which is in a state of decay, and already partly hollowed : but they possess the means, in their sharp and strong mandibles, of ex- tending 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 dig- ging a gallery, sufficient for the passage of the largest hornet in the nest, through the hving and undecayed portion of the tree. As this is perforated in a wind- ing direction, it is no doubt intended for the purpose of protecting the nest from the intrusion of depre- dators, who could more easily effect an entrance if there were not such a tortuous way to pass through. One of the most remarkable of our native social- wasps is the Vespa britannicu, or tree-wasp, which is not uncommon 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 (Vespa vulgaris), or in the hollows of trees like the hornet (Vespa 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, *J. R 82 INSECT ARHITECTURE. and at Wemyss Bay, in Renfrewshire. The tree which the Britannic wasp prefers is the silver fir, whose broad flat branch serves as a protection to the suspended nest both from the sun and the rain. The materials and structure are nearly the same as those employed by the common wasp, and which we have already described.* A singular nest of a species of wasp is figured by Reaumur, but is apparently rare in this country, as Kirby and Spence mention only a single nest of similar construction, found in a 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-expanded Pro\ance rose. The British specimen mentioned by Kirby and Spence had only one platform of cells; Reaumur's 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 SOCIAL-WASPS. 83 nest was not much larger than a rose, and was com- posed of paper exactly similar to that employed by the common ground-wasp. There is another species of social-wasp (Epipone nidulans, Latr.) meriting attention from the singu- lar construction of 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 found a nest of this description attached to the stem of a nettle. Reaumur says they are sometimes attached to the branch of a thorn or other shrub, or to stalks of grass; — pecuHarities which prove that there are several species of these wasps. The most remarkable circumstance in the arclii- Wasp^s Cells attached to ahranch. 84 INSECT ARCHITECTURE. tecture 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 east, and conse- quently is less exposed to rains, which most fre- quently 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 moisture from soaking into the texture of the wasp's paper. The laying on this varnish, indeed, forms a considerable portion of the labour of the colony, and individuals may be seen employed for hours together spreading it on with their tongues. Few circumstances are more striking with regard to insects, as Kirby and Spence justly remark, than the great and incessant labour which maternal affection for their progeny^ leads them to undergo. Some of these exertions are so disproportionate 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 un- remittingly 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 ; and no sooner is this finished, than it will set about repeating the pro- cess, and before it dies, wUl have completed five or six similar cells, or even more. We shall have occasion more particulaily to dwell SOCIAL-WASPS. 85 upon the geometrical arrangement of the cells, both of the wasp and the social bee, in our description of those interesting operations, which have long at- tracted the notice, and commanded the admiration, of mathematicians and naturalists. A tew observa- tions may here be properly bestowed upon the ma" terial with wliich the wasp-family construct the in- terior of their nests. The wasp is a paper-maker, and a most perfect J and intelligent one. While mankind were ari'iving, by slow degrees, at the art of fabricating this valu- able 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 machineiy. While some nations carved their records on wood, and stone, and brass, and leaden tablets, — others, more advanced, wrote with a style on wax, — others employed the inner bark of trees, and others the skins of animals rudely prepared, — the wasp was manufacturing a firm and durable paper. Even when the papyrus was rendered more fit, by a process of art, for the transmission of ideas m writing, the wasp was a better artisan than the Egyptians; for the early attempts at paper- making were so rude, that the substance produced was almost 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 knew how to reduce vegetable fibres to a pulp, and then unite them by a size or glue, spread- ing 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 paper; she em- ploys other vegetable matters, converting them intq 86 INSECT ARCHITECTURE. a proper consistency by her assiduous exertions. In some respects she is more skihlil even than oui paper-makers, for she takes care to retam her fibres of sufficient length, by which she renders her paper as strong as she requires. Many manufacturers oi the present day cut their material into small bits, and thus pi-oduce a rotten article. One great distinction between good and bad paper is its toughness; and this indifference is invariably produced by the fibre of which it is composed being long, and therefore tough ; or shortj 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 tune to time, lose their excellence in particular arts, and they are slow in finding out real improve- ments. Such improvements are often the effect of ac- cident. 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 ibrni a roll large enough to extend round the globe, if such a length were de- sirable. The inventors of this machinery, JMessrs. Fourdrinier, it is said, spent fhe enormous sum of 40,000/. in vain attempts to render the machine capable of determining with precision the width of the roll; and, at last, accomplished their object, at the suggestion of a bystander, by a strap re- volving upon an axis, at a cost of three shillings and sixpence. Such is the difi'erence between the workings of human knowledge and experience, and those of animal instinct. We |)rocecd slowly and in the dark — but our course is not bounded by a nar- row Hue, for it seems difficult to say what is the per- SOCIAL-WASPS. 87 fection of aay art; animals go clearly to a given point — but they can go no further. We may, how- ever, learn something fiom 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 paper. We are still behind in our arts and sciences, because we have not always been observers. If we had watched the operations of bi- sects, and the structure of animals in general, with more care, we might have been far advanced in the knowledge of many arts, which are yet in their in- fancy, 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 valu- able improvements in achromatic glasses. Reaumur has given a very interesting account of the wasps of Cayenne, which hang their nests in trees.* Like the bird of Africa called the Loxia, they fabricate a perfect house, capable of containing 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 card- maker; — and travellers of veracity agree that 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 manu- iacturer of this substance might be proud of the work. The nest of the card-making wasp is impervious to water. It hangs upon the branch of a tree, as represented in the engraving; and those rain-drops * Memoires sur les Insectes, torn vi.j mem. vii. See also Bomiet> vol. ix. 88 INSECT ARCHITECTURE. which penetrate through the leaves never rest upon its hard and pohshed surface. A small opening for the entrance of the insects terminates its funnel- shaped bottom. It is impossible to unite more per- fectly the qualities of lightness and strength. Nest of the Cai-d-mul-crJfasp, with part removed to shcx the arrunoement of the Cells. Chapter V. Architecture of the Hive-Bee. Part of a koncyconih^ and hees at work. Although the hive-bee {^Jlpis mellifica) has engaged the attention of the curious from the earliest ages, recent discoveries prove that we are yet only begin- ning to arrive at a correct knowledge of its wonderful proceedings. Pliny informs us that Aristomachus, of Soles, in CiUcia, devoted fifty-eight years to the study; and that Philiscus the Thracian spent his whole life in forests for the purpose of observing them. But in consequence (as we may naturally infer) of the imperfect methods of research, as- VOL. IV. 8* 90 INSECT ARCHITECTURE. suming 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 Virgil, to be nothing more than conjecture, almost in every par- ticular erroneous. It was not indeed till 1712, when glass hives were invented by Maraldi, a mathema- tician of Nice, that what we may call the in-door proceedings of bees could be observed. This im- portant invention was soon afterwards taken advan- tage of by M. Reaumur, who laid the foundation of the more recent discoveries of John Hunter, Schi- rach, and the Hubers. The admirable architecture which bees exhibit in their miniature cities has, by these and other naturalists, been investigated with great care and accuracy. We shall endeavour to give as full an account of their wonderful structures as our limits will allow. In this we shall chiefly follow M. Huber, the elder, whose researches appear almost miraculous when we consider that he was blmd. At the early age of seventeen this remarkable man lost his sight by giifta serena, "the drop 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 reason- ings pointed out to her all that he wanted to ascer- tain; and as she reported to him from time to time the results of his ingenious experiments, he was en- abled to complete, by diligent investigation, one of the most accurate and satisfactory accounts of the habits of bees which has ever been produced. This venerable naturalist is, we believe, still alive. It had long been known that the bees of a hive consist of three sorts, which were ascertained by HIVE-BEES. 91 M. Reaumur to be distinguished as workers or neuters, constituting the bulk of the population; drones or males, the least numerous class; and a sin- gle female, the queen and mother of the colony. Schi- rach subsequently discovered the very extraordinary fact, which Huber and others have proved beyond doubt, that when a hive is accidentalty 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 discovery of M. Hu- ber is of more importance to the subject of archi- tecture now before us. By minute research he ascer- tained, 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-bees are rather smaller than the wax- workers, and even when gorged with honey their belly does not, as in the others, appear 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 wax^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 repeated experiments. He also ascertained that neither of the species 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- * It is right to remark that Huish and others have suggested that the grubs thus royalized may originally Ije misplaced queens; yet this admission is not necessary, since Madlle. Jurine has proved, by dissection, tlie workers to be imperfect females. Sfx INSECT ARCHITECTURE ment, after supplying a hive deprived of a queen with brood and pollen, he saw the nurse-bees quickly oc- cupied 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 reception, 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 provision 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 re- moved except in case of extreme necessity, and when honey is not to be otherwise procured. The cells are at no time opened during summer; other reservoirs, always exposed, contribute to the daily use of the community; each bee, however, sup- plying itself from them with nothing but what is required for present wants. Wax-workers appear 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 concur- rence of circumstances not invariably subsisting. Nurse-bees also produce wax, but in a very inferior quantity to what is elaborated by the real wax-v«orkers. Another characteristic whereby an attentive observer 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 93 worked in wax in his own hives, and in those of the other cultivators of the district. There is still another sort of bees, first observed by Huber in 1809, 'which appear to be only casual in- mates of the hi\e, and which are driven forth to starve, or are killed in conflict. They closely resem- ble 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 defec- tive bees;* but Kirby and Spence conjecture that they are toil-worn superannuated workers, of no farther use, and are therefore sacrificed, because bur- densome to a community which tolerates no un- necessary inmates. The very great numbers of black bees, however, which sometimes appear, does not well accord with such an opinion. The subject remains, therefore, still in uncertainty. 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 pro- vided with the materials — \vith the wax, in short, of which they are principally formed. Before we follow them, therefore, to the operation of building, it may be necessary to inquire how the wax itself is pro- cured. Here the discoveries of recent inquirers have been little less singular and unexpected than in other departments of the history of these extraordinary in- sects. 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, * Huber on Bees, p. 338. 94 IXSECT ARCHITECTURE. 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 R'aumur, and particularly Bonnet, though both of them in general shrewd and accurate observers, were partially de- ceived by appearimces. The bees, we are erroneously told, search for wax " upon all sorts of trees and plants, but especially the rocket, the singular poppy, and in general all kinds of flowers. They amass it with tlieir 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 Avith 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 burden fixed and steady till they return home. They are sometimes exposed to incon • yeniences 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 re- turns to the flowers; and when they have stocked themselves with a suflicicnt quantity, they imme- diately repair to their habitation. Two men, in the compass of a whole dav, could not amass so much as two little balls of wax; and yet they are no more than the common burthen of a single bee, and the produce of one journey. Those who arc employed * ftleliaselogia, or Female Monarchy, 8vo., Loud. 1744. HIVE-BEES. 95 in collectmg the wax from flowers are assisted by their companions, who attend them at the door of the hive, ease 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, whilst those who disburthened them convey their charge to the magazine. But some bees, again, when they have brought their load home, carry it tliemselves to the lodge^ and there deliver it, laying hold of one end by their hinder feet, and with their middle feet sliding it out of the cavity that con- tained it; but this is evidently a work of supereroga- tion which they are not obliged to perform. The packets of wax continue a few moments in the lodge, till a set of othcers come, who are charged with a third commission, which is to knead this wax with their feet, and spread it out into different sheets, laid one above another. This is the unwrought wax, which is easily distinguished to be the produce of different flowers, ])y the variety of colours that appear on each sheet. When they afterwards come to work, they knead it over again, they purify and whiten, and then reduce it to a uniform colour. They use this wax with a wonderful frugality ; for it is easy to observe that the vvhole family is conducted by pru- dence, and all their actions regulated by good go- vernment. 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."* Ri'aumur hesitated in behoving that this was a. - Plqche, Spectacle de la Nature, vol. i. 96 INSECT ARCHITECTURE. correct view of the subject, from observing the great difference between wax and pollen; but he was in- clined to think the pollen might be swallowed, par- tially 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. The celebrated John Hunter shrewdly remarked that the pellets of pollen seen on the thighs of bees are of different 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 com- plete, 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 pre- vented from going abroad, as much comb was con- structed 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 conclu- sion that it was an external secretion originating between the plates of the belly. When he tirst ob- served this, he felt not a little embarassed to explain the phenomenon, and doubted whether new plates were forming, or whether bees cast the old ones as lobsters do their shells. By melting the scales, he ascertained at least that they were wax; and his opinion was confirmed by the lact, that the scales are only to be found during the season when the combs are con^ structed. But he did not succeed in completing the discovery by observing the bees actually detach the HIVE-BEES. 97 scales, though he conjectured they might be taken up by others, if they were once shaken out from between the rings.* We jieed 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 tall only on them. The exposure 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, we can always travel more securely in the way of truth. That wax is secreted, is proved both by the wax pouches within the rings of the abdomen, and by actual experiment. I Huber and others fed bees entirely upon honey or sugar, and, notwithstanding, wax was produced and combs formed as if they had been at liberty to select their food. " When bees were confined," says M. Huber, " tor the purpose of discovering whether honey was sufficient for the production of wax, they supported their captivity patiently, and showed uncommon perseverance in rebuilding their combs as we removed them. Our experiments required the presence of grubs; honey and water had to be provided; the bees were to be supphed with combs containing brood, and at the same time it was necessary to con- fine them, that they might not seek pollen abroad. Having a swarm by chance, which had become use- less from sterility of the queen, we devoted it for our investigation in one of my leaf hives, which was glazed on both sides. We rtnioved the queen, and substituted combs containing eggs and young grubs, - but no cell with farina; even the smallest particle of * Philosophical Trans, for 1792, p. 143. i See p. 103. VOL. IV. 9 98 INSECT ARCHITECTURE. the substance which John Hunter conjectured to be the basis of the nutriment of the young, was taken away. " Nothing remarkable occurred during the first and second day: the bees brooded over the young, and seemed to take 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 shut- ter, and saw all in confusion; the brood was aban- doned; the workers ran in disorder over the combs; thousands rushed towards the lower part of the hive; jmd 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 elsewliere what they could not find in the liive; and apprehensive 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, tliey 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 circumstances calmed their agitation; for we observed them peaceably remounting their combs; order seemed re-established, and wo took advantage of this moment to close the hive. " Next day, the 19tli of July, we saw tlie rudiments of two royal cells, which the bees had formed on ojie of the brood combs. This evening, at the same hour as on the proceeding, 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 returned as before. We remarked on the 20th, that the royal cells had not been continued, as would have been the case in the ordinary state of things. A great tumult HIVE-BEES. 99 took place in the evening ; the t3ees appeared to be in a dehrium ; we set them at Hberty, 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 progress ; and we wished 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 immediately 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 like- wise ; no brood, not an atom of paste was in them. Thus, the worms had died of hunger. Had we pre- cluded the bees from all means of sustenance 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 afler 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 consohdated the combs, and remained on the brood. They were then provided with fragments of combs, where other workers had stored up farina ; 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 farina 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. 100 INSECT ARCHITECTURE. 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 opened 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 quantity of pollen only to impart it to their young. 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 farther, 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 found 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 entrusted with rearing, that we shall not seek for any other explanation of their conduct. Another fact, no less extraordinary, and much more difticult 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 begin- ning these had received the usual attention. They even frequently dragged them from their cells, and carried them out of the hive."