THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA PRESENTED BY PROF. CHARLES A. KOFOID AND MRS. PRUDENCE W. KOFOID ROMANCE OF THE INSECT WORLD NEST OK A TREE ANT. ROMANCE OF THE INSECT WORLD BY L. N. BADENOCH WITH ILLUSTRATIONS BY MARGARET J. D. BADENOCH AND OTHERS LARVA OF THE CADDIS-FLY (T richoptera). Eonfoon MACMILLAN AND CO. AND NEW YORK 1893 The Right of Translation and Reproduction is Reserved Copyright 1893 BY MACMILLAN AND Co. RICHARD CLAY AND SONS, LIMITED, LONDON AND BUNGAY V. b TO MY MOTHER A TOKEN OF AFFECTION ^345849 CONTENTS CHAPTER I. METAMORPHOSES OF INSECTS. Character of life-history of insects Metamorphoses of the butter- fly, beetles, &c. "Similarly changing" insects The two series Heteromorpha and Homomorpha True metamorphic stages considered in detail Egg Larva Shelters for ap- proaching change Meaning of pupa and other terms applied to stage Nature of condition in insects which undergo com- plete metamorphoses Signs of returning life Assumption of imago state Pseudo-imago Subsequent career Old idea of metamorphoses Modern theory Study of structures im- plicated External Modifications of internal organs Ex- planation of metamorphoses Apparent suddenness of changes Of the death-like period of quiescence CHAPTER II. FOOD OF INSECTS. Chief sources of food Almost limitless choice from vegetable world Death's Head Moth as a thief Animal feeders- Parasitic Hymenoptera and others Mighty business of insect- parasites upon insects Larva of the Tabby Another strange food of animal derivation Ants and their aphides Intimate connection of ants with other insects Usual restriction of CONTENTS PAGE insects to vegetable or animal diet Change of diet at different stages of life Need of nurses by the young of the Social Hymenoptera Livelihood without industry Slave makers Honey Ant Analogy between its economy and that of bee in storage of food Harvesting ants in the East, in Europe, in America Time of feeding Instruments of nutrition High adaptation of Lepidoptera to floral diet Means of procuring food Stratagem of ant-lion 34 CHAPTER III. HERMIT HOMES. Methods of formation of homes constitute remarkable phase of habits and economy of insects A home necessary by reason of nature of life of insects Habitations of solitary insects for their young Solitary bees Solitary wasps Galls Habita- tions of solitary larvoe for own use Homes of solitary architects being perfect insects for own use, and also for that of their young Trap-door and other spiders 71 CHAPTER IV. SOCIAL HOMES. Diversity of method of insect architecture, its beauty and size The word architecture as applied to this portion of insect economy Societies of social caterpillars Three types of nests of ants Home of common Wood Ant external conformation internal plan doors formation and regulation of society A solitary " queen" as founder of a colony Singularity of Wood Ant in preference for open-air life Mason Ants Extra- ordinary dimensions of homes of Saiiba or Coushie Ants Their leaf-cutting propensities Mushroom-growers Mason Ants of New World ; their disks, roads, refuse heaps, store-rooms, nurseries, lumber-closets, position as farmers, &c. F.fuliginosa and other carpenters Standing army of Bull's Horn Acacia Ants as guardians of other plants Remark- able pensile nests of Crematogaster, Myrmica Kirbii, CEcophylla sinaragdina, &c 118 CONTENTS xi CHAPTER V. SOCIAL HOMES (continued). I'AGE So-called humble-bees Eighteen or twenty species in this country Comparison of their habitations with the hive Description of nest of Carder The coping of moss Interior Dispersion of company and hybernation of females Work of latter in Spring Deep burrowers among British Wild Bees Honey- bees in East Stingless Meliponae and Trigonae of South America and their homes Supposed presence of several fertile females Sentinels to guard the gates True social wasps Their building-material and disposition of combs- Particulars of home of common English wasp British tree- wasps The papery envelope Nest of hornet Description of combs of Polistes and Icarias, without cover Apoica has a cover but not distinct Card-board makers Wasps as honey-gatherers 154 CHAPTER VI. DEFENCES OF INSECTS, OR PROTECTION AS DERIVED FROM COLOUR. Need of insects of means of defence Adaptation of their external colouring to conditions of life Protective Resemblances Herein find explanation of first and most wide-spread use of colour among animals Principle of adaptive colouring solved by theory of natural selection Commonness of general harmony between colouring of insects and tints of nature Imitative tints of undersides of wings of butter-flies Special Protective Resemblance "Stick caterpillars" and others- Leaf butterflies British and European Moths Among Or- thoptera Tropical "walking-leaf" and "walking-stick" insects Other insects and spiders Alluring Colouring Re- semblance of Mantises and Spiders to flowers To excreta of birds Changes of colour corresponding to changes of environ- ment Di- and Polymorphism Their value Meaning obscure Variable Protective Resemblance in pupae In larvae In colours of cocoons In perfect insects Variable Protective Resemblance and the origin of colour Power of adjustment of colour is adaptive, and is produced and maintained by natural selection 203 CONTENTS CHAPTER VII. DEFENCES OF INSECTS, OR PROTECTION AS DERIVED FROM COLOUR (continued}. FACE A conspicuously coloured group Objection to colour Different modes of msects of maintaining existence ; possession of nause- ous properties, irritating hairs and spines, the sting, hardness of substance, wonderful vitality, capacity for increase, attitudes Association of bright colour with distasteful qualities Bright colour as a warning ; its value Various combinations of means of defence Resemblance between Warning Colours and patterns ; determining causes of the repetition Distinction between Warning Colours and those produced by courtship Sexual colouring made use of for warning ; its similarity Con- spicuous and nauseous, but non-vital parts One meaning of broad expanse of wing of showy butterflies Mimicry Bates first to explain the facts Butterflies that are objects of mimicry in tropics Their unpalatability indicated by conspicu- ousness and abundance True Mimicry as distinct, from all warning appearances The term Mimicry Mimicry a phase of Protective Resemblance Mimicry of American butterflies, of the Asiatic, of the African, in British Lepidoptera Especially prominent in the female ; interpretation of pheno- menon Affords confirmation of theory that Mimicry is produced by 'natural selection" External conditions," "heredity" An explanation of sexual difference of form and colour Mimetic analogies among beetles Hymenoptera mimicked by Lepidoptera, Diptera, Coleoptera, Orthoptera, Hemiptera Mimicry of Coleoptera Of ants by spiders Of vertebrates Predaceous insects that resemble their prey, or a form to which their prey is indifferent The great frequency of Mimicry in insects 242 GLOSSARY OF SCIENTIFIC TERMS 275 INDEX 287 LIST OF ILLUSTRATIONS Nest of a Tree Ant Frontispiece. Larva of the Caddis-Fly (Trichoptera) 7"itle-page. 1. Pupa of a butterfly (Pieris brassiccz], protected by a hardened uniform case 9 2. Pupa of a Longicorn Beetle (Batocera titana], its limbs in separate sheaths 1 1 3. A honey-bearing ant (Myrmecocystus mexicamts) regurgitat- ing honey from her crop at the solicitation of hungry workers 47 4. View of honey-bearers, as seen in natural site, clinging to the roof of a honey-room .57 5. Profile view of nest of a Mining Bee (Andrena vicina, Smith), which builds her nest in grassy fields 72 6. Nest of an Australian Carpenter Bee (Lestis bombylans] . . 77 7. Clay nest of a solitary wasp (Eiimenes), in early stage, from Natal 80 8. Pelopseus Wasp building nest 85 9. Galls of Cynips insana, or Dead Sea Apples 90 10. A sack-bearing caterpillar 96 n. Metura Sander sii from Australia (a female) 97 12. Part of the nest of a trap-door Spider (Nemesia eleanora] with single tube 105 13. Part of the nest oil Nemesia meridionalis showing the surface- door open, and the lower door pushed across so as to close the principal tube. The subsidiary tube ends in a cul-de-sac 1 1 1 14. Nest of the Turret Spider (Lycosa arenicola] '114 xiv LIST OF ILLUSTRATIONS PAGE 15. Section through a typical nest of Formica 121 1 6. Section through the nest of the Leaf-cutting Ant CEcodoma cephalotes 125 17. Saiiba, or Leaf-cutting Ant, carrying leaf 127 1 8. Large flat circular disk and open roads of the Agricultural Ant of Texas {Pogonomyrmex barbatus] made above the subterranean formicary . 131 19. Agricultural Ants cutting down obtruding grass 132 20. Gravel cone nest of Honey Ant, built partly round a tuft of gramma grass 133 21. View of a nest of a Provident Ant (Attabarbara), from Men- tone, showing a granary excavated in rock, and the conical refuse heap .... 135 22. Fragment taken from the trunk of an oak inhabited by Fuli- ginous ants 139 23. Pseudomyrma bicolor inhabiting Acacia comigera 141 24. Nest of a Tree Ant (CEcophylla smaragdina) from India . . 145 25. Comb of a small Honey Bee (Apis floralis) from India ... 155 26. Melipona Bees gathering clay 158 27. Home of Vespa nonuegica 159 28. Comb of Polistes tepidus, Fabr., with central pedicle . . . 167 29. Comb of Polistes canadensis, Linn., inverted, with lateral support and irregular cells, many still containing nymphs . 167 30. Nest of Icaria variegata 171 31. Nest of a Brazilian Wasp (Apoica pallidd) 174 32. Wasps' nest {Chartergus apicalis\ from Brazil, interior and exterior 185 33. View of exterior of nest of Myrapetra scntellaris 194 34. View of interior of nest of Myrapetra scutellaris 195 35. A "stick-caterpillar" (Ennomos tiliaria), which in colour, form, and attitude, closely resembles a twig of a tree upon which it lives 207 36. Caterpillar of Early Thorn Moth (Selenia illunaria) showing supporting thread of silk 210 37. Appearance of the larva of Brimstone Moth (Rnmia cratagata) when seated among the twigs of its commonest food-plant . 210 LIST OF ILLUSTRATIONS xv PAGE 38. The hind part of the larva of Brimstone Moth (Rumia cratcegata), seen from the right, showing the claspers, and the fleshy projections which tend to fill up the furrow between the larva and the stem 211 39. Leaf Butterfly (Kallima) in flight and in repose 213 40. A " Walking Leaf" Insect 217 41. A "Walking-stick," or Moss Insect 219 42. Imitation of a flower by a Mantis (Hymenopus bicornis) in active pupa stage 220 43. A Bird's excreta mimicking spider 228 44. Pupa of South African Swallow-tailed Butterfly (Papilio nireus] attached to orange -tree, and corresponding in colour to its deep-green leaves 229 45. Pupa of Papilio niretis attached to woodwork, the colour of which it imitates 229 46. The larva of Peppered Moth (Amphidasis betularia) reared amid green twigs and leaves 236 47. The larva of Peppered Moth reared amid dark-brown twigs as well as leaves 237 48. Larva of the Buff- tip Moth (P. bncephala\ a caterpillar with Warning Colours and a nauseous taste 245 49. Hornet and Mimetic Bug 249 50. An Ant-like Spider 254 51. An Ant-like Spider 255 52. Adult caterpillar of the Large Elephant Hawk Moth (C. elpenor) when undisturbed 256 53. Dorsal view of the caterpillar of the Small Elephant Hawk Moth (C. porcellus] in its alarming attitude 257 54. The larva of Puss Moth (Centra vinula) resting; full-fed, natural size 261 55. The larva of Puss Moth in its terrifying attitude 263 ROMANCE OF THE INSECT WORLD NOTE. An asterisk indicates that the luord so marked is mentioned in the Glossary. CHAPTER I METAMORPHOSES OF INSECTS Character of life-history of insects Metamorphoses of the butterfly, beetles, &c. " Similarly-changing" insects The two series Heteromorpha and Homomorpha True meta- morphic stages considered in detail egg larva shelters for approaching change Meaning of pupa and other terms applied to stage Nature of condition in insects which undergo complete metamorphoses Signs of returning life Assumption of imago state Pseudo-imago Subsequent career Old idea of metamorphoses Modern theory Study of structures implicated External Modifications of internal organs Explanation of metamorphoses Apparent suddenness of changes Of the death-like period of quiescence. IN these days of universal education, no doubt it would prove a somewhat hard matter to discover any number of persons who were altogether unacquainted with the wondrous phases of insect existence. Many would be found aware, few not, that during the period B 2 ROMANCE OF THE INSECT WORLD CHAP. of their life-history, from birth to infancy and on to maturity, the great majority of the members of these little lowly winged tribes pass through a series of changes of condition, and assume several successive well-marked forms, to all appearances totally distinct the one from the other. In a general way the youngest persons, and the most ignorant, are in- formed of the fact, but how many, learned and ignorant and young alike, ignore it, owing to the commonness of the occurrences and the minuteness of the objects, and thus deprive themselves of the exceeding interest and pleasure to be gained from study of this, which is perhaps the most admirable of all the extraordinary pages of natural history. The butterfly, whose metamorphoses are so striking to the young, could have never existed as we now behold it, had it not successfully accomplished a regular series of changes of structure since the day of its birth. It is produced by the parent as an egg, from which it is hatched in the shape of a caterpillar or larva, a worm-like creature of soft and fleshy con- sistence, furnished with a mouth and a few short legs, its only requirement being an abundant supply of food. Of this it eats with an incomparable appetite, and makes haste to grow, necessitating repeated casts of skin. Eventually it becomes a shrouded chrysalis or pupa. This sleep being over, it awakens to a new life, having little resemblance to its old condition, in its aspect, or internal conformation, or in the work that has then to be done, a winged and perfect butterfly. In the case of beetles likewise, the larvse or grubs at their emancipation from the egg, though I METAMORPHOSES OF INSECTS 3 they differ much, are all more or less in an immature stage. Gradually the larvae alter to the quiescent pupae, the nymphs so-called, and from the pupa emerges the perfect beetle. Bees, wasps, flies, and many more undergo similarly marked metamor- phoses. The metamorphoses of some insects, however, are far less decided, as in the grasshoppers, locusts, crickets, earwigs, and a small group well-known to gardeners under the name of thrips. In these the larvae and pupae already greatly resemble the fully-developed parent. The changes consist prin- cipally in a gradual increase of size, with casts of skin, and as pupae the insects begin to show signs of the acquisition of wings. In certain cases the egg- stage is wanting, the larva being produced alive, There are rare anomalies in which development has been carried to a considerable degree before birth. The difference in the nature of metamorphoses has given rise to a simple division of insects into two series : Heteromorpha, according to Professor West- wood, or those in which there is no resemblance between the parent and the offspring ; and Homo- morpha, or those in which the larva resembles the imago, except in the absence of wings. In the former the insects may be said to undergo complete meta- morphoses ; as regards the latter, their metamorphoses are incomplete. It may be laid down as a universal law that all insects originate from eggs. The apparent exceptions com- prise the few instances where the young are hatched, or are retained within the body of the mother. The varieties B 2 4 ROMANCE OF THE INSECT WORLD CHAP. of eggs it is almost impossible to enumerate, among the butterfly families especially scarcely two forms are alike, even in the most closely allied species marked diversity occurs. They may be round, oval,* oblong, pear-shaped, lenticular,* or flattened like a lens. Many of them are petiolated,* or placed upon foot- stalks, which may be long and straight, or compara- tively short and bent. Others are provided with particular appendages to answer various ends. They are enriched with all the colours of the rainbow, though the prevalent hues are white, yellow, and green. Sometimes the outer coat is hard and firm, sometimes it is a mere filmy skin. The surface may be smooth and plain, or beautified with delicate sculptured designs, such as cross lines giving a reticulated * appearance, or these lines may be curved, as if the eggs were imbricated * or covered with tiles ; or the pattern may assume the form of decided knobs. The variation in external shape, markings, and colour is not greater than in the modes of dis- position of the eggs, and the localities where they are placed. They are laid singly or in clusters, and for the most part upon, or within, or near the substance, be it plant or animal, which will serve as the food of the larvae that will presently be hatched from them. As a rule, the peculiarities of form and colour bear relation to the circumstances of disposition, the objects to be ensured being safety from external injury and the proper development of the egg. Those eggs from which the larvae are most rapidly developed require the aid of the highest temperature and the fullest exposure to he atmosphere. i METAMORPHOSES OF INSECTS 5 Usually the formation of the larva is complete soon after the egg is laid, sometimes the process lingers on throughout the winter, and should unfavourable circumstances supervene, it is surmised that it may be delayed for years. Experiments prove that eggs may be exposed to intense cold, such indeed as to solidify their contents, and yet remain capable of hatching. The growth of the embryo * within the egg may be watched. This is easily perceptible in the case of a transparent egg, by holding it against the light, or by examining it through a strong magnifier. Day by day the germ steadily increases from a tiny speck, until it is too large for the egg to contain, and it breaks through the now tight skin or shell, and emerges into the world a living and active being the grub or larva. The word larva is from the Latin, and signifies a mask or phantom. It was applied by the great naturalist Linnaeus to the first active stage of insects, with the idea that during its continuance the glories of the future perfect creature were, as it were, masked or shadowed out. Unhappily there is no corresponding general term in English. The larvae of moths and butterflies, which are coloured and often hairy, are spoken of as cater- pillars. White fleshy and more compact larvae, legless, or possessed of legs, as those of many beetles and flies, are commonly known as grubs and maggots. Such as resemble the parent, as a rule are designated by the parent's name. It is interesting to follow the life-history of an insect that is subject to true metamorphoses. From 6 ROMANCE OF THE INSECT WORLD CHAP. the moment of its liberation from the egg as a larva* until it assumes the perfect form, its life is one continuous succession of changes. These are not merely from larva to pupa, and from pupa to perfect insect, for even while it is a larva it undergoes a series of sheddings of skin, or moults as they are called, previous to its attainment of its full size and growth. No sooner is a caterpillar hatched than it begins eating, its first meal often consisting of its discarded egg-shell. Perhaps this dainty morsel tempts the appetite, at any rate the hunger that the insect displays, and the amount of food that it requires to satisfy it are something wonderful. Naturally it increases immensely, and the skin has to stretch to allow of the greater bulk. By and by there comes a day when the skin will extend no more, it cracks, and the larva crawls forth, clad in a bright new coat. The process evidently produces the greatest discomfort and uneasiness. A few hours before the divestment begins the larva ceases to eat, and remains motionless, meanwhile the body suffers powerful twitchings and contractions. But when once the skin yields it splits down the back the actual withdrawal from the clothing is seldom of long duration. The external covering of the body is not the only thing that is cast. The whole internal lining of the mouth and the digestive canal, and that of the respiratory organs are likewise detached and come away with the skin. This change, though it is most conspicuous at the last moult of the larva, probably takes place at the occurrence of each shedding. I METAMORPHOSES OF INSECTS 7 After the operation, the creature is soft and languid, and pauses to recover from its exertions. Then it begins nibbling and devouring with increased voracity, since its digestive organs are now more capacious. Some insects make a fresh start with their old skin, but many at once remove to new feeding-grounds. Soon further enlargement necessi- tates a second change. The moults* vary in frequency in different species ; in general they occur about three times, or oftener. Usually the first takes place about the twelfth day, the second after the further lapse of a week, the third happens six or eight days later still, the power of consumption of food at each moult being augmented. Sphinx ligustri, the Privet Hawk Moth, is known to increase at the rate of over 11,000 times its original weight in the space of thirty-two days, a pro- portion, great as it is, largely exceeded by the goat moth, which increases to the amount of no less than 72,000 times its first weight, but this larva is very long-lived. Reason for the immense storage of food is found in the fact that all growth is effected in the larva and pupa stages, for when the insect becomes perfect it alters no more. The pupa* period is not only a state of death-like sleep, during which no food can be taken, it is the time when occurs the most rapid development of the tissues of the body. The nourishment accumulated by the larva has to admit of these alterations, and has like- wise perhaps to serve as an immediate source of nutriment to the insect on its awakening at the end of the important pupa season. ROMANCE OF THE INSECT WORLD CHAP. In some cases the duration of larval life extends over one, two, or even five years. In all species it is much influenced by the weather and other circum- stances, for cold as a rule retards growth and warmth hastens it. Many larvae have an almost unlimited power of endurance of cold, and may be frozen hard without the slightest injury. That a severe winter is highly beneficial for the crops in precluding proba- bility of insect attack in the following spring is utter fallacy. But though larvae will bear great cold, they are extremely susceptible to over-supply of moisture, whether from rain or from dampness of food, a characteristic worthy of consideration when attempt- ing to exterminate an insect pest. Suppose that an insect is near the completion of its term of growth, when for the last time as a larva it will cast its coat, and will emerge therefrom in the next stage of its existence a pupa. Great changes in its internal organs since its exclusion from the egg are beginning to take place, and greater ones are yet to come. As before its previous but less momentous larval skin-sheddings, it seems to suffer inconvenience, it becomes exceedingly restless and irritable, it neglects food and diminishes in weight, and, as if aware of its distressing delicacy and defencelessness when the skin is abandoned, as a rule it makes haste to seek or construct some shelter with care and con- sideration, where, secure from harm, the otherwise disastrous revolution may be effected, and the hapless stage of pupal life may be lived through. Many species, like the silk-worm caterpillar, secrete and draw a gummy fluid from their mouths, and spin a METAMORPHOSES OF INSECTS cosy silken nest or covering around them, known as the cocoon ;* occasionally the silk is mingled with particles of wood or earth. Some of the butterflies simply suspend themselves vertically by their hinder- most legs, head downwards, or they carry a silken cable across their body to keep them from falling, affixing the girdle to the under-surface of an object such as a leaf or twig. Many insects hollow out a cell or cavity in the ground and line it with web of silken material. The larva being duly prepared, after a short repose its skin splits, and with infinite shuffling and wriggling is thrown off, and then the insect is known as a pupa. In the true flies the outer skin of the full- grown larva is not shed, the maggot contracts, while the skin gradually hard- ens, assuming the appearance of an oval brownish shell or case, which serves the same purpose as a cocoon and affords an admirable protection to the insect which changes to pupa inside. -pi ,1 *i_ i i j brassic(e) protect- The being that emerges in its bright ed by a hardened i . rr c 11 uniform case, se- new coat is very different from the larva, creted from the - , . - 111 pores of the insect. tor the muscles have already shortened and enlarged in certain parts, so modifying the simple worm-like form that the entire shape and limbs of the future perfect creature are apparent, and the wings, though they are very small and in rudimentary condition, may be plainly traced. The new pupa, should it be that of a butterfly (see Fig. i), as of Sphinx, having got rid of its larval skin, io ROMANCE OF THE INSECT WORLD CHAP. hangs for a few seconds at rest. It suffers some powerful contractions and alterations, and the wings become much enlarged ; moreover, a very transparent fluid secreted from the pores which facilitated the slipping off of the ' discarded skin, is now diffused over the whole body, and as the insect sinks into quiescence, dries and hardens into a compact protective covering, uniting and supporting the tender and erstwhile separate limbs. To the pupa the terms nymph, chrysalis, and aurelia are also given. The two latter names were used by the older entomologists, the first by the Greeks, the second by the Romans, for this stage of transformation in the butterflies and moths, being expressive of the glittering golden colours or spots with which many pupae of butterflies are adorned. ' Nymph ' is applicable only to those pupae in which the limbs remain free in separate mem- branous skin-sheaths, folded beneath the breast and body (see Fig. 2), as in many of the beetle and bee tribes, unlike the common uniform covering of Lepi- doptera. At present the term is usually confined to active Homomorphic insects when in this stage. The word pupa itself, meaning an infant, was adopted by Linnaeus as a general term for the period. It is peculiarly appropriate, for insects in this state are approaching their completion, but are not fully deve- loped, either in their limbs or functions, and in many cases recall the condition of a child swathed or bound up as in barbaric fashion. The pupae of flies, where the insect is enclosed within the smooth uniform case formed of its own cast larval skin, but no limbs METAMORPHOSES OF INSECTS ii and other parts of the body are visible externally, is called 'coarctate.'