* Mr Wiston, of Germantown, in the United States, * Iluber on Bees. IIIVE-BEES. 101 mentions a fact conclusive on this subject. " I had," says he, " a late swarm last summer, which, in con- sequence of the drought, tilled only one box with honey. As it was late in the season, and the food collected Avould 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 box, 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, I traced some wild bees, which had been feeding on the flowers in my meadow, to their home m 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 linibs 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 be- low, 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 contained the hive, sepa- rated 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 jxirt of the top of the block, the inte- rior 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 fi-om abroad. In the fol- VOL. IV. 9* 102 INSECT ARCHITECTURE. lowing 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.* In another experiment, M. Huber confined a swarm so that they had access to nothuig beside honey, and five times successively removed the combs with the precaution of preventing the escape of the bees from the apartment. On each occasion they produced new combs, which puts it beyond dis- pute 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 nothmg but farina, they neither made wax, nor was any secreted under the rmgs. In another series 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, Madlle, Jurine, and Latreille. The first stomach of the Vv'orker-bee, according to Latreille,"]" is appropriated to the reception of honey, but this is never found in the second stomach, which is surrounded with muscular rmgs, and from one end to the other very much resembles a cask covered with hoops. It is within these rings that the wax is produced, but the secreting vessels for this purpose have hitlierto escaped the researches of the acutest * AmericanQuarterly Review for June, 1828, p. 382. t Latreille, Mem. Acad, des Sciences, 1821. HIVE-BEES. 103 naturalists. Huber, however, plausibly enough conjec- tures that they are contained in the ineternal linmg of the wax pockets, which consists of a cellular substance reticulated with hexagons. The wax pockets them- selves, which are concealed by the over-lapping of the rings, may be seen by pressing the abdomen of a worker-bee so as to lengthen it, and separate the rings further fiom each other. When this has been done, there may be seen on each of the tour mtermediate 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 ibrm of a trapezium. Within, the little scales or plates of wax ^^'^■^.^.^ -^■^^ Woi-l-cv-bae, magnified — showing the position of the scales of Wax. are produced from time to tmie, and are removed and employed as v/e 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 only in very small quan- tities, while in the queen bee, and the males or drones, no pockets are discoverable. 104 i?;sccT ARcn'itiTcTLTit:. Abdomen of Queen Bcc. " All the scales," says Huber, "are not alike m every bee, fur a diftereuce is perceptible in consist- ence, shape, and thickness; some are so thin and transparent, as to require a magnifier to be recog- nised, or we have been able to discover nothing but spicvdtc similar to those of water freezing. Neither the spicula3 nor the scales rest immediately on the mem- brane 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 otheiwise they might adhere too firmly to the sides of the pockets." M. Huber has seen the scales so iarge as to project lieyond the rings, being visible without stretching the segments, and of a whitish- yellow, ffom greater thickness lessening tlieir trans- parency. These shades of diflerence in the scales of various bees, their enlarged dimensions, the fluid in- terposed l)encath them, the correspondence between the scale, and the size and form of the pockets, seem to infer the oozing of this substance through the mem- HIVE-BEES. 105 branes whereon it is moulded. He was confirmed in this opinion by the escape of a transparent fluid on piercing the membrane, Avhose internal surface seemed to be apphed to the soft parts of the belly. This he found coagulated in cooling, when it re- sembled wax, and again liquified 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 m ether, and but partially soluble m spirit of turpentme. It should seem to tbllow, that if the substance found lymg under the rings be really the elements of wax, it undergoes some subsequent pre- paration after it is detached; and that the bees, in short, are capable of impregnating it with matter, imparting to it whiteness and ductility, whereas in its unprepared state it is only fusible. PHOPOLIS. Wax is not the only material employed by bees in their architecture. Besides this, they make use of a brown, odoriferous, resmous substance, called pro- volis,'\ more tenacious and extensible than wax, and well adapted for cementmg and varnishing. It was strongly suspected by Reaumur, that the bees collect- ed the propolis from those trees which are known to produce a sunilar gummy resm, such as the poplar, the birch, and the willow; but he was thrown into doubt by not being able to detect the bees in the act of procuring it, and by observhig them to collect * Iluber on Bees, p. 325. t From two Greejc words tr^o ttoxk meaning before the city, as the substance is principally applied to the projecting parts of the hive. 106 INSECT ARCHITECTURE. it where none of those trees, nor any other of the same description, grew. His bees also refused to make use of bitumen, and other resinous substances, with whicli he supplied them, though Mr Knight, as we shall afterwards see, was more successful.* Long before the time of Rt aumur, however, Mouf- fet, in his Insecfarum Thcafrinn, quotes Cordus for the opinion, that propolis is collected from tlie buds of trees, such as the poplar and birch; and Reim says it is collected fi-om the pine and fir.t Huber at length set the question at rest; and his experi- ments and observations are so interesting, that we shall give them m his own words: — " For many years," says he, " I had fruitlessly en- deavoured to find them on trees producing an ana- logous substance, though multitudes had been seen returning laden with it. " In July, some branches of the Avild poplar, Avhich 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 separatmg the sheath of a bud with its teeth, drew out threads of the 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 oppo- site limb, and departed to the hive. A second bee took the place of the former in a few minutes, fol- lowing the same procedure. Young shoots of poplar, recently cut, did not seem to attract these insects, as their viscous matter had less consistence than (ho former. J * Phil. Trans, for 1807, p. 212. t Sohirach, Hist, des Abeilles, p. 211. t Kirby and Spcncc observed bees very bu^y in rolled iii;^ HIVE-BEES. 107 " Different experiments proved the identity of this substance Avith propohs; and now, having only to discover how the bees apphed it to use, we peopled a hive, so prepared as to fulfil our views. The bees, building upwards, soon reached the glass above ; but, unable to quit their habitation, 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 ob- servations. Serene warm weather engaged them to forage, and they returned from the fields laden with a resinous gum, resembling 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 workers bearing the propohs ran over the clusters suspended from the roof of the hive, and rested on the rods supporting the combs, or sometimes stopped on the sides of their dweUing, in expectation of their companions coming to disencumber them of their burden. We actually saw two or three arrive, and carry the propolis from off the limbs of each with their teeth. The upper part of the hive exhibited the most animated spec- tacle: thither a multitude of bees resorted from all quarters, to engage in the predominant occupation of the collection, distribution, and application 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 spread it out like a varnish, or formed it into strings, proportioned to the interstices of the sides of the hive to be filled up. Nothing could be more diver- sified than the operations carried on. " The bees, apparently charged with applying the propolis from the tacamahacatree {Populus balsamifcra.) — ■ Introd.j ii. 186. 108 INSECT ARCHITECTURE. propolis within the cells, were easily distinguished from the multitude of workers, by the direction of their heads towards the horizontal pane forming the roof of the hive, and on reaching it, they deposited their burden nearly in the middle of intervals sepa- rating the combs: then they conveyed the propohs to the real place of its destination. They suspended themselves by the claws of the hind legs to points of support, afforded by tlie viscosity of the propohs on the glass; and, as it were, swinging themselves back- wards and forwards, brought the heap of this substance nearer to the cells at each impulse. Here the bees em- ployed their fore feet, which remained free, to sweep what the teeth had detached, and to unite the frag- ments 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 do\\n and cleaned out the glazed cells, feeling the way with their antennae, one desisted, and having approached a heap of propohs, 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, imme- diately 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 tlie accuracy M'ith which it was ad- justed when the work was completed. The insect did not stop here: returning to the cell, it prepared other parts of it to receive a second thread, for which we did not doubt that the heap would be resorted to. Contrary to our expectation, however, it availed itself of the portion of tlic tlircad 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 concluded the work which the first had begun; and the sides of the cells weie HIVE-BEES. 109 speedily secured with threads of propolis, while some were also put on the orifices ; but we could not seize the moment when they were varnished, though it may be easily conceived how it is done."* This is not the only use to which bees apply the propohs. They are extremely solicitous to remove such insects or foreign bodies as happen to get ad- mission into the hive. When so light as not to exceed their powers, they first kill the insect with their stings, and then drag it out with their teeth. But it sometimes happens, as was first observed by Maraldi, and since by Reaumur and others, that an ill-fated snail creeps 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 co- vering every part of its body with propohs, through which no effluvia 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 re- ceives the first wound from a sting, it naturally retires within its shell. In this case, the bees, instead of pasting it all over with propohs, content them- selves with gluing all round the margin of the shell, which is sufficient to render the anunal for ever im- movably fixed. Mr Knight, the learned and ingenious President of the Horticultural Society, discovered by accident an artificial substance, more attractive than any of the resins experimentally tried by Reaumur. Having caused the decorticated part of a tree to be covered with a cement, composed of bees'-wax and turpentine, he observed that this was frequented by hive-bees, who, finding it to be a very good propohs ready made, * Huber on Bees, p. 408. VOL. IV. 10 no iNSECT ARCHITECTURE. detached it from the tree by their mandibles, and then, as usual, passed it from the iirst 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 manitesting any signs of anger.* 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 exemplitied in every part of the economy of bees. It mav 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 JVIr 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 Stru'-turcof the hgi of the Bee for caryjini^ propjis and pollen, mas^nificd. " Philosophical TiaiiP. for IPOT, p. 242. HIVE-BEES. Ill is composed of ~ a smooth, shining, horn-like sub- stance, liollowed 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, are 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 first 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 some- times occupies nearly half an hour. She then passes it backwards by means of her feet to the cavity of her basket, giving it two or three pats to malte it adhere; and when she adds a second portion to the first, she often finds it necessary to pat it still harder. When she has procured as much as the basket will conve- niently hold, she flies otT with it to the hive. The Building of the Cells. The notion commonly entertained respecting glass hives is altogether erroneous. Those who are un- acquainted v.ith bees imagine, that, by means of a glass hive, all their proceedings may be easily watched and recorded; but it is to be remembered that bees are exceedmgly 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 disturb them, either by clustering together, or by a plaster com- posed of propolis. It consequently requires con- siderable 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 112 INSECT ARCHITECTURE. 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 sufiicient to obviate tvery difficulty. The bees are so eager to afford nv tual assistance, and for this purpose so niany of them crowd together in rapid succession, that the operations of individuals can seldom be traced. Though this crowding, however, appears to an observer to be not a little confused, it is all regulated with admirable order, as has been ascer- tained by Reaumur and other distinguished natu- ralists. When bees begin to build the hive, they divide themselves into bands, one of which produces mate- rials for the structure; 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, re- move the superfluous wax, and give the work its ne- cessary perfection; and a third band brings provi- sions to the labourers, who cannot leave their work. J3ut no distribution of food is made to those whose charge, in 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 troublesome, because they are obliged to level and extend, as well as cut and adjust the wax to the dimensions required; but tlien they soon ob- tain a dismission from this labour, and retire to the fields to regale themselves Vvith food, and wear off their fatigue with a more agreeable employment. Those T,, ho succeed them, draw their moutli, 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, HIVE-BEES. 113 there are waiters always attending, who serve them with provisions when they require thein. 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 whole of his trunk, which in- sensibly 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 mo- tions 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 propohs, 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 appear, 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 a curtain which is composed of a series of mtertwined festoons or garlands, crossing each other in all directions, — the uppermost bee maintaining its position by laying hold of the roof with its fore-legs, and the succeeding one by laying hold of the hind legs 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 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 their labours. The bees composing the festooned curtain are individu- ally motionless; but this curtain is, notwithstanding, * Spectacle de la Nature, torn. i. VOL. IV. 10* 114 INSECT ARCHITECTURE. kept moving by the proceedings in Ihe interior; for the nurse-bees never form any portion of it, and continue their activity— a distinction with which Reaumur was unacouainted. y#^*' \ Curtain o/ Wax-zmrJccrs secreting Wax. Although there arc many thousand labourers in a hive, they do not commence foundations for combs HIVE-BEES. 115 ill several places at once, but wait till an individual bee has selected a site, and laid the foundation of a comb, which serves as a directing mark for all that are to follow. ^Yere we not expressly told by so accurate an observer as Huber, we might hesitate to believe that bees, though united in what appears to. be a harmonious monarchy, are strangers to sub- ordination, 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 suc- cessive. An individual bee commences each opera- tion, and several others successively apply themselves to accompUsh the same purpose. Each bee appears, therefore, to act individually, either as directed by the bees preceeding it, or by the state of advancement in which it finds the v/ork it has to proceed with. If there be anytliing like unanimous consent, it is the inaction of several thousand workers while a single individual proceeds to determine and lay down the foundation of the first comb. Reaumur regrets, that, though he could by snatches detect a bee at work in founding cells or perfecting their structure, his ob- servations were generally interrupted by the crowding of other bees between him and the little builder. He was therefore compelled rather to infer the dif^ ferent steps of their procedm-e from an examination of the cells when completed, than from actual ob- servation. The ingenuity of Huber, even under all the disadvantages of blindness, succeeded in tracing the minutest operations of the workers from the first waxen plate of the foundation. We think the narra- tive of the discoverer's experiments, as given by him- self, will be more interesting than any abstract of it which we could furnish. " Having taken a large bell-shaped glass receiver, we glued thin wooden slips to the arch at certain in- 116 INSECT ARCHITECTURE. tervals, because the glass itself was too smooth lo admit of the bees supporting themselves on it. A swann, consisting of some thousand workers, several hundred males, and a fertile queen, was introduced, and they soon ascended to the top. Those first gaming 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, hangmg like an inverted pyramid from the top to the bottomof the hive. " The country then affording little honey, we pro- vided 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, re- turned 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 propths. The wax-workers remained motionless above fifteen hours: the curtain of bees, consisting always of the same individuals, assured us that none eplaced 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, tlie rings seemed edged with white. The curtain of bees became rent in several places, and some commotion began to be observed in the hive. " Convinced that the combs would originate in 117 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 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 projecting from a ring, and brought it forward to its mouth with the claws of its fore-legs, Wax-worker laying the foundation of the first Cell- where it appeared in a vertical position. We re- marked, that, Avith 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 mandi- bles, issued forth like a very narrow ribbon, impreg- nated with a frothy liquid by the tongue. The tongue itself assumed the most varied shapes, and executed the most comphcated 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 apphed these particles of wax to the vault of the hive, where the saliva impreg- nating them promoted their adhesion, and also com- 118 INSECT ARCHITECTURE. municated a whiteness and opacity, which where want- ing 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 ap- plied to use with its mandibles, and with the same organs afterwards arranged them at pleasure. The founder bee, a name appropriate to this worker, re- peated the same operation, until all the fragments, worked up and impregnated with the fluid, were attached to the vault, Avhen it repeated the preceding operations 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 nothmg but accumulate the par- ticles of wax together. Meanwhile, the founder, quitting its position, disappeared amidst its com- panions. Another, with wax under the rings, suc- ceeded it, which, suspending itself to the same spot, withdrew 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, and put them near the materials accumulated by its companions, but not in a straight line. Ano- ther bee, apparently 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 surface, hanging down from the arch, without any perceptible angle, or any traces of cells. It was a simple wall, or ridge, runnmg in a straight line, and without the least inflection, two-thirds of HIVE-BEES. 119 an inch in length, about two-thirds of a ceU, or two hnes, high, and decUning 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 per- mitted us to discover the first manoeuvres of the bees, and the art with which they laid the foundations of their edifices. However, it was filled up too soon for our satisfaction; for workers collecting on both faces of the wall obstructed our view of then further operations."