* In insects which undergo complete metamorphoses the pupa is a most remarkable and characteristic condition. Almost as long as the state continues, the insect usually lies quiescent, capable of only the faintest motion when touch- ed, in a seeming deathlike torpor, tasting no food, and the vast change which was beginning when in many instances the larva took shelter is gradually com- pleted, incapacitating the creature for a continuance of its previous life, while adapting it for life in the future. It is no wonder that the period of such organic evolution is at the same time one of great functional inaction, which lasts longer than the rest succeeding - n FIG. 2. Pupa of a longicprn beetle each minor Skin-Shedding (Batocera titana\ its limbs in separate sheaths folded beneath the breast and that has gone before. Res- bod y- piration and circulation, for instance, are reduced to a minimum. Some insects remain in pupa for a very long time, particularly true of the Sphinx moths, which often continue in chrysalis for nine months of the year. But on the other hand, as regards ants and bees and many others, it is the shortest period of all, and occupies little more than a 12 ROMANCE OF THE INSECT WORLD CHAP. week or ten days. In every species the length is much affected by the weather. Should a butterfly larva turn to pupa during the summer, it may become perfect in eight or ten days, but if it reach the chrysalis state at the approach of winter the change to butterfly may be delayed for months, until development is quickened by the warmth of returning spring. Reaumur discovered that if a chrysalis were deposited in an ice-house, further transformation might be retarded for two or three years. If one deep in its winter sleep were brought in from the cold to great heat, the final metamorphosis might take place in ten or fourteen days. As the structures become completed, and the hour for entering the imago condition draws near, the immobile pupa begins to show signs of returning life. In Sphinx respiration increases rapidly, twitchings and contortions indicate what is about to occur, and the form of the coming insect becomes more and more apparent. In every instance the assumption of the perfect state is accompanied by a casting of the outer skin. Before this can be effected, many insects have first to acquire the power of locomotion. Caddis flies which undergo their previous metamor- phoses in water, must be able to come to the sur- face, or to quit an element in which they cannot now exist. Pupae that are lodged in the interior of trunks of trees, or in crop stems, or beneath the ground, usually issue forth from these situations ; and many Lepidoptera and others have to struggle through silken wrappings. Having overcome the obstacles that oppose its escape, the pupa bursts I METAMORPHOSES .OF INSECTS 13 its covering, and the insect emerges perfect in all its parts. Sometimes a little while elapses ere it takes to flight. The wings of butterflies and moths are somewhat drooping and difficult to spread, and the body is humid and soft. After considerable res- piratory effort, and a rest, and exposure to the drying influence of the atmosphere, the imago gains strength and solidity, its wings enlarge and expand, and at last it enters on its higher career and the delight of finished faculties. Humble bees do not at once come abroad to the outer air in their new dress. Their bodies are excessively moist and weak when they emerge from the cells, and their hairs are of a whitish gray. They crowd together in the nest, and seem to feel the chill of diminished warmth. In a few hours the susceptibility vanishes, and the proper colours are acquired, but the bees are not vigorous or capable of great exertion until the following day. When an insect has withdrawn from the pupal case it is perfect in form, its internal organs are perfect, and metamorphoses are now concluded. An apparent exception to the rule occurs in the case of the May- flies (Ephemerae).* The pupae creep out of the water, and perform the feat of getting rid of the pupal covering, their wings expand, and they take feebly to flight. Shortly however they settle again, and having shed an extremely delicate skin, re- new their aerial excursions with redoubled energy. The condition previous to the final moult has been called the pseudo-imago. Metamorphoses being over, the task for the re- H ROMANCE OF THE INSECT WORLD CHAP. mainder of life, which is often an ephemeral span, is to propagate the kind. Numerous adults perform this work unhindered by any other desire, even that of partaking of food. The female lays her eggs, and then (usually) dies, and so the cycle of existence is complete. Many an insect lives merely one short year. Generally speaking, it is in summer or autumn that the parent produces the eggs, which quickly hatch, and in the state of larvae, or more usually pupae, the young hybernate, or sleep in shelter during the winter, and become perfect in the following spring. The mother seldom long survives the laying of her. e gg s - However, these points are liable to much variation, according to the seasons and the different species. The term metamorphoses or transformations which is applied to these changes that insects undergo as life proceeds, before they arrive at their perfect state, is at first maybe a little misleading. From the earliest times civilised nations have produced students of nature who have marvelled at, and watched, and endeavoured to explain these strange alterations. The old ideas on the subject were wide of the truth. It was believed there took place a complete transformation of one being into another a trans- formation as startling as though a serpent turned to a bird and that the* most singular poetic by- gone fables of metamorphoses were repeated in the case of insects. Modern research, aided by the microscope, has proved this opinion to be incorrect. These transformations are so many stages or seem- ing pauses in the natural course of a progressive I METAMORPHOSES OF INSECTS 15 development or evolution of the one self-same animal. The caterpillar in the egg is already possessed of the principal vital organs, which have to be modified and perfected ; others appear later on ; and often early- existing structures die away as growth advances. Nothing will more plainly show the fact that meta- morphoses are but a progressive development of the immature into the mature being than a brief examina- tion of some of the structures which are altered, and of those which put in their appearance during the successive stages of life. An insect may be broadly defined as an animal that is formed of a series of rings or segments.* They can be traced in the embryo within the egg, they are seen plainly in the larva, and can be distinguished in the perfect insect. The normal number of distinct rings in all insects is probably thirteen. The first consti- tutes the head. In most larvae the remaining twelve are equally developed and differ little from each other in general appearance. But an imago is evidently distinctly divisible into three pieces the head, the body or thorax, and the abdomen. How- ever greatly the forms of these regions may vary, the difference is simply due in each case to greater or less development of the primary segments, and in many cases the various segments can be satisfac- torily numbered and recognised. A difficulty lies in the fact that the changes are not brought about by alteration in the consistence of the integu- ments only, but by the union of several segments into one or more separate consolidated portions, and by the greater or less retraction of segments, each 16 ROMANCE OF THE INSECT WORLD CHAP. within tlje one which immediately precedes it. Thus their number becomes diminished, yet a segment never entirely disappears, but invariably leaves trace, however faint, of its former distinction. So far as can be ascertained, the second, third, and fourth rings of the larva go to form the thorax of the perfect insect, the remaining nine constitute its abdomen. The fifth however enters in part into the composition of the thorax and forms the connection of that portion with the abdominal region. It is frequently atrophied,* and has almost entirely disap- peared. If this piece be excluded, the abdomen is composed of eight segments. Any deviation from the rule in regard to reduced numbers will be found to be apparent and not real. The larvae of some insects are entirely destitute of legs and feet, as in the bee family and among flies, and the body is otherwise modified where power of locomotion is required. Many larvae, however, possess pedal* appendages of two classes. These are true legs, six in number, arranged in pairs, always on the three segments of the thorax. So-called false or abdominal legs are attached to the segments of the .abdomen, their number ranging from a single couple even to eight pairs. The true or thoracic legs of young insects are very small and scale-like, and are distinguished from the false legs by distinct articulations or joints, by their strength and firmness of texture, and their general pointed form. The whole of these thoracic legs in all larvae that possess them are nearly equally developed. In structure and appearance the false legs are totally different. I METAMORPHOSES OF INSECTS 17 They are soft and membranous,* and their forma- tion is often exceedingly curious ; in every instance they are only processes* of the exterior covering of the insect. But the difference between the two kinds which must be particularly pointed out is this. The true legs are those which enlarge and otherwise develop into the limbs of the future imago, whatever be their size or variety of form, whereas the ab- dominal legs are not persistent,* but are lost with the cast skin during the metamorphosis of the larva into chrysalis. Here then is a clue admitting of the recognition with certainty of the individual segments that compose the thorax, however much the distinc- tion between them may have become obliterated in course of development. Each pair of legs in the perfect insect answers to each pair of true legs in the larva. In the case of larvae that are destitute of true legs, these wonderful organs have to be developed with all their muscles and nerves during metamorphoses. The thorax,* which thus gives origin to the legs, is usually large, and the union of the segments is firm in proportion to the rest of the body. On the size of these segments and their consolidation greatly de- pends the strength of the insect. This region also supports the wings ; to be precise, these appendages are attached to the two hinder segments, the meso*- and meta*-thorax. The development of the thorax is not surprising, for there must be abun- dant space within for the muscles which move the organs for walking and for flight. There is little trace of wings in the caterpillar, so that the formation C i8 ROMANCE OF THE INSECT WORLD CHAP. of these organs as is mainly the case with the legs may be said to occur during the pupal period of rest. It follows that the great enlargement of the thorax as seen in the perfect insect does not generally take place until the chrysalis life has progressed. The wonderful and delicate organ called a wing is, to all appearances, composed of a simple mem- brane.* In reality it is double ; and between the two tissues a multitude of minute air-vessels ramify through every part, accompanied by canals or passages for the circulatory fluids. Imme- diately after the assumption of the perfect state these tracheae become solidified like the rest of the skeleton. They are hollow for the reception of air, and afford strength and lightness to the wings, the motions of which are intimately connected with the function of respiration. The membranes are con- tinuous with and expanded portions of the common tegument * of the sides of the segments of the thorax. Their surfaces may be transparent, or coated with dusty scales of microscopic size. The distribution of the contained tracheae, or neuration,* and the appendages, though of the highest intrinsic interest, are outside the present subject. The abdomen,* the third division of the body of an insect, is the seat of the greater part of the digestive organs, the respiratory and circulatory, and the generative systems. The head of some larvae,tlike "the" rest^of the divi- sions of the body, is covered with] soft; flexible skin. Usually it is rounded or oval in form and of harder texture than the other segments. Three great pairs I METAMORPHOSES OF INSECTS 19 of attached organs, the mouth organs, are situated at its inferior surface, and at the lateral and anterior surfaces it carries the rudiments of antennae,* or feelers, and the eyes where they are present. In the perfect insect, the number and position of these parts are precisely similar. It is only in a manner true to say that the head of an insect is composed of one segment. For though at the birth of the larva no satisfactory separation of this portion into segments can be detected, it is a fact that it, like the other regions, is made up of several rings. The exact number which enter into its com- position has not yet been made absolutely clear. Probably the head appendages which form part of the organs of manducation are the proper articulated members of distinct rings, and are analogous to those which constitute the locomo- tive organs of the body. Since each pair of the latter is attached to a particular segment, in the same manner it may be presumed that the mouth-parts were attached, indicating an early separation of the head* into three segments. Probably there were four, and perhaps five. In many larvae a projecting papilla, the spinneret, is situated within the mouth. It opens into the glands that secrete the silken material with which the owner spins its cocoon, and performs similar tasks. It is an organ its function being no longer needed that dies ere the insect reaches its perfect stage. While still in the glands, silk is a thickish viscous * fluid. When about to make use of it the larva places the spinneret in contact with some object, and quickly withdraws it, at the same time C 2 20 ROMANCE OF THE INSECT WORLD CHAP. exuding a drop. The silk immediately hardens on exposure to the air, and is drawn out into threads equally remarkable for fineness as for strength. In the perfect state of insects the skin may be tough and thick, but still flexible ; while in the case of the beetle it is so dense and hard as to appear like horn. But though the variation is great, this tissue is invariably composed of a peculiar substance called chitine. It is formed of two layers, an inner one which is soft, and not made up of chitine the true skin ; the other is external and superficial the epidermis,* which is capable of becoming hard and horny. Both are intimately connected. It is the epidermis that is cast at the transformations. From its inner layers the new skin is developed, and peels away as it were from the outer ones, when the latter soon dry and become shrivelled and are thrown off, and the new skin eventually clothes it- self with a fresh epidermis. Newport infers that chitine,* the basis of the insect skeleton, is inter- mediate in its chemical condition between the bony and dermal structures. In other words, it is bony matter imperfectly developed, so modified that while it affords the animal strength and solidity, it at the same time admits of the performance of all the organic functions of the true skin. And it may be that its exuviation* is due not only to the continuous growth of the insect, which causes the body to become too large for the covering to contain but to changes in the actual condition of the skeleton* itself, dependent upon the same laws of existence I METAMORPHOSES OF INSECTS 21 which regulate the removal of the old and the deposi- tion of new matter in the bones and other structures of vertebrates. 