* Huber on CwtaU of n Chapter VI. Architecture of the Hive-Bee continued Form of the Cells. The obstruction of which IM. Huber complains only operated as a stimulus to his ingenuity in contriving how he might continue his interesting observations. From the time of Pappus to the present day, mathe- maticians have applied the principles of geometry to explain the construction of the cells of a bee-hive; but though their extraordinary regularity, and won- derfully selected form, had so often been investigated by men of the greatest talent, and skilled in all the refinements of science, the process by which they are constructed, involving also the causes of their regu- larity of form, had not been traced, till JVI. Huber devoted himself to the inquiry. As the wax-workers secrete onlv a limited quantity of wax, it is indispensably requisite that as little as possible of it should be consumed, and that none of it should be wasted. Bees, therefore, as M. Rt aumur well remarks,* have to solve this difficult geometrical problem: — A quantity of Avax being given, to foiin of it similar and equal cells of a determinate capa- city, but of the largest size in proportion to the quantity of matter employed, and disposed in such a manner as to occupy the least possible space in the hive. This problem is solved by bees in all its con- ditions. The cylindrical form would seem to be best adapted to the shape of the insect; but had the cells been cylindrical, they could not have been applied to ■* Reaumur, vol. v. p,3S0, HIVE-BEES. 121 each other Avithout leaving a vacant and superfluous space between every three contiguous cells. Had the cells, on the other hand, been square or triangular, they might have been constructed without unnecessary vacancies; but these forms would have both required more material and been very unsuitable to the shape of a bee's body. The sLx-sided form of the cells obviates every objection; and wliile it fulfils the con- ditions of the problem, it is equally adapted \vith a cylmder to the shape of the bee. M. Reaumur further remarks, that the base of each cell, instead of forming a plane, is usually com- posed of three pieces in the shape of the diamonds on playmg cards, and placed in such a maimer as to form a hollow pyramid. This structure, it may be observed, imparts a greater degree of strength, and, stUl keeping the solution of the problem m view, gives a great capacity with the smallest expenditure of material. This has actually, mdeed, been ascertained by mathematical measurement and calculation. Ma- raldi, the inventor of glass hives, determined, by minutely measuring these angles, that the greater were 109° 28', and the smaller,- 70« 32'; and M. Reaumur, being desirous to know why these parti- cular angles are selected, requested M. Koenig, a skilful mathematician, (without informing liim of liis design, or telling him of Maraldi's researches,) to determuie, 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 de- nonunate the infinitesimal calculus^ M. Koenig 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 equahty of mclination in the VOL. IV, 11 122 INSECT ARCHITECTURE, 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 irre- gular four-sided figure. This arrangement, by bring- ing the greatest number of points in contact with the interior surface, ensures the stability of the comb. Arrangement of CeHs. It may, however, be said not to be quite certain, that Reaumur and others have not ascribed to bees the merit of ingenious mathematical contrivance and selection, when the construction of the cells may more probably originate in the form of their mandibles and other instruments employed in their operations. In the case of other insects, we have, both in the preced- ing and subsequent pages of this volume, repeatedly noticed, that they use their bodies, or parts thereof, as the standards of measurement and modelling; tmd it is not impossible that bees may proceed on a similar principle. M. Huber replies to this objection, HIVE-BEES. 123 that bees are not provided with instruments corre- sponding 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, he thinks, does not furnish any better explana- tion. He admits that the antennae are very flexible, so as to enable the insects to follow the outline of every object; but concludes that neither their struc- ture, nor that of the limbs and mandibles, are ade- quate 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 he contrived, in order to observe the opera- tions of the bees subsequent to their laying a founda- tion for the first cell ; and we shall again quote from his own narrative: — " It appeared to me," he says, " that the only method of isolating the architects, and bringing them individually into view, would be to induce them to change the direction of their operations, and work upwards. " I had a box made twelve inches square and nine deep, with a moveable glass lid. Combs full of brood, honey, and pollen, were next selected from one of my leaf hives, as containing what might in- terest 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 precluded the swarm from adhering to it; therefore, if disposed to build, 124 INSECT ARCHITECTURE. they could do so over the slips resting on the combs, which lefl a vacuity five inches high above them. As we had foreseen, the swarm wth which this box was peopled established itself among the combs below. We then observed the nurse-bees displaying their natural activity. They dispersed themselves through- out the hive, to feed the young grubs, to clear out their lodgment, and adapt it for their convenience. Certainly, the combs, which were roughly cut to fit the bottom of the box, and in some parts damaged, appeared to them shapeless and misplaced ; for they speedily commenced their reparation. They beat down the old wax, kneaded it between their teeth, and thus formed binding materials to consolidate them. We were 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 pru- dence. " But it was still more wonderful, that about half the numerous population took no part in the pro- ceedings, remaining motionless, while the others ful- filled the functions required. The wax-workers, in a state of absolute repose, recalled our former obser- vations. 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 be put in operation. To our great satisfaction we soon saw a little foun- dation wall rising on one of the slips that we had prepared to receive the superstructure. ISo obstacle was offered to the progress of our observations; and for the second time, \vc beheld both the undertaking of the founder bee, and the successive labours of several wax-workers, in forming the foundation wall. Would that my readers could share the interest which the view of these architects inspired! HIVE-BEES. 125 " This foundation, originally very small, was en- larged as the work required; while they excavated on one side a hollow, of about the width of a com- mon cell, and on the opposite surface two others somewhat more elongated. The middle of the single cell corresponded exactly to the partition separating the latter; the arches of these excavations, projecting 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. Foundution-wall enlarged, and the cells coihmenced. " The interior conformation of the cavities, ap- parently, was derived from the position of their re- spective outlines. It seemed that the bees, endowed with an admirable delicacy of feeling, directed their teeth principally to the place where the wax was thickest; that is, the parts where other workers on the opposite side had accumulated it; and this ex- plains 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 excavations, which was op- posite to three others, was divided into three 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 ex- cavations were opposed to each other, those of the second row, and all subsequent, partially appHed to three cavities, were composed of three equal diamond- VQL IV. 11* 126 INSECT ARCHITECTURE. 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 nui'se-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 moistening the particles, deposited them on the edge of the excavation. 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 projectmg 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 equally a cell in width, a bee left the swarm, and after encircling the block, commenced its operations 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 tlie lace that had been untouched, wherein both were occupied in forming cavities, which may be designed the second and third; and they also were replaced by substi- tutes. These two latter cavities were separated only by the common margin, framed of particles of wax withdrawn from them; which margin corresponded with the centre of the cavity on the opposite surface. HIVE-BEES. 127 The foundation wall itself was still of insufficient dimensions to admit the full diameter of a cell; but while the excavations were deepened, wax-workers extracting their scales of wax applied them in enlarg- ing its circumference ; so that it rose nearly two lines further around the circular arch. The nurse-bees, which appeared more especially charged with sculp- turing 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 project- ing 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 operations of the bees, from their frequently inter- posing their heads between the eye of the observer and the bottom of the cell; but the partition, whereon their teeth laboured, 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 partly behind those in front — for in general, their 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 will carry on the adjacent cells.' Farther, 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 128 INSECT ARCHITECTURE. whole subservient to each other. It is undoubted, therefore, that slight irregularities on the front will affect the form of the cells on the back of the comb."* When they have in this manner worked the bot- toms of the first row of cells into the required forms, some of the nurse-bees finish them by imparting a sort of polish, while others proceed to cut out the rudiments of a second row from the 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 contour of all the bot- toms, 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 simple, than adding wax to the mar- gins; but from the inequalities occasioned by the shape of the bottom, the bees must accumulate wax on the depressions, in order to bring them to a level. It follows accordingly that the surface 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 precednig 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, tliat while sketching the bottom of a cell, before there was any upriglit mar- gin on the reverse, their pressure on the still soli * Huher on Bees, n. 368. HIVE-BEES. 129 and flexible wax gave rise to a projection, which sometimes caused a breach of the partition. This, however, was soon repaired, but a, sHglit prominence always remained on the opposite surface, to the right and left of which they placed themselves, to begin a new 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 the vertical furrow of the front cell. We have already seen that the first cell determines the place of all that succeed it, and two of these are never in ordinary circumstances begun in different parts of the hive at the same time, as is alleged by some earlier writers. When some rows of cells, however, have been completed in the first comb, two other foundation"^valls 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 op- posite 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 may call the highways of the community, the combs are pierced in several places with holes which serve as postern-gates for easy communication from one to another, to prevent loss of time in going round. The 130 INSECT ARCHITECTURE, equal distance between the combs is of more impor- tance to the welfare of the hive than might at first appear; for were they too distant, the bees would be so scattered and dispersed, that they could not re- ciprocally 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 with 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 their communi- cations to be so spacious and free. On the return of spring, the bees hasten to contract the elongated cells, that they may become fit for receiving the eggs which 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 Edin- burgh, 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 account of his discovery in his oAvn words : — " Having inquired of several naturalists whether or not they knew any author who had mentioned that the partitions between the cells of the honey- comb were double, and whether or not they had ever remarked such a structure themselves, and they hav- ing 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 par- titions between difl^erent cells, at the sides and the * Huber on Bees, p. 220. HIVE-BEES. 131 base, are all double; or, in other words, that each cell is a distinct, separate, and in some measure an independent structure, agghitinated only to the neigh- bouring cells ; and that when the agglutinating sub- stance is destroyed; each eel! may be entirely sepa- I'ated tiom the rest. " 1 have ;>lso some specimens of the cells formed by wasps, which shew that the partitions between them are also double, and that the agglutinating sub- stance between them is more easily destroyed than that between the cells of the bee."* Irregularities in their Workmanship. Though bees, however, work with great uniformity when circumstances favour their operations, they may be compelled to vary their proceedings. IVI. Huber made several ingenious experunents of this kind. The following, mentioned by Dr Bevan, was acci- dental, and occured to his friend Mr Walond. '' Inspecting liis bee-boxes at the end of October, 1817, he perceived that a centre comb, burdened with honey, had separated from its attachments, and was leaning Eigainst another comb, so as to prevent the passage of the bees between them. This acci- dent excited great activity in the colony; but its nature could not be ascertained 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 pUlars 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 unin- terrupted thoroughfare; the detached comb at its upper part had been secured by a strong barrier, and * Memoirs of the Wernerian Nat. Hist. Soc. vol. ii. p. 269- 132 INSECT ARCHITECTURE. fastened to the window with the spare wax. This being accomphshed, the bees removed the horizontal pillars first constructed as being of no further use."* A similar anecdote is told by M. Huber. " Dur- ing the winter," says he, " a comb in one of my bell-glass hives, having 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 favour- able season they would have ingrafted a new comb on the old one; but now their provision of honey could not be spared for the elaboration of this sub- stance, which induced them to ensure the stability of the comb by another process. " Crowds of bees taking wax from the lower part of other combs, and even gnawing it fi-om the sur- face of the orifices of the deepest cells, they con- structed so many irregular pillars, joists, or but- tresses, between the sides of the fallen comb, and others on the glass of the hive. All these were arti- ficially adapted to localities. Neither did they con- fine themselves to repairing the accidents which their works had sustained. They seemed to profit by the warning, to guard against a similar casualty. " The reniJiining combs were not displaced; there- fore, while solidly adhering by the base, we were greatly surprised to see the bees strengthen their principal fixtures with old wax. They rendered them much thicker than before, and fabricated a number of new connexions, 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 jiart of their hive, and when work is no longer seasonable, "f M. Huber the younger .shrewdly remarks, that * Bevan on Bees, p. 326. t Huber on Bees, p. 416. HIVE-BEES. 133 the tendency to symmetry observable in the archi- tecture of bees, does not hold so much in small de- tails as in the whole work, because they are some- times obliged to adapt themselves to particular loca- lities. 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 allow- ing, for instance, too little interval between the spars for receiving the foundation of the combs, the struc- ture 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 every where parallel to it, partook of the same curvature. But the bees did not rehsh such approaches to the " line of beauty," and exerted themselves to bring their buildings again into the regular form. In consequence of several in-egularities which they wished to correct, the younger Huber has seen bees depart from their usual practice, and at once lay on a spar two 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 contrivance : 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. " 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 VOL. IV. 12 134 INSECT ARCHITECTURE. 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 their combs perpendicular to one of these sides, and as regularly as those which they usually build under a horizontal surface. The foundations were laid on a place which does not serve naturally for the base, yet, except in the dif- ference of direction, the first row of cells resembled those in ordinary hives, the others being distributed 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 in- clmation to carry their combs, by the shortest way, to the opposite side of the hive (for they prefer uniting them to wood, or a surface rougher than glass), I covered it with a pane. Whenever this smooth and slippery substance was interposed be- tween them and the wood, they departed from the straight line hitherto followed, and bent the struc- ture of their comb at a right angle to what was al- ready made, so that the prolongation of the ex- tremity 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 their clustering on it. They al- ways sought the wooden sides. I thus compelled them to curve the combs in the strangest shapes, by placing a pane at a certain distance frozn their edges. These results indicate a degree of instinct truly wonderful. 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 HIVE-BEES. 135 polish. The most singular part of their proceeding is changing the direction of the work before arriving at the turlace of the glass, and while yet at a dis- tance suitable for doing so. Do they anticipate the inconvenience which would attend any other mode of building? iNo 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 estabhshing cells so small on one side, while dimen- sions 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 com- mon 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 mdividuals which shall be bred in them. The cells of males have the same figure, the same number of lozenges and sides as those of workers, and angles of the same size. Their diameter is 3i fines, 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 iso- lated. The manner in which they are surrounded by other cells alone can explain how the transition 136 INSECT ARCHITECTURE. 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 propor- tion 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, previously estabhsh a block or lump of wax on the edge of their comb, thicker than is usually employed for those of workers. It is also made higher, otherwise the 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 astonisliment had they observed that part of them are the 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 laiow 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 dimen- sions of their cells when there is an opportunity for a great collection of honey. Not only are they then constructed of a diameter much exceeding that of the common cells, but they are elongated throughout the whole space admitting it. A great portion of irre- gular comb contams cells an inch, or even an inch and a half, in depth. " Bees, on the contrary, sometimes are induced to shorten their cells. When wishing to prolong an old comb, whose cells have received their fidl dimen- sions, they gradually reduce the thickness of its edges, by gnawing down the sides of the cells, until they HIVE-BEES. 137 restore it to its original lenticular form. They add a waxen block around the whole circumference, and on the edge of the comb construct pyramidal bottoms, such as those fabricated on ordinary occasions. 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 de- molish the cells on the edges of the comb before en- larging it, unquestionably demands more profound in- vestigation. 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 ad- joining the edges of a comb recently constructed. 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 tino-ed with yellow, particularly on the interior sur- face; and their edges, from being thin, unitbrm, 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 around the orifices of the yellow cells, of reddish colour, unctuous, and odoriferous. 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 * Huber ou Bees, p. 391. VOL- IV. 1*2* 138 INSECT ARCHITECTURE. 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 sub- stance, diflerent from wax, had been employed in varnishing the orifices and strengthening the in- terior of the cells. M. Huber, by numerous ex- periments, 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 ana- logy. 