1 The modifications of the outsides are not more remarkable than the changes that take place in the internal organs during progressive development. Many persons do not think that a larva has any internal organs at all. They hold the opinion of the gentleman who once confessed his belief to the well-known naturalist, the late Mr. Wood, that a caterpillar is " nothing but skin and squash." In fact, larvae live only for eating, so that their inward arrangements consist almost entirely of the digestive system, which in many is scarcely more than an elongated tube or sac very much dilated, serving as a most capacious stomach. As such it exists in the apodous * larvae of some of the bee family. In other members of the order it is more complicated, and it would be pos- sible to go through a list of larvae whose digestive organs gradually rise in the scale of importance, until they become fairly developed and the simple tube begins to assume the intricacies that it possesses in perfect insects. Turning to the latter, the form of the system is not more indicatory of the habits of the species than in larvae. Regarding it in a general way, the alimentary canal becomes a long convoluted organ, and shows certain swellings and constrictions, which mark its division into several compartments. Each exhibits distinct difference of texture and is adapted to peculiar function, 1 Newport. 22 ROMANCE OF THE INSECT WORLD CHAf. though all are subservient to the one end, the assimi- lation of food into matter fitted for nutrition.* New structures are likewise added of which formerly there was no appearance. Taking the principal parts of the tube in their order of succession from the mouth, with which the digestive structures are continuous, an oesophagus, or gullet, a stomach, and a small and large intestine may be distinguished. Glandular appendages complete the apparatus. Food passes from the mouth into the gullet, or oesophagus,* a portion of the tube that runs through the thorax in a straight line. In the case of insects that live on fluids it is usually narrow, when the diet is more or less solid it becomes comparatively wide and strong. A dilation of the gullet, called the crop, is often present, where food may be stored for a time previous to digestion. This is a provision common in gross feeders, such as grasshoppers and locusts, and in those that provide for the wants of their young. From the crop the bee disgorges its gathered honey into the cells of the comb by means of the muscular coats of the reservoir. A valve * cuts off the membranous bag from the true stomach, and must effectually prevent all regurgitation * from the latter into the former. In butterflies, and occasionally in flies, the crop is rather more separated from the gullet, and opens into it by a tube or neck. The stomach, the principal organ of digestion, varies much in length and in size generally. Here the food is mixed with the gastric juice, and is finally converted into chyme, just as in ourselves and the higher animals. As in man, the secretion depends upon the I METAMORPHOSES OF INSECTS 23 state of the stomach, whether it is filled or not. When the stomach is empty the juice is not secreted, upon the introduction of food the glands secrete actively, and the juice becomes acid. Obviously the secretion must be almost continuous during the life- time of a larva, which seldom ceases to eat. But as the perfect stage is approached, the glands are atrophied and dwindle away, and sometimes become altogether obscure. Their development is best in animal feeders ; in herbivorous insects they are much less conspicuous. The modifications of the intestines are of less consequence than those of the other parts. Salivary glands are situated one on each side of the oesophagus, and provide saliva* to mingle with and lubricate food in the mouth, and to assist in its digestion. They are largely developed in Lepidopterous larvae, in which they form the web- spinning apparatus and secrete silk. When the cater- pillar has completed its cocoon, and turns to chrys- alis, there is no further need of silk. Consequently the glands become small, and their function is altered. At first sight nothing could be more astonishing than the difference in the nervous system, as regards the size and relative position of its parts, at the various stages of development. A minute examination before and after metamorphoses reveals that it undergoes no perfect alteration of plan. The nervous system of the larva is merely adapted for the imago, and the original design is constant, even in the structures of the most highly elaborated insects. In its simple form, in a vermiform * larva, the system exists in the 24 ROMANCE OF THE INSECT WORLD CHAP. form of two longitudinal cords, extended from the tail end of the body along the median line of the under-surface, parallel with each other and close together, excepting at their anterior part, where they separate and pass upwards to encircle the gullet be- tween them, re-uniting above it in the head. Each of the cords possesses a series of enlargements, or ganglia, throughout its course, situated at certain distances apart, their number corresponding to the number of the larval segments. They are precisely similar in position in both cords. Though appar- ently a simple structure, each cord is in reality composed of two distinct but closely united columns of fibres, placed one upon the other. The under or external column, which is nearest to the exterior of the body, alone bears the ganglia, the upper one, next to the digestive organs, is entirely wanting in knots. These cords together are believed to repre- sent the cerebro-spinal system of vertebrates. The ganglion-less internal column of either cord is prob- ably analogous to the motor nerves of the higher animals, and the external column which is possessed of ganglions,* answers to the sensitive nerves of the vertebrata. Thus the two cords are each composed of a motor and a sensitive column. The double ganglia in the head, situated over the gullet, are the largest, and represent the brain. These and the ganglia previously described regulate the animal life of the insect. The vegetative life beyond will-control is maintained by an off-shoot from the principal nervous structures. Just as the body segments of the larva coalesce in I METAMORPHOSES OF INSECTS 25 the perfect insect, so also portions of the nervous structures, the disposition of which is in remarkable relation to the segments, become concentrated to perform the perfected functions of this wondrous system. Instead of the nervous matter being almost equally distributed to every segment, the ganglia of the different segments approach and become aggregated, the cords are shortened and enlarge into fresh trunks, and nerves alter in position and unite into one bundle, changes that are brought about and rendered necessary by the other changes that take place in the body. This concentration is most marked in insects that undergo complete metamor- phoses. The greater proportion of the nervous masses is removed to the head and thorax, appar- ently as a means of concentrating the energies of these particular regions. In some insects especially, the ganglia are usually aggregated together in certain segments, in the part of the body that is very actively employed. A most curious union and complexity occurs in the distribution of nerves to the wings. These, the most powerful and constantly employed organs, must act not only with energy, but in per- fect unison with each other, and hence must be supplied with power from the same centre. The union exists in many insects of rapid or long- continued flight, while in heavy fliers, or those accustomed to exert themselves for but short dis- tances, such combination is absent. The ganglia which form the brain are small in the larva in relation to the size of the head. They increase in the pupa, and attain their full development near the 26 ROMANCE OF THE INSECT WORLD CHAP. termination of that state. Then the cerebral mass acquires a compact form, it is more uniformly opaque than the other ganglia, and fills up most of the cavity that incloses it. If the metamorphoses of the nervous structures are wonderful, calling fresh senses and faculties into play, how shall be characterised the changes that take place in the organs of respiration ? There can be no comparison between the feeble respiratory * efforts of a sluggish caterpillar or grub, and the amount of breathing energy of a vigorous and nimble insect. The mode whereby an insect breathes is very dif- ferent from ours. It does not draw in air through one mouth, neither has it lungs, nor is the fluid answering to blood, which the air has to purify, contained in veins, it bathes the internal system. When the interior of an insect is carefully investi- gated, a multitude of the tiniest and most delicate tubes are seen branching to right and left, on one side towards the skin ; on the other they are distributed to the middle of the body, they cover the digestive organs, and enter amongst the tissues.* These are air-tubes, known as tracheae, their duty being to convey the air through every part of the insect. A trachea is a tube formed of two layers of membrane, inclosing between them a spiral convoluted thread. It is kept open by means of the spiral, which is very compressible, so that the amount of air any trachea may contain varies according to circumstances. The outside air gains admission to the tubes through small apertures, or mouths, called spiracles, which are situated generally at regular distances, their i METAMORPHOSES OF INSECTS 27 number being usually nine on each side of the insect a pair for the first segment of the thorax, and one for each of the eight anterior segments of the abdomen. Sometimes, as in the case of fly-maggots, there is only a pair of spiracles, which are placed at the end of the body or near it. These larvae embed them- selves in their nutriment, and would be stifled were they unable to draw in air through the exposed tip of the tail. Spiracles are of many forms of structure. Suffice it to say, they admirably guard the entrances to the tracheae, and are capable of closing them, preventing the intrusion of foul air and other im- purities ; this also permits of the retention of large quantities of air in the tubes. The spiracles of the abdomen are always much smaller than those of the thorax, and the posterior * ones, which were very im- portant in the larva, are almost imperforate in the later time of growth. The circumstance arises, prob- ably, from the change that takes place as regards the region of the body in which respiration is prin- cipally carried on in the two stages of insects. In the larva it takes place chiefly in the abdomen, in the imago in the thorax. In larvae the tracheae are always more diminutive than in perfect insects compared with the size of the individual, and are smallest in the footless larvae of the bee family, which live long in closed cells. Some larvae and pupae that inhabit the water breathe like fishes by means of branchiae, or gills, respiring the air which is mechanically mixed with the water. These branchiae are simply expansions of the external surface of the body, and, as a rule, 28 ROMANCE OF THE INSECT WORLD CHAP. are extended outwards from the sides. The insect possesses the voluntary power of moving them at pleasure, and thus effects constant renewal of the water in contact with the organ. They are abun- dantly supplied with minute ramifications * of the tracheal vessels, which are believed to convey the air that the branchiae absorb into the main tubes, to be distributed over the whole interior of the body, as in insects that live in the open atmosphere. Branchiae are of various kinds, but the most common one consists of slender hair-like structures, growing together in tufts, as in the young of the gnat. All perfect insects, whether they are inhabitants of the air or water, breathe air alone. By the time that this stage is reached, the branchiae, or other curious adaptations for the larvae, where they were present, are no longer distinguishable, and spiracles are always developed at a part of the body at which the branchiae were attached. After metamorphoses, the water-beetle (Dytiscus), for example, which leads an amphibious life, has the ordinary spiracles for res- piratory purposes ; but they are situated on the back, enabling the insect to breathe readily by coming to the surface. In the larvae of aH insects, the internal respiratory organs, or tracheae, are simply elongated and ramified tubes. But in adults these tubes suffer certain modi- fications, becoming dilated into an immense number of minute vesicles, or sacs,* a development well adapted to meet the exigencies of increased force and activity of habit. It not only allows of most extensive respi- ration, it enables the insect to alter its specific I METAMORPHOSES OF INSECTS 29 gravity by enlarging its bulk, rendering it better able to support itself on the wing with little muscular effort. That this is the use of the sacs may be inferred from their entire absence in larvae, and in insects that are not addicted to forsake the ground ; while they are largest and most numerous in volants having the longest and most powerful flight. It would be impossible to exaggerate the advantage of this beautiful provision to the humble-bee, which is compelled to be constantly on the wing. Its large and cumbrous body is fitted for all purposes of strength, but would undoubtedly occasion it inconve- nience and fatigue, were the apparently unwieldy structures not lightened in this remarkable manner. The development of the vesicles begins at about the period when the larva ceases to feed, preparatory to change to pupa. When an insect is quiet, or is