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 ]>ollen. Perhaps it may he 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 pliant pencil, when it appears to leave some sprinkling of a trans- parent liquid. Beside painting and varnishing their cells in tliis manner, they take care to strengthen the weaker parts of their edifice by means of a mortar composed of propolis and wax, and named pissoceros* by the an- cients, who first observed it, though Reaumur was somewhat doubtfid respecting the existence of such a composition. We are indebted to the shrewd ob- servations of Huber for a reconcilement of the Roman and the French naturalists. The details Avhich he has given of his discovery are perhaps the most in- teresting in his delightful book. " Soon," he says, " after some new combs had been • * From two Greek words, signifying pitch and icax. HIVE-BEES 139 finished in a hive, manifest disorder and agitation pre- vailed among the bees. They seemed to attack their own works. The primitive cells, whose structure we had admired, were scarcely recognizable. Thick and massy walls, heavy, shapeless pillars, were substituted for the slight partitions previously built with such regu- larity. The substance had changed along with theform, being composed apparently of wax and propolis. From the perseverance of the workers in their devastations, we suspected that they proposed some useful akeration of their edifices; and our attention was directed to the cells least injured. Several were yet untouched; but the bees soon rushed precipitately on them, destroyed the tubes, broke down the wax, and threw all the fragments about. But v.-e remarked, that tlie bottom of the cells of the first row was spared; neither were the corresponding parts on both faces of the comb demoUshed at the same time. The bees laboured at them alternately, leaving some of the natural sup- ports, otherwise the comb would have fallen down, which was not their object: they wished, on the con- trary, 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 m drying, which probably ren- dered it more suitable for. the purpose. But the bees experienced some difficulty in making any impression on it; and we thought, as also had appeared to M. de Reaumur, that they softened it with the same frothy matter from the tongue which they use to ren- der 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 employed in rebuilding the cells J 40 INSECT ARCHITECTURE. that had been destroyed. But they did not now fol- low their ordinary rules of architecture, for they were occupied by the solidity of their edifices alone. Night intervening, suspended our observations, but next morning confirmed 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 constructed pimply of wax, as Il< aumur believed; and that after all the requisite conditions have been attained, it is converted to a mixture of wax and propolis, as remarked by PHny so many ages before us. Thus is the apparent contradiction be- tween these two great naturalists explained. But this is not the utmost extent of the forefight 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 intervals 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 con- structing great pieces of ■s\'ax 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 are built, the walls begin to stoop by de- grees, tliey nod with age, and bend from their '^per- pendicular;— lodgers damage everything, and time is continually introducing some new decay. The man- sions of bees, on the contrary, grow stronger the * Hiiber on Bees, p. 415. H»IVE-BEES. 141 oftener they change inhabitants. Every bee-grub, before its metamorphosis into a nymph, fastens its skin to the partitions of its cell, but in sucli a man- ner as to make it correspond with the hues of the angles, and without in the least disturbing the i-egula- rity of the figure. During summer, accordingly, the same lodging may serve for three or four grubs in succession; and in the ensuing season it may accom- modate an equal number. Kach grub never fails to fortify the panels of its chamber by arraying them with its spoils and the contiguous cells receive a si- milar augmentation from its brethren.* Ruaumur found as many as seven or eight of these skins spread over one another: so that all the cells being incrusted with six or seven coverings, well dried and cemented with propolis, the whole fabric daily ac- quires anew 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 pro- ceed, by turning the cells to other uses, such as ma- gazines for bee-bread and honey. It has been re- marked, however, that in the hive of a new swarm, during 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, in- deed, clean out the cell the moment that a young bee leaves its cocoon, but they never detach the silky film which it has previously spun on the walls of its cell. But though honey is deposited after the young 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 important class of nurse^bees. We are not disposed, however, to go quite so far as an American periodical writer, who says, " Thus we * Spectacle de la Nature, vol. i. 142 IXSECT ARCHITECTURE. see that the contraction of the cell may diminish the size of a bee, even to the extinction of life, just as the contraction of a Chinese shoe reduces the foot even to uselessness."* V/e know, on the contrary, that the queen bee will not deposit eggs, in a cell either too small or two large for the proper rearing of the young. In the case of large cells, M. Huber took advantage of a queen that was busy depositing the eggs of work- ers, to remove all the common cells adapted for their reception, and left only the large cells appropriated for males. As tliis was done in June, when bees are most active, he expected that they would have immediately repaired 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 slie did deposit six eggs in the large cells, which were hatched, as usual, three days after. The nurse-bees, however, seemed to be aware that they could not be reared there, and, though they supplied them with food, did not attend to them re- gularly. M. Huber found that they had been all re- moved from the cells during the night, and the busi- ness 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 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 * North American Rev., Oct. 1828, p. 355. HIVE BEES. 143 uncommon for swarms to stray from their 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 civihzation; and thus when the Indians observe a swarm they say " the white man is coming." There is evidence of bees iiaving abounded in these islands, in the earher periods of our history; and Ireland is particularly mentioned by the Venerable Bede as being " rich in milk and honey."* Ihe hive bee has formed an object of economical culture in Europe 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 clune of Southern Europe, any more than it is in our own island. The wild bees of Palestine principally hived in rocks. " He made him," says Moses, " to suck honey out of the rock.""]" " With honey out of the rock," says the Psalmist, " should 1 have satished 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 fissures, in such num- bers, as to become very troublesome to visiters. Their nests hang hi innumerable clusters. || We are told of a little black stingless bee found in the island of Gaudaloupe, which hives in hollow trees or in the cavities of rocks by the sea side, and lays " up honey 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 space between them. They hang in clusters almost like a bunch of grapes. "IT The following are men- tioned by Lindley as indigenous to Brazil "• On an * "Hibernia dives lactis ac melHs insula." — Beda, Hist. Ee. cles. i.,7. t Ueut. xxxii. 13. j: Psalm Ixxxi. 16, II Forbes, Orien. Mem. i. IT Amer. Q,. Rev., iii, p. 383, 144 INSECT ARCHITECTURE. 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 ponderous shell of clay cemented similarly to martin's nests, swelling from high trees about a loot thick, and forming an oval mass full two feet m diameter. When broken, the wax is arranged as in our hives, and the honey abundant."* Captain Basil Hall found in South America the hive of a honey-bee very diflerent 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 of the interior to more advantage. The honey is not contained in the elegant hexagonal cells of our liives, but in wax-bags, not quite so large as an egg. These bags or bladders are hung round the sides of the hive, and appear about half full; the quantity being probably just as great as the strength of the wax wUl bear without tearmg. 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 obsei-ved an irregularly-shaped mass of comb, furnished with cells like those of our bees, all containing young ones in such an advanced state, that, when we broke the comb, and let them out, they flew merrily away." Clavigero, in his History of JNIexico, evidently de- scribing the same species of bee, says it abounds in Yucatan, and malves the honey of Estabcntum, the finest m the world, and which is talien every two months. He mentioned another species of bee, smaller in size, and also without a sting, which forms its nest of the shape of a sugailoaf, and as large or larger. These are suspended from trees, particularly * Roy. Mill, riiron. quoted in Kirby and Spcnce. HIVE-BEES. 145 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 im- prudently attempted to rob a numerous hive of its honey, when the exasperated bees, rushing out to defend their property, attacked their assailants with great fury, and quickly compelled the whole com- pany to tly. At the Cape of Good Hope the bees themselves must be less formidable, or more easUy managed, as their hives are sought for with avidity. Nature has there provided man with a singular and very effi- cient assistant in a bird, most appropriately named the Honey-Guide {Indicator major, Yieillot; Cu- cuius indicator, Latham). The honey-guide, so far from being alarmed at the presence of man, appears anxious to court his acquaintance, and flits from tree to tree with an expressive note of invitation, the meaning of which is well known both to the colonists and the Hottentots. A person invited by the honey-guide seldom refuses to follow it on- wards till it stops, as it is certain to do, at some hollow tree containing a bee-hive, usually well stored with honey and wax. It is probable that the bu'd finds itself inadequate 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 hurt so useful a creature. The Americans, who have not the African honey- guide, employ several well-known methods to track bees to their hives. One of the mcst common though ingenious modes, is to place a piece of bee- VOL. IV. 13 146 INSECT ARCHITECTURE. bread on a flat surface, a tile for instance, surround- ing 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 ob- server 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, tor 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 secured 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. Departmg to some distance, he Uberates another, observes its comse, 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 remem- ber the expression of " Uning 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 num- merous species of social bees which, while they difler in many circumstances, agree in the practice of storing up honey, in the same way as we have nu- merous species of the mason bee and of the humble bee. Of the latter Mr Stephens emimerates no less than forty-two species indigenous to Britain. Chapter VII. Carpentry of Tree-Hoppers and t?a\v-Flies. The operations of an insect in boring into a leaf or a bud to form a lodgment for its eggs appear very simple. The tools, hov/ever, by which these effects are performed are very compli'cated and curious. In the case of gall-flies [Cynips,) the operation itself is not so remarkable as its subsequent chemical effects. These efliects are so different from any others that may be classed under the head of Insect Architecture, that we shall reserve them for the latter part of this vo- lume— 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, with- out 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 T£tt<|. The Romans called it Cicada, which we sometimes, but erroneously, trans- late "grasshopper;" for the grasshoppers belong to an entirely different order of insects. We shall, there- fore, take the liberty of calling the Cicadas, Tree- hoppers, to which the cuckoo-spit insect ( Tetiigonia spumaria, Oliv.) is allied; but there is only one of the true cicadce hitherto ascertained to be British, namely, the Cicada hannafodes (Li.nn.), which was taken in the New Forest, Hampshire, by Mr Daniel Bydder. M. Reaumur was exceedingly anxious to study the economy of those insects; but they not being indi- genous in the neighbourhood of Paris, he commis- 148 INSECT ARCHITECTURE. sioned his friends to send him some from more southern latitudes, and he procured in this way spe- cimens 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, as he tells us, he had never had the pleasure of seeing one of them alive, the more interesting parts of their structure can be studied as well in dead as in living specimens. We ourselves possess several specimens from JVew Holland, upon which -we have verified some of the more interesting observations of R'aumur. Virgil tells us, that in his time " the cicadoe burst the very shrubs with their querulous music;"* but we may well suppose that he was altogether unac- quainted with the singular instrument by means of which they can actually (not poetically) cut grooves in the branches they select for depositing their eggs. It is the male, as in the case of birds, which tills the woods with his song; while the female, though mute, is no less interesting to the naturalist on ac- count of her curious ovipositor. This instrument, like all those with which insects are furnished by nature for cutting, notching, or piercing, is com- posed of a horny substance, and is also considerably larger than the size of the tree-hopper would pro- portionally indicate. It can on this account be par- tially examined without a microscope, being, in some of the larger species, no less than five lines! i"^ length. The ovipositor or auger [tarih'e) as Reaumur calls it, is lodged in a sheath which hes in a groove of the terminating ring of the belly. It requires 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 throughout except at the point, - Cuntu querulcp. rumpent arbusta cicadas. Geoig. iii. 328. t A line is about the twelfth pnit of an inch. TREE-HOPPER. 149 where it is somewhat enlarged and angular, and on both sides finely indented with teeth. A more mi- nute 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 on each side, appear strong, and arranged with great symmetry, increasing in fineness towards the point, where there are three or four very small ones, beside the nine that are more obvious. The magnifier also shews that the instrument itself, which appeared sim- ple to the naked eye, is in fact composed of three difierent pieces, two exterior armed with the teeth before-mentioned, denominated by Rtaumur 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 origui of the ovipositor, it may be presumed that those mus- cles are destined for producmg 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 ex tent. The contrivance by which those three pieces are held united, while at the same time the two files can be easily put in motion, are similar to some of our own mechanical inventions, witli this difference, that no human workman could construct an instrument of this description so small, fine, exquisitely poHshed, and fitting so exactly. We should have been apt to VOL. IV. 13* 150 INSECT ARCHITECTURE. form the grooves 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. Reaumur discovered that the best manner of showing the play of this extraordinary instrument is to cut it oft' with a pair of scissors near its origin, and then, takmg it between the thumb and the finger at the point of section, work it gently to put the files in motion. Oviposit-irs, u-itli fili.s, cf T, Sinfed. Beside the muscles necessary for the niovcnTent 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 ceniral jtiece. as is shewn in the lower figure. M. Pontedera, wlio studied the economy of the tree-hoppers with some care, was anxious to sec the TREE-HOPPERS. 151 insect itself make use of the ovipositor in forming grooves in wood, but found that it was so shy eind easily alarmed, that it took to flight whenever he approached; a circumstance of which Rraumur takes advantage, to soothe his regret that the insects were not indigenous in his neighbourhood. But of their workmanship when completed, he had several speci- mens sent to him from Province and Languedoc by the Marquis de Caumont. The gall-flies, when about to deposit their eggs, select growing plants and trees; but the tree-hoppers on the contrary, make choice of dead, dried branches lor the mother seems to be aware that moisture %vould injure her progeny. The branch, commonly a small one, in which eggs have been deposited, may be recognised by being covered with little oblong elevations caused by small splinters of the wood, de- tached at one end, but lefl flxed 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 /:-. -: ;--^,," •./ i ■..-..■■,■,.■. ..,iu ..,u raised. 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 at 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 capable of protecting them from the wea- ther; but M. Reaumur thinks this only a fancy, as 152 INSECT ARCHITECTURE. out of a great number which he examined, he could discover nothing of the kind. Neither is such a pro- tection wanted; for the woody splinters above men- tioned furnish a very good covermg. The grubs hatched from these eggs (of which, M, Pontedera says, one female will deposit fiom 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 chrysahdes, but into active nymphs, remarkable for their fore limbs, which are thick, strong, and furnished with prongs for digging; and when we are told by Dr Le Fevre, 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 conformation 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 Valisnieri, an eminent Italian naturalist, in a fore-winged fly, most appro- priately denominated by M. Reaumur the saxi'-JJy (Tenthredo), of which many sorts are indigenous to Great Britain. The grubs from which those flies originate are indeed but two well known, as they fre- quently strip oin- rose, gooseberry, raspberry, and red currant trees of their leaves, and are no less destruc- tive to birch, alder and willows; while turnips and wheat suffer still more seriously by their ravages. These grubs may readily be distinguished from the cater- pillars of moths and butterflies, by having from six- teen to twenty-eiglit feet, by which they usually hang to the leaf they feed on, while they coil up the hinder part of their body in a spiral ring. The perfect flies are distinguished by four transparent ^vings; and SAW-FLIES. 153 some of the most common have a flat body of a yellow or orange colour, while the head and shoulders are black. In order to see the ovipositor to which we shall for the present turn our chief attention, a female saw- fly must be taken, and her belly gently pressed, when a narrow slit will be observed to open at some dis- tance from the anus, and a short, pointed, and some- what curved body, of a brown colour and horny sub- stance, will be protruded. The curved plates which tbrm 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 in- strument, however, and its singular structure, cannot be well understood without the aid of a microscope. a. Ovipositor oj' Saw-fly, protruded from its Sheath, magniefid. The instrument thus brought into view, is a very finely contrived saw, made of horn, and adapted for penetrating branches and other parts of plants where the eggs are to be deposited. The ovipo- sitor saw of the insect is much more complicated than any of those employed by our carpenters. The teeth of our saws are formed in a line, but in such a manner as to cut in two lines parallel to, and at a small distance from each other. This is effected by slightly bending the points of the alternative teeth right and left, so that one half of the whole teeth 154 INSECT ARCHITECTURE. stand a little to the right , and the other half a httle 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 instru- ment. It will follow, that in proportion to the thin- ness of a saw there will be the less destruction of wood which may be sawed. When cabinet-makers have to divide valuable wood into very 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 the 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 instru- ment, on the contrary, is towards the point some- what concave, similar to a scythe, while towards the base it becomes a little convex, the whole edge being nearly the shape of an Italic/. Ovipositor-saw o/Saw-Jly, with rasps shew SAW-FLIES. 155 The ovipositor-saw of the fly is put in motion in the same way as a carpenter's hand-saw, supposing the tendons attached to its base to form the handle, and the muscles which put it in motion to be the hand of the carpenter. But the carpenter 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 un- known to our mechanics ; for two or three are some- times fixed in the same frame. These, however, not only all move upwards and downwards simultane- ously, but cut the wood in different places; while the two saws of the ovipositor work in the same cut, and, consequently, though the teeth are extremely fine, the effect is similar to a saw with a wide 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 approach the point which the form of the saws require. Ac- cording 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, Vv'hieh 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 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, * Reaumur, Mem. des Insectes, v. p. iii. 156 INSECT ARCHITECTURE. these two properties have never been combined in any of the tools of our carpenters. The rasping part of the ovipositor, hoAvever, is not constructed like our rasps, with short teeth thickly studded toge- ther, but has teeth almost as long as those of the saw, and placed contiguous 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 inicroscope. Portion of Sam-Ji'/s comh-toolhcd rasp, and suic. When a female saw-fly has selected the branch of a rose-tree, or any other, m 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 penetrate the bark or wood. She ifiain- tains this recurved position so long as she works m deepening the groove; but when she has attained the depth required, she unbends her body mto 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 with- drawn 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 Avith soap, is dropped over the egg, either for the purpose of glue- ing it in its place, or sheathing it from the action of the juices of the tree. She proceeds in the same manner in sawmg out a second groove, and so on in SAW-FLIES. 157 succession till she has deposited all her eggs, some- times 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 shitis to another, or to a ditFerent part of the branch, when she is either scared or finds it un- suitable. She commonly, also, takes more than one day to the work, notwithstanding 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 finished, 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 the part becomes first brown and then black, while it also becomes more and more elevated. This increased elevation is not owing to the gro^vlh 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 larger. This groAvth 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 continues to increase, it raises the bark more and more, and consequently widens, at the same time, the slit at the entrance; so that, when 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 disturbing one another by their developement. 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 of making a groove for each egg, like the voi,. IV 14 158 INSECT ARCHITECTURE. preceding, she forms a large single groove, sufficient for about two dozen eggs. These eggs are all ar- ranged in pairs, forming two straight Unes parallel to the sides of the branch. The eggs, however, though thus deposited in a common groove, are carefully kept 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 each egg of a row a thin partition of wood is left, forming a shallow cell. Nest of eggs of Saw-Jly, in rose tree. The edges of this groove, it will be obvious, must be farther apart than those which only contain a single egg, and, in fact, the whole is open to inspec- tion; 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 pre- ceding. Chapter VIII. Leaf-rolling Caterpillars. The labours of those 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, durnig the hrst 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 caterpillar from its enemies, and a store of food for its subsistence, while it remains shut up in its prison. But the insect only devours the inner folds. The art which these caterpillars exercise, although called into action but once, perhaps, in their lives, is perfect. They accomplish their purpose with a mechanical skill, which is re- markable for its simplicity and unerring succe-^s. The art of rolling leaves into a secure and immovable 160 INSECT ARCHITECTURE. cell may not appear very difficult; — nor woald it be so if the caterpillars had fingers, cr anv parts which were equivalent to those delicate and admirable natural instruments with which man accomplishes his most elaborate works. And yet the human finsfers could not roll a rocket-case of paper more regularlv than the caterpillar rolls his house of leaves. A leaf is not a very easv substance to roU. In some trees it is very brittle. It has also a natural elasticitv, — a disposition to spring back if it be bent, — which is caused by the continuity of its threads, or 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 manv weeks, under everv varietv of temperature. We will examine, in detail, how these httle leaf-rollers accomplish their task. One of the most common as well as the most simple fabrics constructed by caterpillars, may be dis- covered during summer on almost everv kind of bush and tree. We shall take as examples those which are found on the hlac, and on the oak. A small but ver}- pretty chocolate coloured moth, A Lilac tree Moth. (Lazotania Rtheana, Stophens ?J abundant in ever}- garden, but not readily seen from its frequently alightmg on the ground which is so nearly of its own colour, deposits its eggs on the leaves of the lilac, and of some other trees, appro- priating a leaf to each egg. As soon as the cater- pillar is hatched, it begins to secure itself from birds and predatory insects by rolhng up the lilac leaf into CATERPILLARS. 161 the form of a galleiy, where it may feed in safety. We 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 the other, or from the edge to the mid-rib. Then going to the middle of the space, he shortened .the threads t»y bending them with his feet, and conse- quently pulled the edges of the leaves into a circular form; and he retained them in that position by glue- ing 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 farther advanced, they unite the two edges together in their whole extent, with the exception of a small opening at one end, by which an exit may be made in case of need. Nest of a Lilac-leaf Roller. Another species of caterpillar closely alHed 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 this form more securely, it is VOL. IV. 14* 162 INSECT ARCHITECTURE. 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 Nest of Lilac-tree Rollen- Another species of moth allied to the (wo pre- ceding, is of a pretty green colour, and lays its eggs Small s^-ecn Oak-moth. (Tortrix Viridana.) upon the leaves of the oak This caterpillar folds them up in a similar manner, but with this difference, that it works on the under surface of the leaf, pulling the edge downwards and backwards, instead of for- wards and upwards. This species is very abundant, CATERPILLARS. 163 JYests of oal-leaf rolling Caterpillars. and may readily be found as soon as the leaves ex- pand. In June, when the perfect insect has ap- peared, by beating a branch 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 spring, in little oval or circular patches of a green colour. The grub makes its appearance with the first opening of the leaves of whose structure in the half-expanded state it takes advantage to construct its summer tent. It is not, like some of the other leaf-rollers, contented 164 INSECT ARCHITECTURE. with a single leaf, but weaves together as many as there are in the bud where it may chance to have been hatched, binding their 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 inhabi- tant in the mean while banquets securely on the par- titions of its tent, eating door-ways from one apart- ment into another, through which it can escape in case of danger or disturbance. The leafits of the rose, it may be remarked, expand in nearly the same manner as a fan, and the opera- tions 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 leafits, but by means of its silken cords unites all which spring from the same bud into a rain-proof canopy, under 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 proceed- ings of the grub are the same, but it cannot unite the plaits so smoothly as in the case of the rose leafits, and it requires more labour also, as the nerv- ures being stiff", demand a greater etfort 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. This is well exemplified in one of the commonist of our leaf-rolling caterpillars, which may be found as early as February on the leaves of the nettle and the white archangel (Lamium albitm.) 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 leat-stalk, partly bending the edges inwards, and covering in the interval with a silken CATERPILLARS. 165 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 nettle leaf-rolling Caterpillar. We have watched this little architect begin and fitiish his tent upon a nettle in our study, the whole opera- tion taking more than half an hour.* He began by walking over the plant in all directions, examining the leaves severally, as if to ascertain which was best titted for his purpose l3y 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 with the pro-legs of his tail; then stretching his head to the edge of the leaf, he fixed a series of parallel cables between it and the mid-rib, with another series crossing these at an acute angle. The position in which he worked was most remarkable, 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 drawmg them into the form of the curve, shortened them, and conse- quently pulled the edge of the leaf down towards the mid-rib. The weight of his body was not, however, the only power which he employed; for, using the anaj pro-legs as a point of support, he exerted the * J. R. 166 INSECT ARCHITECTURE. whole muscles of his body to shorten his threads, and pull down the edge of the leaf When he had drawn the threads as tight as he could, he held them till ho spun fresh ones of sufficient strength to retain the leaf in the bent position into which he had pulled it. He then left the first 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 for his habitation. This was the first part of the architecture. 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 canvass, and are pegged into the ground. Un- willing to trust the exposure of his whole body on the outside, lest he should be seized by the first sand-wasp {odynerus) or sparrow which might descry him, he now withdrew to complete the interned portion of his dwelling, where the threads were hang- ing loose and disorderly. 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 spin his new threads so as to leave the loose ones on the outside, and make his apartment smooth £ind neat. When he again reached the opposite end, he constructed there also a similar series of cables on the outside, and then withdrew to give some final touches to the interior. It is said by Kirby and Spence,* that when these * Introd. vol. i. p. 457, CATERPILLARS. 167 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 observed the circumstance, though we have witnessed the 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 oper- ation 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.* A species of leaf-roller, of the most diminutive size, merits particular mention, although it is not remarkable jn 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 of this little cone the caterpillar 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 entirf ly detach this segment. It rolls it up very gra- dually, by attacliing threads of silk to the plane sur- face cf the leaf, as we have before seen; and then, having cut in a different direction, sets the cone upright, 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 be readily seen, is a somewhat complicated effort of mechanical skill. It has been minutely described by M. Reaumur; but the following representation ♦ J. R. 168 INSECT ARCHITECTURE. will perhaps make the process clearer than a more detailed account. Leaf-rolling Caterpillars of the Sorrel. This caterpillar, like those of which we have already spoken, devours all the interior of the roller. It weaves, also, in the interior, a small and thin co- coon of white silk, the tissue of which is made com- pact and close. It is then transformed into a chry- salis. The caterpillars of two of our largest and hand- somest butterflies, the Painted Lady ( Cynlhia cardui, Stephens), and the Admirable, or Mdcrman of the London fly-fanciers (Vanessa atahmia), are also leaf- rollers. The first selects the leaves of the great spear- thistle, and sometimes those of the stemless, or star- thistle, which might be supposed rather diflicult to bend; but the caterpillar is four times as large and strong as those which we have been liithcrto de- scribing. In some seasons it is ))lcntiful; in others it is rarely to be met \\ith: hut the Admirable is seldom scarce in any part oi" the country; and by CATERPILLARS. 169 examining the leaves of nettles which appear folded edge to edge, in July and August, the caterpillar may be readily found. Ntsts of ihe Ihspcria MalvcK, with CuterpiUar, C/irysalis, and Butterflies-' .Another butterfly {Hesperia inalvce) 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, pecuUarly different 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 VOL. IV. 15 170 INSECT ARCHITECTURE. joins it, indeed, so completely round and round, that it has somewhat the resemblance of an egg. Within this green cell it hes 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 par- cels of leaves, we know none so well contrived as those which are found upon willows and a species of osier. The long and narrow leaves of these plants are naturally adapted to be adjusted pa- rallel to each other; for this is the direction which ^'est rf Willnw-leaf Roll. CATERPILLARS. 171 they have at the end of each stalk, when they are not entirely developed. One kind of small smooth cater- pillar (Tortrix chlorana), 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 strik- ing in the mechanical manner in which it constructs them. It does precisely what we should do in a similar case: it winds a thread round those leaves which must be kept together, from a little above their termination to a very short distance from their ex- treme point; and as it finds the leaves almost con- stantly lying near each other, it has little difficulty in bringing them together, as is shewn in- the cut, a. The prettiest of these parcels are those which are made upon a kind of osier, the borders of whose leaves sometimes form columnar bundles before they are become developed. A section of these leaves has the appearance of fillagree work. — (See b, p. 170.) 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 of the leaves, by drawing them together in an inge- nious manner. M. Roesel* has given a tolerable representation of this nest, and of the caterpillar. The caterpillar is found in June ; and the moth (JVb- todmita ziczac) from May to July in the following year. — (See cut, p. 172.) Beside those caterpillars which live solitary in the folds of a leaf, there are others which associate, em- ploying their united powers to draw the leaves of the plants they feed upon into a covering for their com- mon protection. Among these we may mention the caterpillar of a small butterfly, -the plantain of Glan * Roesel. cl. ii., Pap. Nocturn., tab. xx., fig. 1, 2, 3, 4, 5, 6. 172 INSECT ARCHITECTURE. ville fritillary (Melitea cinxia), which is very scarce in this country. Ziczdc Caterpillar and Nest- Although a colony of these caterpillars is not nu- merous, seldom amounting to a hundred individuals, the place which they have selected is not hard to dis- cover. Their abode may be seen in the meadow in form of a tutt 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, in which the whole brood lives, eats, and undergoes the usual transformations. The shape ^of this tent, for CATERPILLARS. 173 the most part, approaches the pyramidal, though that depends much upon the natural growth of the her- bage which composes it. The interior is divided into compartments formed by the union of several small tents, as it were, to which others have been from time to time added according to the necessities of the com- munity. When they have devoured all the leaves, or at least those which are most tender and succulent, they abandon their first camp, and construct another contiguous to it under a tuft of fresh 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 purpose; but though they prefer this plant, they content them- selves with grass if it is not to be procured. When they are about to cast their skins, but par- ticularly when they perceive the approach of winter, they construct a more durable apartment in the inte- rior of their principal tent. The ordinary web is thin and semi-transparent, permitting the leaves to be seen through it; but their winter canvass, if we may call it so, is thick, strong, and quite opaque, forming a sort of circular hall without any partition, where the whole community lie coiled up 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. R'aumur found upon trial, that it was not only the caterpillars hatched from the eggs of the same mother which would unite in constructing the com- mon tent ; for different broods, when put together, worked in the same social and harmonious manner. We ourselves ascertained, during the present sum- mer, (1829,) that this principle of sociality is not confined to the same species, nor even to the same VOL. IV. 15* 174 INSECT ARCHITECTURE. genus. The experiment which we tried was to con- fine two broods of different species to the same brancli by placing it in a glass of water to prevent their escape. The caterpillars which we experimented on were several broods of the brown-tail moth {Porthesia auriflua), and the lackey {CUsiocampa 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 lackey's encountered the brown-tails they mani- fested no alarm or uneasiness, but passed over the backs of one another as if tliey had made only a por- tion of the branch. In none of their operations did they seem to be subject to any discipline, each indi- vidual 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. "f The design of the caterpillars in rolling up the leaves is not only to conceal themselves from birds and predatory insects, but also to protect them- selves 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 conceal- ment, however, though it appear to be cunningly contrived and skillfully executed, is not always suc- cessful, their enemies often discovering their hiding place. We happened to see a remarkable instance of this last summer (1 828), in the case of one of the lilac caterpillars which had changed into a chrysalis within the closely folded leaf A small cuckoo-fly, aware, it should seem, of the very spot where the chrysalis lay within the leaf, was seen boring through * See p. 1 1 .'■.. I .T. H . CATERPILLARS. 175 it with her ovipositor, and introducing her eggs through 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 chry- salis, and finally changed into pupae in a case of yel~ low silk, and into perfect insects like their parent.* * J. R. Chapter IX. Insects forming Habitations of detached Leaves. The habitations of the insects which we have just described consist of growing leaves, bent, rolled, or pressed together, and fixed in their positions by silken threads. But there are other habitations of a similar kind which are constructed by cutting out and detaching a whole leaf, or a portion of a leaf We have already seen how dexterously the upholsterer- bees cut out small parts of leaves and petals with their mandibles, and fit them into their cells. Some of the caterpillars do not exhibit quite so much neat- ness 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, m the delicate minutiae 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. Rv'au- mur never observed to be in a dry state even during summer. This marsh is surrounded with very lofty oaks, and abounds with pondweed, the water plant named by botanists polamogeton. The shining leaves of this plant, 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. Reaumur observed, beneath one of the PONDWEED TENT-MAKER. IT? first which he exainhied, 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. Breaking the threads, he raised up one of the ends, and saw a cavity in which a caterpillar (^Hijdrocampa Potamogata) was lodged. An indefatigable ob- server, such as M. R'aumur, would naturally follov/ up this discovery; and he has accordingly given us a memoir of the pondweed tent-maker, distinguished by his usual minute accuracy. In order to make a new cocoon, the caterpillar fastens itself on the underside of a leaf of the Potu- mogeton. With its mandibles it pierces some part of this leaf, and atterwards gradually gnaws a curve line, marking the form of the piece which it wishes to detach. When the caterpillar has cut oft", 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 mate- rials requisite for making a tent. It takes hold of this piece by its mandibles, and conveys it to the situation on the underside of its own, or another leaf, whichever is found most appropriate. It is there disposed, in such a manner, that the underpart of the patch — the side which Avas the underpart of the entire leaf — is turned towards the underpart of the new leaf, so that the inner walls of the cocoon are always made by the underpart of two portions of leaf The leaves of the potamogeton are a little con- cave on the underside; and thus the caterpillar pro- duces a hollow cell, though the rims are united. The caterpillar secures the leaf in its position by threads of white silk. It then weaves a cocoon in the cavity 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 trans- formed into a chrysalis. In this cocoon of silk no 178 INSECT ARCHITECTURE. point touches the water; whilst the cocoon of leaves, lined with silk, has been constructed underneath the water. This fact proves that the caterpillar has a particular art by which it repels the water from be- tween the leaves. When a caterpillar, which has thus conveyed, and disposed a patch of leaf against another leaf, is not ready to be transformed into a chrysalis, it applies itself to make a cocoon — a habitation which it may carry everywhere about with it. It begins by slightly fixing the piece against the whole leaf, leaving inter- vals all round, between the piece and leaf, at which it may project its head. The piece which it has 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 caterpillar is inclined to change its situation, it draws itself forward by means of its scaly limbs rivetted upon the leaf The mem- branous limbs which are rivetted against the inner sides of the cocoon, oblige it to follow the anterior part of the body, as it advances. The caterpillar, also, puts its head out of the cocoon every time it desires to qat. There is found on the common chick-weed ( Sfel- laria media) towards the end of July, a middle-sized smooth green caterpillar, having three brown spots bordered with white on the back, and six legs and ten pro-legs, whose architecture is worthy of obser- vation. When it is about to go into chrysalis, to- wards the beginning of August, it gnaws off, one by one, a number of the leaves and sm.aller twigs of the chick-weed, and adjusts them into an oval cocoon, somewhat rough and unfinished, externally, but smooth, uniform, and finely tapestried with white silk within. Here it undergoes its transformations CVPRESS-SPURGE CATERPILLAR. 