walking, it breathes slowly, and there is little air in the tracheae. The body is heavy, and must contain more air before the creature can fly. Its act of respiration at this moment resembles that of birds under the same circumstances. It elevates its elytra, the anterior* pairs of spiracles are opened, and the air rushing into them, is extended over all the vesicles. The air-bags expand, which in- creases the bulk of the body, rendering it light in relation to the bulk of air it replaces, so that when the spiracles are closed at the instant the insect makes the first stroke with its wings, it is able to rise, and endure sustained and forcible flight with- out excess of exertion. Explanation is here obtained of the long and elevated voyages undertaken by hordes of locusts, which are not conspicuous for 30 ROMANCE OF THE INSECT WORLD CHAP. their lightness or over-activity. The muscular efforts of prolonged flight also heighten the animal tem- perature, and this tends to rarefy the air contained in the vesicles and tracheae. The question still naturally presents itself: Why do insects undergo metamorphoses ? Why should they, in attaining to maturity, pass through such remarkable development ? and Why should the course of development be apparently separated into three or four distinct states, by marked alteration in form ? In the first place it must be observed that most of the animal creation, of the higher classes at any rate, have equally to submit to metamorphoses, or in other words to difference in shape and appear- ance, and also in structure of internal organs, in their early life and in maturity. Thus many animals which when mature differ widely, show points of resemblance to one another in their young state. Besides, the embryo of every organism is believed to portray, more or less completely, the form and structure of its less modified progenitors, so that the changes of a single individual as it were exhibit in miniature, and in short space of time, organic evo- lution in general, which ages of indefinite duration have been requisite to bring about. In fact the great majority of animals do undergo well-marked metamorphoses, but often those most pronounced are passed through within the egg, previous to birth, and thus are not revealed, except to the eyes of the curious. 1 Birth, it must be remembered, is not the beginning 1 Sir John Lubbock. Herbert Spencer. METAMORPHOSES OF INSECTS 31 of life, but merely a particular stage in the process of development. The condition of the young may be well advanced before this event, or the reverse, birth may occur at an early period of development, and causes for the difference are readily discovered. Thus the apparent total discrepancy between the meta- morphoses of insects such as the locust or grasshopper, and the bee or fly. The two insects first mentioned have become highly developed before birth, the bee and fly have emerged into the world from the egg ere metamorphoses have far progressed. The terms larva stage and pupa stage are therefore somewhat arbitrary, since larvae at their birth from the egg are in many stages of youthful development. The metamorphoses of insects depend then first on the fact that the young quit the egg at a more or less immature stage of development. The external forces act upon them in their preparatory state, and are different from those which affect the mature form. Consequently it need cause us no surprise to find that larvae and pupae undergo changes which have refer- ence to their immediate wants, rather than to the condition which they will ultimately assume. As to the second part of our subject : the ap- parent separation of the development of insects into distinct stages. There is this remarkable point to be observed, that whereas the alterations in many animals go on so ceaselessly and so slowly that we fail to perceive them, in insects the changes appear to be excessively sudden. This does not apply to Orthoptera and others which undergo incomplete metamorphoses, whose development from birth to mature life is gradual 32 ROMANCE OF THE INSECT WORLD CHAP. and not violent and great. But leaving these cases out of the question, the fact remains that an insect's life is generally apparently devisable into four well- marked states, and the change from the one to the other appears to be quite abrupt. In reality the metamorphoses of insects, like those of all other animals, arc continuous. The whole alteration, from the egg to the caterpillar, to the pupa, and from this to the perfect insect, proceeds gradually, and the striking changes in outward form, which take place from time to time and very rapidly, are simply due to a throwing off of the outer skin revealing a creature which, far from being new, has been in preparation for days ; sometimes for months. 1 The skin of an insect is very different from our own and from that of other vertebrate animals. It serves in place of a bony skeleton, and is more or less hard because to it the muscles are attached. When it is once made it cannot be altered, and consequently no change of form is possible without a cast of skin. In the case of many larvae the moultings are necessitated principally by growth and increase in size ; the alterations of structure are confined to the two last and more important skin-sheddings. Thus, then, the apparent abruptness of the changes of insects is to be attributed, in great measure, to the peculiar nature of their skin. That material change of form is often delayed until towards the latter end of development, or until the period of pupa, may be accounted for partly by the structure of the mouth. That of the 1 Sir John Lubbock. I METAMORPHOSES OF INSECTS 33 caterpillar is provided with jaws, fitted for eating leaves, whereas the mouth of the butterfly is suctorial, and capable only of sucking the nectar from flowers. It is clear that were the mouth of the larva meta- morphosed into that of the perfect insect by a series of small changes, the insect in the meanwhile would be unable to feed, and must die of starvation in the midst of plenty. In insects like the locust, whose changes are gradual, the mouth of the so-called larva resembles that of the perfect form. No doubt to this change in the mouth-parts, and to the similarly rapid and extensive alterations going on in the pupa, is to be attributed the strange, and otherwise incomprehensible, immobility of this re- markable period. Not only, as in that of a butter- fly, the mouth is in a state of transition, the digestive organs and the important muscles, and even the nervous system, are in course of rapid change. It must not be forgotten that all insects are inactive for a longer or shorter time after each moult. The period of inaction varies, being short as a rule when the change is slight, and becomes correspondingly pro- longed as the change increases in magnitude. The quiescence of the pupa is therefore not a condition peculiar to this stage, but an exaggeration of the rest that has succeeded every previous change of skin. 1 1 Sir John Lubbock. D CHAPTER II FOOD OF INSECTS Chief sources of food Almost limitless choice from vegetable world Death's Head Moth as a thief Animal-feeders Parasitic Hymenoptera and others Mighty business of insect-parasites upon insects Larva of the Tabby An- other strange food of animal derivation Ants and their aphides Intimate connection of ants with other insects Usual restriction of insects to vegetable or animal diet- Change of diet at different stages of life Need of nurses by the young of the Social Hymenoptera Livelihood with- out industry Slave-makers Honey-ant Analogy be- tween its economy and that of bee in storage of food Harvesting ants in the East, in Europe, in America Time of feeding Instruments of nutrition High adaptation of Lepidoptera to floral diet Means of procuring food Stratagem of ant-lion. LIKE the rest of living creatures, insects derive their nourishment chiefly from the animal and vegetable kingdoms, but they enjoy peculiar advantage over others, in that while the larger animals are more or less restricted in choice, as regards the vegetable kingdom especially, the bill of fare presented by nature to our little subjects is practically almost without limit. From the mighty banyan tree of India, covering acres CHAP. II FOOD OF INSECTS 35 with its stems and foliage, down to the tiny fungus scarcely visible to the naked eye, perhaps not a single plant exists which does not furnish forth delicious eating to some one of the vast tribes of insects. How different it is with the more imposing beings ! To them a considerable amount of vegetation is abso- lutely poisonous the acrid euphorbias, the henbane, hemlock, and deadly nightshade, and a still greater proportion, if it is not actually injurious, is so dis- tasteful as to be seldom or never utilised. The common nettle is by no means highly esteemed by ourselves or by the higher animals in general, yet it is all-important to insects, since it sustains the life, so at least it has been computed, of no fewer than thirty distinct species ; and the cabbage, while it is serviceable enough in its way to man, is of inestimable value to insects, which to the number of two hundred kinds feed upon its substance, or upon insect vegetarians that indulge in this diet. The larger herbivorous animals have to remain con- tent with certain parts of plants. They can subsist upon the leaves, the seeds, the fruits, occasionally on the tender stems and roots ; the flowers are attacked rarely, the woody trunks of trees never; but to insects no portion could be named that ever comes amiss. Not that insects are indiscriminate feeders, generally speaking ; far from it. Many are restricted to one particular sort of plant, and having fed for a time on it, will die rather than partake of change, and their size is such that they can select a special portion with the utmost nicety. Among those that appreciate the roots and stems, some confine themselves solely to the D 2 36 ROMANCE OF THE INSECT WORLD CHAP. outer bark ; the elm-tree beetle (Scolytus) burrows mainly in the inner and softer layers, the goat-moth caterpillar penetrates to the living wood, and others, as the beetle that infests the pine, bore into the central pith of young shoots, doing incalculable injury to pine plantations. To turn to those whose preference is for leaves and leaf-blades, the plant-lice, or aphides as they are called, imbibe alone the juice or sap ; a large number of the young of tiny beetles, flies, and moths taste solely the cellular substance, or par- enchyma,* disdaining the tough skin or cuticle as being much too gross for their delicate appetites ; at times only the lower surface of leaves is eaten ; while caterpillars as a rule are far from dainty, and de- molish leaves whole and entire. With respect to insects addicted to flowers, the earwigs and thrips, for example, choose the beautiful coloured petals ; some select the pollen; and an innumerable host moths and butterflies, bees, ants, flies, and many more make any effort to obtain the honey, that especial delicacy secreted in the nectaries. The Death's Head Moth is excessively fond of it, and enters the hives of bees, knowing in some astonishing way that honey is to be had there. Oddly enough, the bees do not rush upon the intruder and thief, but use every artifice in their power to exclude it, or to wall it up. Nor are insects restricted to vegetables in their fresh or unmanufactured state. They will secure their livelihood from a piece of furniture, or from the wood- work of buildings hundreds of years of age ; they even feast upon what one would imagine had surely been robbed of all sweetness and succulence the n FOOD OF INSECTS 37 dried flowers of a botanist's collection. Nevertheless their bodies are often as well stocked with fluids as are leaf-fed caterpillars. Insects that feed on animals can boast of a diversity of food nearly equally great. While the Sexton, or burying beetles favour dead carcases, the majority are adapted for living prey. A class of these, the parasites,* form one of the most curious and interesting phases of all methods of insect life. There are the Strepsiptera, parasitic throughout their lifetime upon bees and wasps. There are the gad-flies, which, as adults, pierce the skin of cattle and horses, maybe of ourselves, and suck the blood. There are the young of various bot- flies that insinuate themselves beneath the hide of the ox, or deer, or goat, and procure regalement in the swelling caused by the irritation produced. They likewise penetrate into the nostrils and head of sheep, and the stomach of the horse or cattle, being carried thither by the tongue of the animal in licking- its coat, whereon the insect mother had previously laid her eggs. The mites, and ticks, and fleas infesting animals and birds need not be more than mentioned. Numerous flesh-feeders kill their prey outright. They devour either its solid parts, or merely drink in its juices, rejecting the dry frame. The subject of insect parasitism upon insects is a very fascinating one, but for want of space it is im- possible to linger long upon it here. Unfortunately, anything like an adequate conception of the absorbing interest of the study cannot be gained by a brief notice. The leading parasitic families of the order 38 ROMANCE OF THE INSECT WORLD CHAP. inclusive of the bees (Hymenoptera) constitute a little world by themselves, but though their numbers are enormous, all alike are guided by the same general habits and instincts. Few insects, if any, are exempt from their attacks. Usually the female seeks out a caterpillar, a larva, or insect suited to her purpose, and lays her eggs in or on its body, and the larvae that are born of these eggs feed upon the fatty tissues of their host, leaving its vital organs for a time unin- jured, for were the host to die the parasites could not survive. The internal parts of the victim are not de- voured until the parasitic larvae are nearly full-grown and fed, and ready to change into pupae, when a pro- longation of the life of the unfortunate creature is un- necessary. In some cases the victim, should it be a caterpillar, continues to feed and live as though nothing were amiss subsequent to its reception of its unwel- come guests. It may even manage to turn to chrysalis; but it never attains to the perfect form, when it could lay eggs and reproduce its kind, because invariably ere it reaches the final stage the maturing larvae it con- tains have destroyed it, by a slow but sure consump- tion. Thus it often happens to a butterfly collector who has been looking forward to see a fine butterfly emerge from its chrysalis, to be disappointed, and to feel chagrin, by the appearance of several little parasitic Hymenoptera,* which, unknown to him, the butterfly has all along been sustaining, and to whom it has at last been compelled to yield up its life. When a parasite in open day finds an insect that will answer admirably as the nourishment for her future larvae, and deposits an egg in it, the act does II FOOD OF INSECTS 39 not involve any marked degree of cleverness, nor is it difficult to comprehend. But by what power does she become aware of the presence of a suitable host inside fruit or the branch of a tree, and completely concealed from sight ? She discovers the exact spot where it lies hid, and, with her long ovipositor,* pierces through the bark, or solid wood, or skin, as the occa- sion requires, driving her eggs into closest contact with the selected victim. When one ability fails to be use- ful under the circumstances of life, another is believed to come into prominence to supply its place. Her eyes * cannot assist her to this knowledge, which has been attributed to the sense of smell, aided perhaps by that of hearing, but these matters await elucidation. The mother's capacity, as it were, to gauge the appe- tites of her young is equally extraordinary creatures of which she can know nothing. She is no miserly caterer, but is ever careful to provide them with nourish- ment in quantity enough and to spare. A large parasite lays only a single egg at a time, because its larva is capable of consuming the recipient's entire substance ; had it been accompanied by brother-larvae, they must all have come to grief by starvation. If a somewhat smaller parasite avails itself of a great host, then two or three eggs are introduced ; and should the ichneumon * be very diminutive, the host may receive as many as fifty or sixty, or more. But these insects seem in- capable of altering their proceedings according to the occurrence of events. Each follows the same plan for generation after generation, without variation. If a large parasite came across a bigger host than it had ever met before, it would bestow only a single egg 40 ROMANCE OF THE INSECT WORLD CHAP. upon it, and a small parasite would always lay pro- lifically, whatever might be the size of the receiver detected. Sometimes parasitic larvae are so excessively minute as to find accommodation and nourishment in the eggs of insects. Those of many Lepidoptera, of a small beetle and of the dragon-fly are thus de- stroyed. Pupae are also invaded, as well as imagos. Of all the conditions, however, that of the grub or larva is princially liable to these terrible attentions, because it is often the one of longest duration, and therefore best calculated to carry out the object of the parasite ; whereas the adult, and chrysalis, and egg- stages are in many instances brief, and more likely, the first and last especially, to be cut short by acci- dent. Strange to say, insects which have long adult life are subject to parasites, whilst those to whom an ephemeral career is meted out go free. Weevils are long-lived, and though encased in what would seem impenetrable armour, and able to withstand the assaults of many a large and open foe, they are per- vious to the lancet-like sting of the indefatigable and more insidious assailants. These parasites have a mighty business in the world, being the means employed by nature to keep within due bounds the superabundant multiplication of the phy- tophagous, or vegetable-feeding, insects, which would often increase to an unwarrantable extent, and do in- finite mischief were it not for these appointed checks. They perform a marvellous work to our advantage, which is the more evident when we consider them in relation to insects injurious to the crops. They afford ii FOOD OF INSECTS 41 a wonderfully great protection from those most trouble- some pests, one in a sense superior to all the arti- ficial methods of prevention that were ever devised, inasmuch as they cost us absolutely no trouble and no expense. The balance of life between vegetables, in- sect pests, and their parasites is indeed extraordinary, and we cannot be too careful of instituting measures tending to upset, even ever so little, nature's ap- pointed ways. Not only animals themselves, animal matters in great variety constitute the food of many insects. Hair, wool, leather, silk, fur, even feathers, are not de- spised, and the grub of a beetle, with powers of diges- tion that a dyspeptic might envy, can subsist on horn. The larva of a moth popularly styled the Tabby (Aglossa pingiiinalis}, known both in houses and stables, has the still more remarkable fancy for grease in any shape or form for greasy horse-cloths, kitchen fat, and so on and nothing could be more interesting and instructive than the marked adaptation of its structures for the mode of life it adopts. Its habit is to feed by diving into the food-stuffs bodily. It is in no danger of being suffocated, for its breathing ap- paratus is arranged to prevent the fat from clogging its pores. Kitchen fat and horse-cloths are products of a more or less recent civilisation, and probably no one will deny that these larvae have acquired their peculiarities, enabling them to obtain food under such extraordinary conditions, at a period subsequent to the introduction of the fatty materials in question In a word the moths are a new species, evolved from ancestors which led different lives. To reject this 42 ROMANCE OF THE INSECT WORLD CHAP. opinion is to believe in their special creation for the purpose of relieving the world of a little superfluous fat. Another set of caterpillars (Galleridce) have a strange liking for wax, and to gain this substance force their way into beehives and the homes of wild bees, protecting themselves from the revenge of the lawful owners of the nests by spinning silken web around them in the cells of the combs robbers comparable with the Death's Head Moth. Ants indulge in a far stranger food of animal derivation a sweet liquid produced -by insects and often abstract it direct, warm so to speak, from the living body. The suppliers are aphides, or, according to their popular appellation, the plant lice or green fly, unhappily too well known in every flower and kitchen garden. On roses, ger- aniums, beans, cabbage, and fruit trees they multiply amazingly, and suck away the richest of the vegetable juices by means of a rostrum or tube, sometimes of great length, with which they are provided. Careful examination of a plant crowded with aphides seldom fails to reveal the presence of an ant, and it is not by chance that this member of the " little people" has wandered into the midst of the alien assembly. It has come with deliberate intention, to feast off a dainty and luscious .meal, a sugary, limpid, viscous secretion which is now and then exuded by the aphides, and denominated honey-dew. Ants, as a rule, do not wait to obtain it on the yielder's pleasure. One may be seen to approach an aphide, the extremity of whose body it rubs gently but rapidly with its antennae,* as if to entice the insect to ii FOOD OF INSECTS 43 accede to some request. The caress has the desired effect, for the aphide responds to the call by eject- ing a drop of liquid which the ant greedily laps up ; the aphide in fact acts as the ant's cow. No use of the secretion to the aphides themselves has been recognised; probably, since it is sticky, it is to their advantage to have it removed. This liquor forms the principal nourishment of many ants, of the red and - yellow kinds in particular, the different species of ants being chiefly devoted to different species of aphis. Towards the aphides of their choice ants extend special guardianship and protection, treating them as their own private property, and resenting on part of them all interference offered by other insects. Some take possession of a branch where their cattle browse, and hold it against intruders by vigorously attacking any aggressor. They serve as an efficient standing army to the aphides in return for the food that the latter furnish. Some ants build little walls of earth over their aphides, cow-sheds they may be called, to prevent them straying. Some form a private covered roadway between their cattle's grazing ground and their nest, placing their cows within easy reach and distance of communication. Others of these ingenious beings, who are always busy, have taken to heart the lesson of the necessity of the economy of time and labour. To save them- selves repeated and tiresome journeyings to and fro, they frequently thoroughly domesticate their cows, so to speak, or drive them in considerable flocks into the near neighbourhood of home ; sometimes 44 ROMANCE OF THE INSECT WORLD CHAP they convey them inside their nest. The aphides selected feed on the sap of grass and roots, a nutri- ment that lies ready to hand without troubling the captives to step out of doors, the subterranean chambers and corridors being constructed in the midst of the vegetation required. Formica show themselves good and attentive masters, and use their aphides with unvarying kindness and consideration. Ants actually breed their cattle, rearing them through the different stages of existence, hatching them out as though they were their own with the utmost care and tenderness. A fact has been dis- covered by Sir John Lubbock in connection with this habit, which he describes as one of the most remarkable he knows in the whole history of animal life. Certain aphides live not in an ants' nest, but outside on the leaf-stalks of plants. The wise and judicious cattle-breeders do not think of allowing the eggs laid by the aphides in the autumn to remain exposed to the severity of the approaching winter and innumerable dangers. They collect them and bring them into their nest, and the young are tended and fed and kept from harm by the ants until the fol- lowing spring, when they are carried again to the food-plants on which they were at first deposited. During all this period of watchful superintendence the aphides are not of the slightest use to their attendants, who receive no immediate return for their services. They lavish this care upon these insects with the expectation of future payment,: in order to have a fresh stock of aphides in the spring. In this way they secure adequate supplies of sweet liquid ii FOOD OF INSECTS 45 food, an instance of prudence and foresight unparal- leled in the annals of the animal world. Ants go similarly in search of the cocci* or scale insects, among them the valuable cochineal, and several Homoptera,* such as Membracis and its allies ; they are also intimately connected with a large variety of beetles. Many of these, like the aphides, live habitually with the ants ; at least between thirty and forty different kinds of beetles arc rarely, if ever, met with excepting in ants' nests. The reasons for the retention of these normal boarders are un- known. Many most curious functions have been assigned to them, but a considerable proportion of the co-habitants of the nest are in reality ant-cows. Claviger beetles at the base of their elytra possess tufts of tubular hairs which the ants take into their mouths and lick, and also the whole of the upper surface of the beetle's body, doubtless abstracting some special secretion that affords satisfaction to their palate. In return, the beetles are believed to be maintained at the expense of their grateful hosts. One quaint little claviger is blind, and is apparently quite a dependent, having lost the faculty of feeding ; at any rate it has never been seen to take refreshment alone, this is invariably administered by the nursing ants. For the most part, insects that feed on vegetables will not touch animal matters, and vice versa, but the rule is open to exception, notably as regards ants. Many caterpillars, though plants are their proper food, will occasionally exhibit depravity of taste, and if kept with their own kind, or with the 46 ROMANCE OF THE INSECT WORLD CHAP. larvae of other moths, may turn cannibal, and make away with the company. Similarly, the large green grasshopper will eat insects smaller than itself as well as its ordinary vegetable diet. The same may be said of young caddis flies, and of the mole cricket, which burrows in the earth, and feasts on roots. Should it meet a worm, or an insect, on its travels, it seems to see no reason to deny itself a little variation in its customary provision as a relief to sameness. On the other hand, some carnivorous beetles will make a hearty meal off a putrid fungus. One small family of this order (Dermestidse) in the larval state is a veritable plague in museums, attacking furs, skins, and dried flesh, and is not disinclined to enjoy bacon and ham. In the event of being unable to obtain anything of this sort, it has been known to pounce upon and ruin a ship's cargo of cork. It is a very remarkable fact that insects frequent- ly change their diet completely at their different stages of existence. Moths and butterflies in their immature condition feed on leaves and twigs, in the interior of trunks of trees, in roots, in seeds, or in the insides of fruits; while none when mature deigns to partake of anything stronger than a fluid, generally obtained by a casual choice and gentle sip from the honey-bearing cup of a lovely flower. In some parts of the world in the case of flowers want- ing in the secretion of free honey, these insects tear open the delicate succulent tissues in order to get at the sap; they rifle the juice from fruits, such as plums, peaches, and oranges, in like fashion. A greater change holds good for the various states of IT FOOD OF INSECTS 47 the Hymenoptera or Bee Family. As imagoes they are usually strict vegetarians, but during their larval period, while some live on plants the bees, sawflies, and others many are absolutely carnivorous, and can exist only upon living prey. It is customary for insects to provide for their own wants. A mother forsakes her young, leaving them to get on as they best may, but she takes care to deposit them in a spot in the midst of sustenance, or where it may be readily procured by the larvae. Some- times she goes on foraging expeditions, and stocks the larder of her infants with nourishment whether of a vegetable or an animal nature, sufficient for their consumption until they reach maturity. Some young, however, are incapable of feed- FIG. 3 . A honey-bearing . , . ^T M ant (Myrwecocystns Mexi- ing Without assistance. 