179 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 band on each of its four wings below. It is also furnished with a sort of tail. On the cypress spurge (Euphorbia cyparissias), a native woodland plant, but not of very common occurrence, may be found, towards the end of Octo- ber, a caterpillar of a middle size, sparely tufted with hair, 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. Cypres.j-Spicrge Caterpillar -( Acronycta Eupkrcsia: ?)—u:ith a Cccoon, mi a branch. A caterpillar which builds a very similar cocoon to the last mentioned, may be found upon a more common plant — the yellow snap-dragon or toad-flax 180 INSECT ARCHITECTURE. (Aniirrhinum linaria) — which is to be seen in almost every hedge. It is somewhat sliaped Uke a leech, is ot'a middle size, and the prevailing colour pearl-grey, but striped with yellow and black. It spuis 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 with great symmetry and neatness. The moth appears in tlie following June. It is worthy of remark, as one of the most striking instances of instinctive foresight, that the caterpillars Avhich 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.* This is a remarkable example of the Instinct which leads these little creatures to act with a foresight in many cases much clearer than the dictates of human prudence. In the examples be- fore us, the instinct is more delicate and complex than that which directs other animals to provide a burrow for their winter sleep. It is not unreasonable to suppose that the one caterpillar is aware, while it is building the cocoon, that the moth into which it is about to be changed will not be in a fit state to appear before the succeeding summer. The other, pursuing a similar course of thought, may feel that the moth will see the light in a few weeks. The comparative distances of time certainly appear most difficult to be understood by an insect; for, as far as we know; quadrupeds do not carry their intelligence io such extent. And yet in the solitary case of * J R CYPRESS-SPURGE CATERPILLAR. 181 provision for a future progeny, the instinct is in- variably subtle and extraordinary. What, for in- stance, is more remarkable than that the insect should always place her eggs where her progeny will find the food which is best suited to their nature ? In almost no case does the perfect insect eat that food, so that the parent cannot judge from her own habits. The Contriver of the mechanism by which insects work also directs the instinct by which they use their tools. It is exceedingly difficult, with our very hmited knowledge of the springs of action in the inferior animals, to determine the motives of their industry — that is, whether they see clearly the end and object of their arrangements. A human architect, in all his plans, has regard, according to the extent of his skill, to the combination of beauty and convenience; and in most cases he has adaptations peculiar to the cir- cumstances connected with the purpose of the struc- ture. In the erection of a common dwelling-house, for instance, one family requires many sleeping- rooms, another few — one wants its drawing-rooms in a suite, another detached. The architect knows all these wants, and provides for them. But all insects build their habitations upon the same general model, although they can slightly vary them according to circumstances. Thus, according as the uniformity, or the occasional adaptation of their work to particu- lar situations, has been most regarded by those who speculate upon their actions, they have been held to be wholly governed by instinct or by intelligence — have been called machines or free agents. There are difficulties in either conclusion; and the truth perhaps lies between the two opinions. Their actions may entirely result from their organization; they are cer- tainl}' in conformity with it. Those who would deny the animal all intelHgence, by which we mean a power, VOL. IV. 16 182 INSECT ARCHITECTURE. yesulting from selection, of deviating in small matters from a precise rule of action, are often materialists, who shut their eyes to the creating and preserving economy of Providence. But even this belief in the infallible results of organization does not necessarily imply the disbelief of a presiding Povi^er. " 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 dif- ferent operations which are the natural results of the economy of the animal should concur towards the same end. The creature is directed towards his ob- ject by an invisible hand; he executes with precision, and by one effort, those works which we so much admire; he appears to act as if he reasoned, to retuin 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 drives him on. He is but an instrument which cannot judge of each action, but is wound up by that adorable Intelli- gence, which has traced out for every insect its pro- per labours, as he has traced the orbit of each planet. When, therefore, I see an insect working at the construction of a nest, or a cocoon, I am im- pressed 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 rapoi), and are smooth and bluish. The material which they use in building their cocoons is * Contemplation de la Nature, part xv. chap. 38. MOSS-BUILDING CATERPILLAR. 183 composed of the leaves and branchlets of green 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 supposed 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. MoiS-Cill of Smalt Caterpillar (BryophVa Jxrla.) In May last (IS^g), 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. Reaumur.* The/ 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 cateqiillar of this sort ap- pears 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 * J. R. 184 INSECT ARCHITECTURE. builds an arched wall so as to form a chamber consi- derably larger than is usual with other architect ca- terpillars. 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 work. Yet it does not de- mand 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 measuring rule, and partly for a mould, or rather a block or centre to shape the walls by, curving itself round and round concentrically with the arch which it is builduig. 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 colour, we were thereby able to ascertain that there was not a particle of lichen em- ployed in the structure. The neatness mentioned by Reaumur, as remark- able in his moss-building caterpillars, is equally ob- servable in that which we have just described; for, on looking at the surface of the wall, it would be impos- sible for a person unacquainted with these structures to detect where 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 lose? no time in repairing the breach, b} piecing in bits of mortar and fragments of lichen, till we can scarcely distinguish the new por- tion from the old. Chapter X. tGaddis-Wornis and Carpenter-UarttTpillara. There is a very interesting class of grubs which Hve 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-ivorms, and to naturalists as the larvcB of the four-winged flies in the order Trichop- tera, 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 aper- ture sufficiently large for the inhabitant to put out its head and shoulders when it v/ishes to look about for Leaf neit of Cuddis Worms- food. Another employs pieces of reed cut into cou venient lengths, or of grass, straw, wood, &c., care- fully joining and cementing each piece to its fellow as the work proceeds ; and he frequently finishes tho Reed Nest of Caddh-JVo 16* 18fi INSECT ARCHITECTURE. whole by adding a broad piece longei- than the rest lo shade his door-way over-head, so that he may not be seen from above. A more laborious structm-e is reared by the grub of a beautiful caddis-fly (Phry- ganea), which weaves together a group of the leaves of aquatic plants into a roundish ball, and in the in- terior of this forms a cell for its abode. The fol- lowing figure from Roesel v.ill give a more precise notion of this structure than a lengthened description. J Another of thp>v j.quatic- architects make clioice of the tiny shells of young li-esh-water mussels and snails (Planorhis), to form a moveable grotto, and as these little shells are lor the most part inhabited, he keeps the poor animals close prisoners, and drags Hhell Nests ofCaddis-Wo CADDIS-WORMS. 187 them without mercy along with him. These grotto- buildiiig 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 of the hollow 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 per- forming this problem will appear to be considerable, if not insurmountable; 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 of the pro- Slonc Nisi of Cuhlis-n'oriii. blem, 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 progress when dragged along the bottom of the rivulet where it resides. The selection of the stones, indeed, may be accounted 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 purpose, it is probable that the grub makes choise of larger stones than it might otherwise want ; and therefore also it is that we frequently find a case composed of very small stones and sand, to which, Sand rfesi bnlanced wilh a Stone- 588 INSECT ARCHITECTURE. when nearly 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-ieorm balanced ^nth Straw/;. It is worthy of remark, that the cement, used in all these cases, is superior to pozzolana* in stand- ing water, in which it is indissoluble. The grubs themselves are also admirably adapted for their mode of hfe, 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 con- sequently less liable to injury than the protected por- tion, should it chance to be exposed. We have repeatedly tried experiments with the in- habitants of those aquatic tents, to ascertain their mode of buildmg. We have deprived them of their little houses, and furnished them with materials foi- constructing new ones, watching their proceedings from their laying the first stone or shell of the struc- ture. They work at the commencement in a very clumsy manner, attaching a great number of chips to whatever materials may be within their reach with loose threads of silk, and many of these they never use at all in their perfect building. They act, indeed, much like anunskilful workman trying his hand be- fore 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 them- * A cement prepared of volcanic earth, or lava. GOAT-MOTH. 189 selves 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.* Carpenter-Caterpillars. Insects, though sometimes actuated by an instinct apparently blind, unintelligent, or unknown to them- selves, manifest in other instances a remarkable adap- tation of means to ends. We have it in our power to exemplify this in a striking manner by the proceed- ings of the caterpillar of a goat-moth ( Cossus ligni- perda) which we kept till it underwent its final change. Caterpillar of Goat-Moth in a Willow Tree. 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 190 INSECT ARCHITECTURE. 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 body in a bent or somewhat coiled up position. On sawing off a portion of an old poplar in the winter of 1827, Ave found such a cell with a cater- pillar coiled up in it. ff inter JSest of the Goat Caterpillar- 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 broad-cloth, and equally warm, composed of the rasp- ings of the wood scooped 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 eat- ing; but upon being removed into a warm room and placed under a glass along with some pieces of woodj 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 lett it untouched, and made it the basis of the edifice it began to construct. It GOAT-MOTH. 191 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 protection 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 voraciously, 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 pre- vious 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 wood em- ployed; in the second, two pieces were placed in such a manner as to support each other, and beneath the angle thus formed, an oblong structure was made, composed, as before, of wood-raspings and silk, but much stronger in texture than the winter cell. In a few weeks (four, if we recollect right) the moth came forth.* ^tstof Goat-J>/o«A.— Figured ftrnn specimen, and raised toshow thePii/K/. » J. R. 192 INSECT ARCHITECTURE. * A wood-boring caterpillar, of a species of moth much rarer than the preceding (JEgeria asiliformis, Stephens), exhibits great ingenuity in construct- ing a cell for its metamorphosis. We observed above a dozen of them during this summer (1829) in the trunk of a poplar, one side of which had been stripped ot its bark. It was this portion of the trunk which all the caterpillars selected for their final retreat, not one having been observed where the tree was covered with bark. The inge- nuity of the little architect consisted in scooping its cell almost to the very surface of the wood, leaving only an exterior covering of unbroken wood, as thin as writing paper. Previous, therefore, to the chry- salis making its way through this feeble barrier, it could not have been suspected that an msect 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 move- able lid of a sort of brown wax.* 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 (Centra vinula). The caterpillar is produced from brown-coloured shining eggs, about the size of a pin's head, which are deposited — one, two, or more together — on the upper surface of a leaf. In the course of six or eight weeks (during which time it casts its skin thrice) it arrives at its full Eggs (f the Puss-Moth. * J. R. PUSS-MOTH. 193 growth, when it 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 during 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 ena- bled to give the details of the process. The puss, it may be remarked, does not depend for protection on the hole of a tree, or the shelter of an overhanging 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 pro- cured, 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 pro- cure.* With silk it first wove a thin web round the * It is justly remarked by Reaumur, that when caterpillars are left at liberty among their native plants, it is only by lucky chance they can be observed 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 doors, where they may be always under the eye of the naturalist. In such circumstances, however, we may be ignorant what building materials we ought to provide them with for their structures. A red caterpillar, with a few tufts of hair, which R'aumur found in July feeding upon the flower bunches of the nettle, and refusing to touch the leaves, began in a few days to prepare its cocoon, by gnawing the pa- per 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 R aumur found that it was likely to gnaw through the paper lid of the bos, 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 strncture, which it took VOL J v. 17 194 INSECT ARCHITECTURE. edges of the place which it marked out for its edi- fice; then it ran several threads in a sparse manner from side to side, and from end to end, but very irregularly in point of arrangement : these were in- tended for the skeleton or frame-work of the building. Rudiments of the Ce/l of the Puss-Moth. When the outline was finished, the next step was to strengthen each thread of silk, by adding several (sometimes 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 compression 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 the 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 pres- sure with the finger; but as soon as it became day to complete. The moth appeared four weeks after, of a brownish-black colour, mottled with white, or rather grey, in the manner of lace. Bonnet also mentions more than one instance in which he observed caterpillars making use of paper, when they could not procure other materials. PUSS-MOTH. 195 thoroughly dry, it was so hard that it could with difficulty be penetrated with the point of a penknife.* Ctll built by the Lnrva of the Piiss-JMoth. A question will here suggest itself to the curious inquirer, how the moth, which is not, like the cater- pillar, furnished with mandibles for gnawing, can find 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 at- tempted to follow, stuck by the way and died. On detaching the cell from the box, we found several others, which had not been able to get out, and had died in their cocoons."}" ^ Ichneumon (Ophion luteuni ) Ji^red from the one mentioned. ♦ J. R. + J. R. 196 INSECT ARCHITECTURE. Among the carpenter-grubs may be mentioned that of the purple capricorn-beetle ( Callidium viola- ceum,) of which th-e Rev Mr Kirby has given an interesting account in the fifth volume of the Lin- nean Transactions. This insect feeds principally on fir timber, which has been felled some time with- out 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 ori- ginally a native. The circumstance of this destruc- tive 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 all barked as soon as they were felled. The female is furnished, at the posterior extremity of her body, with a flat retractile tube, which she inserts between the bark and the wood, to the depth of about a quar- ter of an inch, and there deposits a single egg. By stripping off" the bark, it is easy to 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 fiom 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 sur- face; by this means its paths are rendered of con- siderable width. The bed of its paths exhibits, when closely examined, a curious appearance, occasioned by the gnawingsof itsjavvs, which excavate an infinity of little ramified canals. When the insect is about to assume its chrysalis state, it bores down obliquely OAK-BARK CATERPILLAR. 197 into the solid wood, to the depth sometimes of three inches, and seldom if ever less than two, forming holes nearly semi-cylindrical, and of exactly the form of the grub which inhabits them. At first 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, Avhich, in the act of chewing, apply to each other the whole of their inte- rior 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 per- fect insects gnaw their way out, which generally takes place betwixt the middle of May and the middle of June. These insects are supposed to fly only in the night, but during the day they may generally be found resting on the wood from which they were disclosed. The grubs are destitute of feet, pale, fold- ed, somewhat hairy, convex above, and divided into (thirteen segments. Their head is large and convex.* It would not be easy to find a more striking ex- ample of ingenuity than occurs in a small caterpillar which may be found in May, on the oak, and is sup- posed, by Kirby and Spence,to be that of the Pyralis strigulalis. It is of a whitish yellow colour, tinged with a shade of carnation, and studded with tufts of red hairs, on each segment, and two brown spots be- hind the head. It has fourteen feet, and the upper part of its body is much flatter than is common in caterpillars. When this ingenious little insect begms to form its cell, it selects a smooth young branch * Kirby in Linn. Trans, vol. v. p. 246, and Introd. ii. VOL. IV. 17* 198 INSECT ARCHrTECTURE. of the oak, near an offgoing 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 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 indeed never tra- vels farther for materials than the length of its own body. Upon the two longest sides of the triangular 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 little architect has completed these walls, which resemble very much the feathers of an arrow, Magnified Cells ofPyralis Strigidalis? a The walls before they are joined. &. Walls joined, but not closed as top. c. Side view of structure complete. OAK-BARK CATERPILLAR. 