1 hey FIG. 4. View of honey-bearers as seen in natural site clinging to the roof of a honey-room ; from McCook. or of colder temperature, harvesting ants have not been found. Perhaps the difficulties in the way of hoarding seed in good condition in the damp climate of Northern Europe would prove insurmountable. The food of European ants consists chiefly of insects and other small creatures which would not keep fresh, and of sweet secretions, vege- table and animal. Yet in a way European ants are provident, seeing that they can obtain a meal at will 58 ROMANCE OF THE INSECT WORLD CHAP. from the aphides and other ant-cows that hybcrnate along with them. Vegetable honey they have not learnt to preserve, probably because their young do not heed confinement in cells, like the larva? of the honey-bee. But on the whole the disproved maxim of the uselessness of storage of food by ants holds good of the English species, which succumb to sleep more or less, and require little or no nutriment during the cold winter months. When the sun is up, and everything is gay and bright, and around all nature seems quivering with eager motion and activity, we are apt to imagine that we see before us the whole population of the insect world. In reality a multitude as vast shun the glare of day, and, like the votaries of fashion, quit their couch and rouse into thorough wakefulness at the sober hour of twilight, when their more vulgar brethren have retired to rest. The "painted butterfly," the " fervent bees/' the " quivering nations" of flies, bask in the sunshine and search for food. But after the sun has sunk many moths emerge from hiding, the shard-born beetle with drowsy hum sallies forth, and numerous others of its kind ; and the gnats begin to wing their airy flight, and hunt down their living prey with a bloodthirsty and relentless ferocity, totally at variance with the aspect of things so fragile and so smalj. Some larvae too are night-feeders, but to the generality the time for food seems usually a matter of indifference, and they eat apparently with little intermission both night and day. In manifold variety of form the mouth or feeding apparatus of insects leaves that of all other animals ii FOOD OF INSECTS 59 far behind. It differs widely in the various orders, it differs in the families, it does not always remain constant throughout the lifetime of the individual, often there is an absolute dissimilarity between the mouth of the larva and that of the perfect insect. The mouth parts may, however, be broadly divided into two kinds : those made up of mandibles or jaws for comminuting food, and those forming a haustellum, or instrument for the suction of liquids without distinct manducatory organs. This difference of structure affords a natural opportunity for separating the Insecta* into two great tribes or sections the Mandibulata and Haustellata, or mandibulate and suctorial groups. It is possible to reduce the vast differences of the jaws and eating apparatus to a still more elementary basis of structure. From this point of view the mouth of an eating or mandibulate insect is very instructive. Take that of a beetle or grass- hopper. It consists chiefly of six parts, of which four arc lateral and disposed in pairs, the other two are opposed in the opposite direction, thus :': There is the labrum, or upper lip ; on either side are the first pair of jaws, or mandibles ; then come a second pair of jaws, the maxillae ; and finally, below the mouth is a lower lip, or labium, articulate with the chin-piece. The curved articulated appendages with which the maxillae and labium are externally provided are known respectively as the maxillary and labial palpi. In the jaws of many larvae, of a caterpillar for example, the form of the mouth-parts is almost precisely identical. The upper 60 ROMANCE OF THE INSECT WORLD CHAP. lip is well grown, the mandibles arc powerful, the lesser maxillae arc present, and behind these is the labium or inferior lip. And as in the beetle and grasshopper when they arc perfect, the maxillae and labium of the immature caterpillar are in general furnished each with a pair of palpi or feelers. Let metamorphoses go on, and the leaf-eating caterpillar becomes a sucking butterfly. A more pronounced example of the Haustellata tribe could not be given, and its dainty feeding organs seem to have nothing in common with the coarser apparatus of mandibulate insects, or with the early larval condi- tion of its own mouth. In a butterfly's mouth the only apparent structures are a more or less long slender trunk or tube, and two scale-like feelers or palpi situated below it. By removing the fine hairs and dense clothing of scales from the front of the head, a small transverse lamina* is seen, and its relative position determines it to be none other than the upper lip that was discovered in the caterpillar, although it is marvellously changed since then. Con- tinuing the investigations, a morsel of skin is observed on either side and beneath the lip, and judging, as in the previous instance, by position, the bits of skin are the remnants of the once strong biting mandibles. Beneath these is the conspicuous trunk, bearing at its base two small palpi, the presence of which leaves no room for doubt that the trunk is formed of the altered maxillae of the caterpillar. Below all is the labium, supporting large instead of the formerly small palpi. Examination thus reveals the fact that the three pairs of mouth-organs of the caterpillar are all ii FOOD OF INSECTS 61 present in the butterfly, though in a very different condition of form. This wonderful continuity of structure throughout the lifetime of a butterfly, in its change from a mandibulate* larva to a sucking perfect insect, shows that the mouth-apparatus of every insect, of the Haustellata and Mandibulata alike, is founded on the one self-same plan. The best " all-round " or typical development of the head and appendages is to be found in mandibulates, as a whole in the beetle family (Coleoptera). In Haustellata the deviation from the type is enormous, but it consists merely in the modifications of certain parts, which are more or less developed in each order in accordance with the general habits and instincts and modes of life. In mandibulates in the carnivorous and omnivorous families, whose habits require great strength, either in obtaining food or in the construction of their nests, the mandibles are the most important of the oral organs and the most largely developed. In Haustellata, whose food and modes of life are en- tirely different, the mandibles lose their importance and become atrophied, and their office, now altered in its character, is performed by the maxillae and labium. The development of these parts is so great that they have become almost or entirely the sole means of taking food, whereas in the higher forms of insects it is only of secondary importance. The transformations of the structures of the mouth of bees and flies are quite as wonderful. Into these changes we must not enter. Of the three kinds of insects, in fact of all insects without ex- 62 ROMANCE OF THE INSECT WORLD CHAP. ception, Lepidoptera hold the highest rank as regards special adaptation to flowers. They take little thought for their young, and the mouth has been free to adapt itself to the easiest possible winning of a floral liquid diet. Many perfect insects have similar tendencies as to food, but have been hampered with additional desires. The adapta- tion is attained by the astonishing development of the maxillae, to the almost total abortion* or suppres- sion of the rest of the mouth-parts. The atrophied condition of the now useless organs affords a beautiful illustration of the law that in proportion as the func- tions of an organ become suspended, or are not required, by the employment of other parts, the organ itself deteriorates and becomes useless, and perhaps entirely disappears. The maxillae are modified to take food in a liquid state, and still further the food is produced in ex- tremely inaccessible situations in the deep hidden chalices or nectaries of flowers. Thus they assume the shape of an elongated, slender, and flexible sucking-tube. Each maxilla is transformed into an immensely long rounded filament,* convex on the outer surface, concave on the inner side, and the tube is formed by the close approximation of the two organs. Throughout almost the entire length of both filaments one or more large tracheal vessels run, which are connected with the tracheae of the head. They divide into a number of minute ramifications as they approach the extremity of the organ, but have no communication with the external surface. The presence of these vessels has given rise to the idea II FOOD OF INSECTS 63 that each maxilla is hollow in its interior, for when the tube is cut across it is best to cut it towards the basal end it appears to be made up of three small tubes, two lateral ones encompassing a central tube between them. The inner or concave surface of the maxillae which forms the tube is lined with a very smooth membrane. In some species the extremity of each maxilla is furnished along its anterior and lateral margin with a great number of minute papillae arranged in two rows ; to judge from their structure and other circumstances, they may probably be regarded as organs of taste. Among other curious things the tube possesses some stiff, sharp-pointed appendages along the inner anterior margin of each maxilla, in the shape of hooks of marvellously small size. When the proboscis* is extended they are be- lieved to inosculate with each other, the hooks of the one side with those of the other, just like the dove-tailing of joiner's work, and to serve to unite together the two halves, so that they form the anterior surface of the canal. With this exquisitely simple mechanism butterflies are able to probe to the bottom of the most variously formed flowers, and to drain their honey. Not even the nectar of the long narrow bells of the Marvel of Peru or of the trumpet-shaped honeysuckle is safe from their pliant trunks, hidden treasure that they could never have had the opportunity of tasting had they retained the short and more primitive biting jaws. In the state of rest the tube is spirally coiled up like the mainspring of a watch in front of the head in small and convenient compass, and lies 64 ROMANCE OF THE INSECT WORLD CHAP. partly concealed and defended between the labial palps. It can be brought forward in an instant, straightened out, and darted downwards in obedience to the bidding of its owner. In regard to length it varies in the different genera and species, show- ing all degrees from the proboscis of the Bomby- cidae, that take little or no food, in which it is almost imperceptible, to that of Sphinx ligustri and the Humming Bird Hawk Moth of South America (Macro- glossa titati), the trunks of both of which are about two inches long. In butterflies and many of the Noctuidae they are about the same length as the body. The Sphingidse are remarkable for not alight- ing on the flower that they propose to rob, they poise on the wing before it, and rapidly dip into its well- like honeyed cups, without crumpling a petal. Having extracted its sweetest contents, they hasten away on their violent flight to another blossom. The manner in which the honey is conveyed by the trunk to the mouth has been explained to be by capillary* attraction. This opinion is probably in- correct, since the ascent of the fluid along the tube is not gradual and regular, as would be the case were it occasioned by this action. The liquid is as it were pumped from the flower, sometimes in full stream for one or two seconds ; then the motion falls off and becomes slower and slower, indicating distinct in- tervals between each draught or ascent of the fluid. The phenomenon appears to be due partly to the undulations and contractions of the sides of the tube occasioned by the action of its transverse muscles, which continue in action so long as the insect is feed- II FOOD OF INSECTS 65 ing. This agency is assisted in great measure by the lateral canals, or tracheal vessels of the organ. The butterfly at the instant that it alights upon a flower makes a forcible expiratory effort, by which the air is removed both from the tracheae of the proboscis and from those with which they are connected in the head, and at the moment of applying its proboscis to the food it makes an inspiratory effort, dilating the tube, and the food is carried along it quickly to the mouth to supply the vacuum produced, without any inter- ruption of the function of respiration. By this com- bined agency of respiration and muscular action, we can understand how a butterfly is enabled to extract in a moment the honey from a flower while hovering over it. This it certainly would be unable to do so rapidly, were the ascent of the fluid dependent on the action of the muscles of the proboscis alone. 