199 it proceeds to draw them together in a manner si- milar 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 re- quires 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 pro- ducing this appearance, the same principle being ex- tensively exemplified in numerous other instances. Chapter XL Earth-Mason Caterpillars. Many species of caterpillars are not only skilful in concealing 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 (Acheroniia afropos), 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 circumstance would not be sur- prising, 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 portion 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 unexpected, 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 per- haps 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 pupas: into the details of their operations it will not be so necessary for us to go, as into those which exhibit more ingenuity EARTH-MASON CATERPILLARS. 201 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, how- ever, when it is laid open, always exhibits a cavity, smooth, pohshed, and regular, in which the cocoon, or the chrysalis lies secure. (Fig. p. 202, b). The polish of the interior is precisely such as might be given to soft earth by moistening and kneading it with great care. But beside this, it is usually hned 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 T-'iexv of Nests of Earth-mason Caterpillars- One of the examples of this occurs in the ghost- moth {Hepialus humuli), 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 earthern 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 202 INSECT ARCHITECTURE, Nes/s, &c , of an Eavih-n Caterpillar^ earthern 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 in the earth, the cavity would be a long tube fitted exactly to its body {fig. c): it is essentially different. It does not indeed require very minute observation to perceive, that every grain of earth in the structure is united to the contiguous grains by threads of silk ; and that consequently, instead of the whole having been done at once, it must have required very considerable EARTH-MASON CATERPILLARS. 203 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 under- stand how this is performed, it may be not unin- teresting to follow the little mason from the begin- ning of his task. When one of those burrowing caterpillars has done feeding, it enters the earth, to the depth of several inches, till it finds mould fit for its pur- pose. Having nowhere to throw the earth which it may dig out, the only means in its power 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 Rtaumur well remarks, though the vault might endure the requisite time by the viscosity of the earth alone, were no change to take place in its humidity, yet, as a great number, are wanted to hold out fjr six, eight, and ten months, they require to be substantially built; a mere lining of silk, there- fore, would not be sufficient, and it becomes necessary to have the walls bound with 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 prepared a small pellet 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 completely overcome by JM. Rr'aiunur, in the instance 204 INSECT ARCHITECTURE. of the caterpillar of the water-betony moth ( Cu- cullia scrophularice, Schrauk), which he permitted to construct the greater part of its underground building, and then dug it up and broke a portion off from the end, leaving about a third part of the whole to be rebuilt. Those who are unacquainted with the instincts of insects might have supposed that, being disturbed by the demolition bt its walls, it would have left off 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 re- commencing its task for the purpose of repairing the disorder, which it accomplished in about four hours. At first it protruded its body almost entirely beyond the breach which had been made, to reconnoitre the exterior for building materials. Earth was put with- in its reach, of the same kind as it had previously used, and it was not long in selecting a grain adapted to its purpose, which it litted into the wall and secured with silk. It first enlarged the outside of the wall by the larger and coarser grains, and then selected finer for the interior. But before it closed the aper- ture, it collected a quantity of earth on the inside, wove a pretty thick network tapestry of silk over the part which remained open, and into the meshes of this, by pushing and pressing, it thrust grains of earth, securing them with silk till the whole was ren- dered opaque; and the further operations of the in- sect could no longer be watched, except that it was observed to keep in motion, finishing, no doubt, the silken tapestry of the interior of its little chamber. When it was completed M. Rraumur 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 ground. EARTH-MASON CATERPILLARS. 205 Earlh-Mason Cate,-pillui-'s Nests with the perfect Moth, 6fC. The grubs of several of the numerous species of may-fly i^Ephcintra) excavate burrows for themselves in soft earth, on the banks of rivers and canals, under VOL. IV 18 206 INSECT ARCHITECTURE. the level of the water, an operation well described by Scopoli, Swammerdam, and Rt'aumur. The excava- tions are always proportioned to the size of the in- habitant; and consequently, when it is young 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 water, so that the grub swims in its native element, and while it is se- cure 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. A'fiitj cf the Gruhs of Ephemera. A. The grab. B. Perforations in a river bank. C. One laid open to sliow tlie parallel structure. In the bank of the stream at Lee in Kent, we had occasion to take up an old v/illow stump, which, pre- vious to its being driven into the bank, had been per- forated in numerous places by the caterpillar of the EARTH-MASO.X CATERPILLARS. 207 goat-moth (^Cossus ligniperda). From having been driven amongst the moist clay, these perforations be- came filled with it, and the grubs of the ephemerae found them very suitable for their habitation; for the wood supplied a moie 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 v.ere full grow n grubs.* iNtifi 'J hj h 1 'la 111 7u)lcs ofCcssus. The architecture of the grub of a pretty genus of beetles, known to entomologists by the name of Ci- cindela, is pecuharly interesting. It Avas first made known by the eminent French naturalists, Geoffroy, Desmarest, and Latreille. This grub, which may be met with during spring, and also in summer and autumn, in sandy places, is long, cylindric, soft, whitish, and furnished with six brown scaly feet. The head is of a square fonn, Avith six or eight eyes, and ver)^ 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 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 greater diameter than their body, and fur- nished with a perpendicular entrance. In construct- * J. R. :208 INSECT ARCHITECTURE. ing this, the grub first clears away the particles of earth and sand by placing them on its broad trape- zoidal head, and carrying the load in this manner be- yond the area of the excavation. When it gets deeper down, it climbs gradually up to the surface with simi- lar 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 in- sect 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 aban- dons the task altogether, and begins anew in another situation. When it has succeeded in forming a com- plete 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 aperture of the excavation, and is on a level with the soil. In this position, the grub remams immoveable, with jaws expanded, and ready to seize and devour every insect which may wander within its reach, par- ticularly 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 cir- cumstance which renders it not a little difficult to discover the grub. The method adopted by the French naturalists 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 hke one of the caterpillars of the geo- metric 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 THE ANT-LION 209 Cicindela uses the excavation just described for the purpose of a trap or pitfall, any further than that it can more effectually secure its prey by tumbling them down into it; but there are other species of grubs which construct pitfalls for the express purpose of traps. Among these is the larva of a fly {Rhagio 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 depth, by throwing out the earth obhquely on all sides; and when its trap is finished, it stretches it- self along the bottom, remaining stiff and motionless, 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, wreathes 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 after it jets of sand and earth, with astonishing rapidity and force, and not unfi'e- quently succeeds in again precipitating it to the bottom of its trap. The Ant-Lk The observations of the continental naturalists have made known to us a pitfall constructed by an insect, the details of whose ojjerations are exceed- ingly curious — we refer to tl>e grub of the ant-lion (Mijrmeleon 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 Swit- VOL. IV. 18* 2lO INSECT ARCHITECTURE. zerlanc], it is probable it may yet be discovered m some spot hitherto unexplored, and if so, it will well reward the research of the curious. The ant-lion grub being of a grey colour, and hav- ing its body composed of rmgs, is not unlike a wood- louse (Oniscus), though it is larger, more triangular, 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 masticating, but are perforated and tubular, for the purpose of suck- ing the juices of ants upon which it feeds. Vallisnieii was, therefore, mistaken, as Reaumur well remarks, when he supposed that he had discovered its mouth. Its habits require 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 foiloM^ 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 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 suffi- cient footing to effect their escape. When the pit- fall is intended to be small, it only thrusts its body backwards into the sand as far as it can, throwing out at intervals the particles which fall in upon it, till it is rendered of the requisite depth. By shutting up one of these grubs in a box with THE ANT-L10.\ -ill A:d-Lion mngnificd, -u-ith and (mother begun. ,S p-rf.ct loose sand, it has been repeatedly observed con- structing its trap of various dimensions, from one to three inches in diameter, according to circumstances. When it intends to make one of considerable diame ter, it proceeds as methodically as the most skil- ful architect or engineer amongst ourselves. It first examines the nature of the soil, whether it be sufficiently dry and fine for its purpose, and if so, it begins by tracing out a circle, where the mouth of its funnel-trap is intended to be. Having thus marked the limits of its pit, it proceeds to scoop out the interior. Getting within the circle, and using one of its legs as a shovel, it places there- with a load of sand on the flat part of its head, and it throws tiie whole with a jerk some inches beyond, the circle. It is worthy of remark that it only uses 212 INSECT ARCHITECTURE. one leg in this operation — the one, namely, which is nearest the centre of the circle. Were it to employ the others in digging away the sand, it would en- croach upon the regularity of its plan. Working with great industry and adroitness in the manner we have just described, it quickly makes the round of its circle, and as its works backwards it soon arrives at the point where it had commenced. Instead, however, of proceeding from this point in the same direction as before, it wheels about and works a •ound in the contrary direction, and in this way it etvoids throwing all the fatigue of the labour on one leg, alternating them every round of the circle. Ant-Liofi's Pitfalls, in an experiment ing-box. Were there nothing to scoop out but sand or loose earth, the little engineer would have only to repeat the operations we have described, till it had completed the whole. But it frequently happens in the course of its labours, sometimes even when they are near a close, that it will meet with a stone of some size which would, if suffered to remain, injure materially the perfection of its trap. But such obstacles as this do not prevent the insect from proceeding : on the con- trary, it redoubles its assiduity to remove the ob- struction, as M. Bonnet repeatedly witnessed. If the stone be smal, it can manage to jerk it out in the £ame manner as the sand; but when it is two or THE ANT-LION. 213 three times larger and heavier than its own body, it must have recourse to other means of removal. The larger stones it usually leaves till the last, and when it has removed all the sand whicn it intends, it then proceeds to try what it can do with the less manage- able 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 ba- lanced on its back, by an alternate motion of the rings composing its body. When it has succeeded in adjusting the stone, it crawls up the side of the pit with great care and deposits its burden on the out- side 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 slope of loose sand which is ready to give way at every 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 impossible to suc- ceed, that it abandons the design and commences another pit in a fresh situation. When it succeeds in getting a stone beyond the line of its circle, it is not contented with letting it rest there; but to prevent it from again rolling in, it goes on to push it to a con- siderable distance. The pitfall, when finished, is usually about three inches in diameter at the top, about two inches deep, and gradually contracting into a point in the manner of a cone or funnel. In the bottom of this pit the ant-hon stations itself to watch for its prey. Should an ant or any other insect wander within the verge of the fiinnel, it can scarcely fail to dislodge and roll down some particles of sand, which will give notice to the 214 INSECT ARCHITECTURE, ant-lion below to be on the alert. In order to secure the prey, Reaumur, Bonnet, and others have observed the ingenious insect throw up showers of sand by jerking it from his head in quick succession, till the luckless ant is precipitated within reach of the jaws of its concealed enemy. It 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. Its next care is to mount the sides of the pitfall and re- pair any damage it may have suffered; and when this is accomplished, it again buries itself among the sand at the bottom, leavmg nothing but its jaws above the surface, ready to seize the next victim. When it is about to change into a pupa, it pro- ceeds in nearly the same manner as the caterpillar of the water-betony moth {Cucullia scrophularioi) . 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. Vv^ithin this it undergoes its transformation into a pupa^ and in due time, it emerges in form of a four-winged fly, closely resem- bling the dragon-flies {Lib ell idee,), vulgarly and erro- neously 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 de- struction and of escape.' As the larger quadrupeds of prey are provided with a most ingenious machi- nery for preying on the weaker, so are these furnished •vvith the most admirable powers of evading their destroyers. In the economy of msects, we constantly observe, that the means of defence, not only of the individual creatures, but of their larvfc and pupae, against the 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 ha^e the greatest THE ANT-LIOiV. 215 number of enemies. Bradley, an English naturalist, has calculated that two sparrows carry, in the course of a week, above three 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 vv'hich 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 larvse are produced, in comparison with the number which pass into the pupa state; and how many pupte perish before they become perfect insects! Every garden is covered with cater- pillars; and yet how few moths and butterflies, com- paratively, are seen, even in the most sunny season! Insects which lay tew eggs are, commonly, most remarkable in their contrivances for their preserva- tion. The dangers to which insect hfe is exposed are manifold; and therefore are the contrivances for' its preservation of the most perfect kind, and inva- riably adapted to the peculiar habits of each tribe. The same wisdom determines the food of every spe- cies 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 v/hich an insect employs for obtaining its food are curious, in proportion to the natural diffi- culties of its structure. The ant-lion is carnivorous. 216 INSECT ARCHITECTURE. but he has not the quickness of the spider, nor can he spread a net over a large surface, and issue from his citadel to seize a victim which he has caught in his outworks. He is therefore taught to dig a trap, where he sits, like the unwieldy giants of fable, wait- ing for some feeble one to cross his path. How laborious and patient are his operations — how un- certain 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 ex- istence, and continue that of his species. XII. Clothes-Motli, and other Tent-makiiig Caterpillars.— Leaf and Bark Miners. There are at least five different species of moths similar in manners and economy, the caterpillars of which leed upon animal substances, such as furs, woollen cloths, silk, leather, and, what to the natu- ralist is no less vexing, upon the specimens of insects and otiier animals preserved in his cabinet. The moths in question are of the family named Tinea by Entomologists, such as the tapestry moth ( Tinea ta- petzella), the LiiT moth (^Tinea pellionella), the wool moth (Tinea vestianella) , the ca,binet moth (Tinea Destructor, Stephen.s), &.c. The moths themselves are, in the winged state, small, and well fitted for making their way through the most minute hole or chink, so that it is scarcely possible to exclude them by the closeness of a ward- robe or a cabinet.* If they cannot effect an entrance when a drawer is out, or a door open, they will con- trive 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 rurninw to Pliny to learn this secret, we find him relating that stuff laid upon a coflSn will be ever after safo*^from I*^ 218 rNSECT ARCHITECTURE. moths; ia 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! Khasis again says, that cantha- rides suspended in a house drive away moths; and, he adds, that they will not touch anything wrapped in a lion's skin! — the poor little insects, says Reaumur sarcastically, being probably in bodily fear of so ter- rible an animal.* Such are the stories which fill the imagination even of philosophers, till real science en- tirely expels them. The effluvium of camphor or turpentine may some- times 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 up 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 cater- pillar, Bonnet says it tails into convulsions, becomes covered with livid blotches, and dies.f The mother insect takes care to deposit her eggs on or near such substances as she instinctively fore- knows will be best adapted for the food of the young, taking care to distribute them so that there may be a plentiful supply and enough of room for each. We have found, for example, some of those caterpillars feeding upon 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 effect of the cater- pillars more injurious, from their attacking many parts of a garment or a piece of stufi' at the same timej. When one of the caterpillars of this family issues * Reaumur, ¥cm. Hist. Insects, iii. 70. t Contemplation de la Nature, partxii. chap. x. note. i J. R. MOTH-CATERPILLARS. 219 from the egg, its first care is to provide itself with a domicile, which indeed seems no less indespensable to it than food; for, like all caterpillars that feed under cover, it will not eat while it remains vinpro- tected. 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 immediately aroimd 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 applies 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 con- structs 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. Reaumur, 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 struc- tures; and, at the moment of writing this, we turned out one from the carcase of an " old lady moth" {Mormo maiira, 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 * .\nimal Biography, vol. iii. p. 330, 3d ed. 220 INSECT ARCHITECTURE. the long hairs which surrounded it, as 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 founda- tion 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 caterpillars) it employed as a model and measure for regulating its operations. We remarked that it made choice 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 pur- pose, and the centre, indeed, where it turns, is always wider than the extremities. | When the caterpillar increases in length, it takes care to add to the length of its house, by working-in fresh hairs at 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. Reaumur cut off" with scissors a portion at each end, to compel * Bonnet, xi. p. 204, Kirby and Spence, Intro, i. 46J-. 5th ed. t J. R. MOTH-CATERPILLARS. 221 the insect to make up the deficiency. But the cater- pillar 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 prefers the former as less troublesome, and accomplishes its pur- pose " as dexterously," says Bonnet, " as any tailor, and sets to work precisely as we should do, slitting the case on the two opposite sides, and then adroitly in- serting between them two pieces of the requisite size. Cases, &c. of the Clothes-Moth (Tinea peUionellaJ—ap Caterillar feeding in a case, which has been lengthened by 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-Woths in their perfect state, when, as they cease to eat, they do no further injury. It does not, however, cut open the case from one end to the other at once; the sides would separate 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 sometiiues at the end, (Fig. c.) and then, after having filled up the fissure, proceeds to cut the remaming half; so that, in fact, four enlargements are made, and four sepai'ate pieces inserted. The colour of the case is always the same as that of the stuff from which it is taken. Thus, if VOL. IV. 19* 222 INSECT ARCHITECTURE. its original colour be blue, and the insect previously to enlarging 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 enlarge- ments in no precise order, but sometimes continuously, and sometimes opposite each other, indifferently. The same naturalist says he never knew one leave its 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 specimen of the ghost-moth (Htpialus Inumdi), where finding few suitable materials for building, it had recourse 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. Whether it took offence at our 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 bviilt a new apartment composed partly of cork as before, and partly of bits dipt out of the moth's wings. I We have seen these caterpillars form their habita- tions of 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 moschahis) or the large scolopendra of the West Indies, they find some difficulty in the building. When the structure is finished, the insect deems * Bonnet, vol. ix. p. 203. t J. R. TENT-MAKING CATERPILLARS. 223 itself secure to feed on the materials of the cloth or other animal matter within its reach, provided it is diy and free from fat or grease, which Reaumur found it would not touch. For building, it always selects the straightest and loqsegt pieces of wool, but for food it prefers the shortest and most compact; and to procure these it eats into the body of the stuff, 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 much worn. It must have been this circumstance which induced Bonnet to fancy (as we have already mentioned) that it cut 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. Tent-making Caterpillars. The caterpillars of a family of small moths ( Tinei- dce), 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 cursory observer, unac- quainted with their habits, they will appear more like the withered leaf scales of the tree, thrown off 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 in- habited 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 tho colour of a withered 224 INSECT ARCHITECTURE, leaf is not surprising ; for they are actually composed of a piece of leaf; not, however, cut out from the whole thickness, but artfully separated from the upper layer, as a person might separate one of the leaves of paper from a sheet of pasteboard. A caterpillar's tent upon a leaf of the elm. «, a the part of the leaf from which the tent has been cut out. 6, the tent itself. The tents of this class of caterpillars, which are found on the elm, the alder, and other trees with ser- rated leaves, are much in the shape of a minute gold-fish. They are convex on the back, where the indentations of the leaf out of which they have been cut add to the resemblance, by appearmg hke the dorsal fins of the fish. By depriving one of those caterpillars common on the hawtliorn of its tent, for the sake of experiment, we put it under the ne- cessity of making another; for, as Phny remarks of the clothes-moth, they will rather die of hunger than feed unprotected. When we placed it on 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.* For this purpose, it began to eat through one of the two outer membranes which compose the leaf and enclose the pulp (pareiichyma), some of which, also, it devoured, and then thrust the hinder part * J. R. tent-maki:>:g caterpillars. 225 of its body into the perforation. The cavity, how- ever, which it had tbrnied, being yet too small for its reception, it immediately resumed the task of niEdiing it larger. By continuing to gnaw into the pulp, beliveen the membranes of the leaf (for it took the greatest care not to puncture or injure the mem- branes 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 pro- ceedings. As the two membranes of leaf thus deprived of the enclosed pulp appeared white and transparent, every movement of the insect within could be distinctly seen; and it was not a little interesting to watch its ingenious operations while it was making its tent from the membranes prepared as we have just described. These, as Reaumur has remarked, 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 neat- ness and dexterity than this little workman does. As the caterpillar is furnished in its mandibles with an excellent pair of scissors, this may not appear to be a ditficult task; yet, when we examine the matter more minutely, we find that the peculiar shape of the two extremities requires different curvatures, and this, of course, renders the operation no less complex, as Reaumur subjoins, than the shaping of the pieces of cloth for a coat.* The insect, in fact, shapes the mem- branes slightly convex on one side and concave on the other, and at one end twice as large as at the other. In the instance which we observed, beginning at the larger end, it bent them gently on each side by press- ing them with its body thrown into a curve. We have not said it cuts, but sh(q)es its materials; for it must be obvious that if the insect had cut both the * Mem. Hist. Insect, iii. p. 106. 226 INSECT ARCHITECTURE. 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 secure them firmly 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, first 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 remain- ing support of its now finished tent, it took the pre- caution, before snipping it, to moor the whole to the uncut part of the leaf by a cable of its own 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.* a The caterpillar occupying the space it has eaten between the cuticle of the leaf, b 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. We have just discovered (Nov 4th, 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 ex- ^ J. R. STONE-MASON CATERPILLARS. 227 actly in the same manner as those which we have described, mining first between the two membranes of the leaf, and then uniting these and cutting out his tent. But the tent itself looks singular 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 hedgehog. 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.* Tents of Stone-mason Caterpillars. 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. JM. 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 uncommon on old walls. Reaumur observed them regularly for twenty years together, on the terrace-wall of the Tuileries at Paris; and they may be found in abundance in similar situ- ations in this country. This accurate observer refuted by experiment the notion of M. de la Voye, that the caterpillars 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, Reaumur 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 building with silk, till the cell acquii-ed the requisite magnitude, the whole operation taking about twenty-four hours of continued labour. M. de la Voye mentions small * J. R. ^^O INSECT ARCHITECTURE. granular bodies of a greenish colour, placed irregu- larly on the exterior of the structure, which he calls eggs; but we agree with Reaumur in thinking it more probable that they are small fragments of moss or Uchen intermixed with the stone: in fact, we have ascertained that they are so.* When these little architects prepare for their 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 inter- stice between the main entrance of the tent and the stone, but also weaving a close, thick curtain of the §ame material, to shut up the entire aperture. Tents and Caterpillars, both of their natural si:e ar.d magnified. It is usual for insects which form similar struc- tures, to issue, when they assume the winged state, from the broader end of their habitation ; but our little stone-mason proceeds in a difleront manner. It leaves open the apex of the cone fro;n the first, for the purpose of ejecting its exc ements, and latterJj- it enlarges this opening a little, to allow of a free exit when it acqvures wings; talcing care, however, to spin over it a canopy of silk, as a temporary pro- tection, which it CO Li afterwards burst through with- ^ J. R. STONE-MASON CATERPILLARS. 229 out difficulty. The moth itself is very much hke 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 numerous brood of small caterpillars, which employed grains of stone, not, hke the preceding, tor 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 hair. 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 Reaumur, on the brick wall of a gar- den at Blackheath, Kent.* They were so very small, however, and so like the lichen on the wall, that, had not our attention been previously directed to their 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, turbinated, conical form in which they had constructed their habitations, that we detected them. We tried the experiment above-mentioned, of ejecting one of the caterpillars from its tent, in order to watch its proceedings when constructing another; but probably its haste to procure shelter, or the arti- ficial circumstances into which it was thrown, influ- enced its operations, for it did not form so good a tent as the first, the texture of the walls being much slighter, while it was more rounded at the apex, and of course not so elegant. Reaumur found, in all his similar experiments, that the new structure equalled the old; but most 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, * J. R. VOL IV. 20 230 INSECT ARCHITECTURE. but it seems to be done with more hurry 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 circumstance in the operations of our little architect, which seems to have escaped the minute and accurate attention of Reaumur. When it commenced its structure, it was indispensable to lay a foundation 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 difliculty, and felt not a little interested in discovering how it would be got over. Accordingly, upon watching its move- ments with some attention, we were soon gratified to perceive that it used its own body as the pri- mary 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 hchen, till the wall was of the re- quired 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 sutEcient to admit its body. It ex- tended 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 through 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 of building a new one, by endeavouring to unhouse one of its neighbours. For this purpose, MUFF-MAKING CATERPILLARS. 231 it got upon the outside of the 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 aban- don his attempt. The instant, however, that the other vmmoored his tent and began to move about, the in- vader renewed his efforts to eject him, persevering in the struggle for several hours, 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 aper- ture 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 experhnent, 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 vege- table kingdom for the materials of his clothing. In all this, however, he is rivalled by the tiny inhabi- tants of the insect world, as we have already seen; and we are about now to give an additional instance of the art of a species of caterpillars which select a warmer material for their tents than even the cater- 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 232 INSECT ARCHITECTURE. short in the fibre to be advantageously employed in our manufactures. But the caterpillars to which we have alluded, find it well adapted for their habita- tions. The mutf-looking tent in which we find these in- sects, 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 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.* a, branch of the willow, with seed spike covered with cotton. 6, muff tents made of this cotton by c, the caterpillar. " RSaumur, iii. p. 130. MINING-CATERPILLARS. 233 An inquiring friend of Reaumur having found one of these insects floating about in its muff-tent upon water, conchided that they fed upon aquatic plants; but he was soon convinced that it had only been blown down by an accident, which must fre- quently happen, as willows so often hang over water. May it not be, that the buoyant materials of the tent were mtended to furnish the little inhabitant with a life-boat, ni which, when it chanced to be blown into the water, it might sail safely ashore and regain its native tree? Leaf-Mining Caterpillars. The process of mining between the two mem- branes of a leaf is carried on to more extent by mi- nute caterpillars allied to the tent-makers above described. The tent-maker never deserts his house, except when compelled, and therefore 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 (CurcuUonidce), some of two-winged flies (Dipfera), but the greater number are produced from a genus of minute moths (CEcophora, Latr.) 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 inch metallic colours which be- spangle their wings. Well may Bonnet call them "tiny miracles of nature," and regret that they are not en grand* There are tew plants or trees whose leaves may not, at some season of the year, be found mined by these * Bonnet, Contempl. de la Nature, Pait xii. VOL. IV. 20* 234 INSECT ARCHITECTURE. caterpillars, the track of whose progress appears on the upper surface in winding hnes. Let us take one of the most common of these for an example, — that of the rose-leaf, produced by the caterpillar of Ray's golden-silver spot (Argijromiges Rayella/? Curtis) of which we have just gathered above a dozen speci- mens from one rose tree,* Leaf of the Montkly-Rose (Rosa Indica) mined by Caterpillars of Argyromiges? It may be remarked, that the vnnding line is black, closely resembling the tortuous course of a river on a map, — beginning like a small brook, and gradually increasing in breadth as it proceeds. This representation of a river exhibits, besides, a narrow white valley on each side of it, increasing as it goes, till it terminates in a broad delta. The valley is the portion of the inner leaf from which the caterpillar has eaten the pulp (j^arenchyma), while the river itself has been formed by the liquid ejactamenta of the insect, the watery part becoming evaporated. In other species of miners, however, the dung is hard * J. R. MINING-CATERPILLARS. 235 and dry, and consequently these only exhibit the valley without the river. (See p. 237.) On looking at the back of the leaf, where the wind- ing 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 wan- dering 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 midrib 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 direction, sometimes woi-king 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 mme a tunnel to live in, and plenty of food, without touching the tvv'o external membranes. Let any one try with the nicest dissecting instruments 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 mi- nute 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 half the thickness of the pulp, 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, however, to prefer the foreign 236 INSECT ARCHITECTURE. monthly rose to any of our native species, and there are few trees of this where they may not be dis- covered. Tunnels, very analogous to the preceding, may be found upon the common bramble (Rubiis friUicosus)^ but 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. Leaf of the Dew-herry Bramble (Rubus ccesius) mined hy Caterpillars. The bramble-leaf miner seems also to diifer from that of the rose-leaf, by eating the pulp both from the upper and under surface, at least the track is equally distinct above and below; yet this may arise from the diflerent 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 minmg caterpillars may very frequently be found. It is, however, considerably MINING-CATERPILLARS. 237 different from the preceding, for there is no black trace — no river to the valley which it excavates: its ejectamenta, Ijeing small and solid, are seen, when the leaf is dried, in little black points like grains of sand. This miner, also, seems more partial than the pre- ceding to the midrib and its vicinity, in consequence of which its path is seldom so tortuous, and often appears at its extremity to terminate in an area, com- paratively extensive, arising from its recrossing its previous tracks.* N / / Leaf of the Primrose (Primula veris) mined htj a CaUifillar 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 pro- duced from this, whose upper wings, he says, " shone and glittered most gloriously with crescents of gold, silver, and brown, surrounded by borders oi delicate black." Another area miner which he found on the leaves of willows, as many as seventeen on one leaf, producing what appeared to be rusty spots, was metamorphosed into a very minute weevil {Curculio Rhinoc). He says he has been informed, * J. R. 238 INSECT ARCHITECTURE. that, in warm climates, worms are found in leaves an inch long, and adds, with great simplicity, " on these many fine experiments might have been made, if the inhabitants had not laboured 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 de- scribed above, uniting them and hning 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 (mon- ticules) 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 transforma- tions there, taking the precaution to mine a cell, not in the upper, but in the under surface of the leaf; others only shift to another portion of the leaf Social Leaf-Miners. 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 (Hijoscijamiis niger) which excavate a common area in concert — fiom four to eight forming a colony. These are very like flesh maggots, being larger than the common miners; the * Swanimerd. Book of Nature, vol. ii. p. 84. t Contempl. de la Nature, part xii. p. 197. MINING-CATERPILLARS. 239 leaves of this plant, from being thick and juicy, giving them space to work and plenty to eat. Most of tlie solitary leat-iiiiners either cannot or will not construct a new nunCj-'if ejected by an ex- perimenter from the old, as we have frequently proved; but this is not the case with the social miners of the henbane leaf Bonnet ejected one of these, and watched it with his glass till it com- menced a new tunnel, which it also enlarged with great expedition; and in order to verity the assertion of Rt'aumur, that they neither endeavour nor fear to meet one another, he introduced a second. Neither of them manifested any knowledge of the other's con- tiguity, 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 Caterpillars. A very ditferent 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 {Alhurnum). Some of these, though small, commit extensive ravages, as may rea- dily 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 typogvaphiis, Latr.), so called from its tracks resembling letters, amounted to above a milhon and a half in the Hartz forest. It appears there pe- riodically, and confines its ravages to the fir. This insect is said to have been found in the neighbour- hood of London. On taking off the bark of decaying poplars and willows, we have frequently met with the tracks of * Bonnet, Observ. sur les Insectes, vol. ii. p. 42-5. 240 INSECT ARCHITECTURE. a miner of this order, extending in tortuous path- ways, about a quarter of an inch broad, for several feet and even yards in length. The excavation is not circular, but a compressed oval, and crammed throughout with a dark-coloured substance like saw- dust— the excrement no doubt of the little miner, who is thereby protected from the attacks of siaphy- linidce, and other predaceous insects, from behind. But though we have tound a great number of these subcortical tracks, we have never discovered one of the miners, though they are very probably the grubs of the pretty musk-beetle {Cerambyx moscliatus) which is so abundant in the neighbourhood of the trees in question, that the very air in summer is per- fumed with their odour.* 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 de- stroys it. Capricorn B^eih, (drctvihyi. L:r,m