1 Vegetable-feeding insects have little or no difficulty in procuring food. All nature lies before them, and unerring instinct is a guide that never fails or falters in directing them, by flight or foot, to the substance constituting their proper aliment. It is only under extraordinary circumstances, in face of the unwonted destruction of plants or when the numbers of these tribes are unusually increased, that they ever perish from starvation. The carnivorous species experience a harder struggle for existence. They are exposed to the dangers of deficiency and deprivation, but fortun- ately they are frequently endowed with the faculty of enduring long abstinence. The kind of food they take leads them to employ a variety of methods in supply- 1 Newport. F 66 ROMANCE OF THE INSECT WORLD CHAP. ing their wants. A large proportion attack their prey by open violence, which is a clumsy and unsportsman- like mode at best. Or they surprise insects by hiding behind a stick or stone, affording concealment until their approach. The predacious hypocritical " praying Mantis " so called because the posture that it assumes is supposed to resemble the attitude of a person at prayer feigns sleep or death. But a few species have acquired far higher art in providing their susten- ance. They have recourse to artifice and strata- gem. This is in itself a fact of great singularity, and the instruments by which these carnivora take their prey are admirably adapted to the end in view. The Ant-Lion (Myrmeleo fonnicaleo) may be adduced as an interesting example. It is endowed with little talent as far as its powers of body are concerned, but that which it has it turns to good account. As a larva it is wholly carnivorous, and shows preference for smart able-bodied insects. Besides it is an epicure, spurning all food, however great its hunger, unless it be fresh caught and killed, so to speak by its own hand. To look at it one would laugh at its pretensions to sport. In form it is short, flat, squat, and excessively clumsy, its body is soft and fleshy, its motion is sluggish, its legs are slender and feeble, its pace is absurdly slow ; moreover, it can merely walk backwards. What luck could this creature have in the chase ? Neither could it succeed in obtaining food by lying in wait for its prey exposed since its jaws are so ferocious in appearance as to incline every insect to give it respectful berth. Its II FOOD OF INSECTS 67 object is to conceal itself, to do which it adopts a well-laid plan, for though it appears inert and help- less it is no bungled performance of nature as some foolish persons would have us to believe. On the contrary, its structure is exactly what is required to render it competent to capture living and active delicacies. Choosing a fine light sandy soil, little exposed except to the sun, and generally in the neighbourhood of trees where ants are likely to have set up house, the Ant-Lion vigorously proceeds to construct its snare. It begins by pushing itself backwards in a circular direction so as to trace a shallow furrow vary- ing from one to three inches in diameter. A succession of these furrows is formed one within the other, each being of course smaller than the previous one, and the larva with its broad shovel-like head scoops up and throws out the sand beyond the limits of its precincts. By this means a conical or funnel-shaped pit is at last completed, of no great depth but with very loose sides. The insect's labour being over, it ensconces itself at the bottom of the trap in the sand, leaving its enormous jaws alone exposed and widely extended. Here it sits in crafty motionless vigilance, in wait for what may come. Ants, like monkeys and children, are distinguished for an insatiable curiosity, and should one spy the cavity when it is abroad on the out-look for food it would never hesitate to approach the edge. Its satisfaction seals its doom. It gets a glimpse of the ogre, and in vain it endeavours to retreat, for the treacherous sand gives way beneath its weight, and the hapless thing F 2 68 ROMANCE OF THE INSECT WORLD CHAP. goes rolling down into the greedy outstretched jaws of the fortress's Giant Grimm, and a sharp bite soon puts an end to its existence. In a short time it is sucked dry, and the dead and withered carcase is flung from the pit, with an odd jerk of the Ant-Lion's head, in order to leave the trap unen- cumbered and ready for future conquest. The victim does not tamely resign its life to its captor without attempting to save itself. A plucky ant is incapable of cowardly conduct of the sort. But it will be readily perceived that the more frantic are its endeavours to elude its fate by scrambling, the greater is the displacement of the yielding sand, its movements become more and more impeded, it is overpowered, and slowly but surely driven within reach of the murderous jaws. That the Ant-Lion in- tentionally aids in bringing about the result by dashing showers of sand at the struggling insect is probably somewhat of an exaggeration, for one can hardly credit it with flinging the pellets with any definite aim. The captive in its struggles must cause a quantity of sand to fall into the pit, and the larva feeling its house tumbling in, instinctively tosses it out. Some of this may hit the ant, and in that case will certainly bring it nearer the jaws. Naturally should a large and unwary hunting-spider, a wood-louse, or perhaps a beetle, pay the penalty of inquisitiveness and fall down the hole, the fight between the snarer and its prey waxes fiercer and more prolonged. These prisoners have no idea of surrendering at discretion. They are sore at their own folly, indignant at being betrayed, and in their II FOOD OF INSECTS 69 furious exertions to find release they send down the sand in torrents, which fills up the pit, rendering its sides far less steep and therefore easier to surmount, for a powerful insect is better able to withstand such an avalanche than a tiny ant Then ensues a battle royal, the one opponent fast bringing down the sand which the other as determinedly ejects, being bent on keep- ing itself free and on restoring its house to its pristine neatness. Sometimes a load flung by the Ant-Lion strikes the retreating creature unawares, and it loses its balance never to regain it, giving the larva just the opportunity that it needed to grasp it in its terrible sickle-shaped mandibles. Sometimes the captive becomes exhausted before the Ant-Lion and allows itself to be caught ; and sometimes, though rarely, the onslaught ends in victory on the former's part, and it succeeds in making good its escape. In any case the pit has suffered such damage that its owner does not spend time on rearranging and repairing it, but abandons it, and starts on a fresh series of excavating operations. In this manner, burrowing in the earth and catching living prey, the larva lives until it is full-grown and fed. The early immature period lasts for about two years. It then retires under the sand, and spins a cocoon of silk mingled with sand, and after the lapse of a few weeks is transformed into the winged and perfect state. The adults are not in the least like the larvae. It would be hard to conceive a more complete contrast, and were the two forms placed side by side no one unacquainted with the circumstance would believe them to be but two stages of the same insect. 70 ROMANCE OF THE INSECT WORLD CHAP. n. The perfect Ant-Lion is very elegant and handsome, of a dark grey colour with yellow spots. Its large transparent wings, four in number, are ornamented with black marks. In appearance, in fact, it bears many points of resemblance to the dragon-fly. CHAPTER III HERMIT HOMES Methods of formation of homes constitute remarkable phase of habits and economy of insects A home necessary by reason of nature of life of insects Habitations of solitary insects for their young Solitary bees Solitary wasps Galls Habitations of solitary larvae for own use Homes of solitary architects being perfect insects for own use and also for that of their young Trap-door and other spiders, OF all the phases of the habits and economy of the insect world, none present more remarkable pecu- liarities, and are calculated to arouse deeper feelings of interest and appreciation, than the methods that these little beings employ to provide themselves with homes. We regard with admiration the architecture of the nests of various birds, we yield the palm to the villages of the beaver among the structures of quad- rupeds, but for the acme of indefatigable industry, perseverance, and ingenuity, we must look to the habitations of the tiny insects. The very nature of an insect's life renders a home more absolutely neces- sary to it than to almost any other creature. During all its immaturity, to leave its perfect stage entirely ROMANCE OF THE INSECT WORLD CHAP. out of the question, it would obviously be particularly open to dangers of weather and natural enemies. But here the most powerful of its instincts steps in to its aid, the instinct that has for its object preservation of the species. Gifted with what seems almost mira- culous foresight, many in- sects, at the expense of incalculable labour, prepare a home, comprising not only an abode but a store- house of food, where their offspring, which they may or may not be destined to see, and whose habits are entirely unlike the parents', may in safety, as complete as possible, pass through the whole series of infantile helplessness, and emerge from it to take their place in and cope with the world, only when they have at- tained to the perfect form. This instinct is in other cases exercised by insects for their own accommoda- tion, for their larval, pupal, or imago conditions ; the habitations being merely refuges or shelters, or afford- ing board in addition to lodgment. For these purposes .some burrow subterranean galleries in the ground, some FIG. 5. Profile view of nest of a Mining Bee {Andrena vicina, Smith), which builds her nest in grassy fields, (a) Oldest cell contain- ing pupa ; (b b) cells containing larvae ; (c) cell containing pollen-mass, and e gg ; GO the most recent cell con- taining a freshly deposited pollen- mass ; (e) the beginning of a cell ; (/) the level of the ground ; from Packard. in HERMIT HOMES 73 excavate different parts of vegetation, some build houses of mud, clay, or sand ; some of leaves, bits of stick, grass and shells ; some roll up leaves with art- ful care, and dwell therein; some construct homes of excretions from their own bodies. In fact, the variety of these admirable contrivances is nearly infinite ; and many for proportionate size and solidity, in com- plexity of arrangement, and the complete manner that they subserve the intention of formation, may very well be compared with the structures of reasoning man himself. In this chapter it is proposed to deal with the habitations of insects living in a state of solitude, and built each by a single individual, leaving the social communities which unite in the labours of construc- tion to be dealt with later on. The latter class are better known, perhaps, because they are more strik- ing on a general view ; but intimate acquaintance with both leaves it a difficult matter to decide which kind exceeds the other in wonder and attrac- tiveness. We are all acquainted with the proverbial busy- ness, the arrangements and policy of the ordinary hive bee, for the care and rearing of its young. With like object, and carried out with incomparable art and activity, are the homes of many of its wild and solitary relatives. Among these bees there is no special laborious worker,* and since the male is an equally idle member of society as the drone of the hive, the duty of providing for the wants of the future brood devolves solely on the mother. Awakening from her winter sleep, she loses no time in fulfilling 74 ROMANCE OF THE INSECT WORLD CHAP. her mission. She has to select the site of the house that is to be, and to fashion it; to discover and collect nourishment, and stock it in her cells, in quantity sufficient for the proper development of the larvae, no less and no more, but just enough. She lays her eggs, and shortly after dies. If any fighting with enemies has to be done while her operations are in progress, she it is who does it, so her position in life is no enviable sinecure. A group of these bees is popularly called the Miners, a name fancifully bestowed upon them by Reaumur to indicate the character of their labours. They are little creatures (Andrena), but in spite of diminutive proportions they are admirable burrowers, driving their tunnels into the ground or masonry to a depth of eight or ten inches. The soil they select is often hard, such that an ordinary pocket- knife makes no impression upon it, as a well-trodden pathway baked by the sun ; occasionally they choose loose sand. Usually the burrow is dug in a perpen- dicular direction for several inches, when it takes a sudden turn, and forms a rounded chamber. Here the bee deposits a store of pollen * mixed with honey, and lays a single egg. Creeping outside she closes the orifice securely with the material she has expelled in excavation, leaving the egg to hatch and the young to come to maturity and escape in due season. Some members of this genus, and of Halictus, save themselves the trouble of making a number of separate burrows. They add short sup- plementary chambers, not more than an inch or so long, from the sides of the first and main shaft, and in HERMIT HOMES 75 opening into it. In each is placed an egg and its food. All the inmates, therefore, though they lie secluded one from the other, emerge from their nursery, when their time comes, by a common entrance (see Fig. 5). The Carpenters are solitary bees so called from the circumstance of their working in wood ; technically they are termed Xylocopa, a word that literally means a " wood-cutter." As far as we are aware, none of the genus are indigenous to this country, but they are scattered over all the warmer regions of the world. A trunk or branch of a tree answers their purpose, and they are particularly partial to old posts, or wood railings, and to the wood-work of houses which has become soft, because beginning to decay. They are never averse to adopting any ready- made hole that they may come across, provided it is not too large; they even refurbish up old nests deserted since a former season's occupation. Xylocopa violacea may be taken as typical* of the race, a lovely creature, larger than the largest humble-bee, with brilliant blue-violet coloured wings and a black velvety body, a native of Southern Europe. The female appears in the early spring, and at once seeks a spot to commence her arduous undertaking. Its selection is evidently a matter of moment and con- siderable time is spent in repeated and thorough investigation ere she fixes upon the wood. An upright piece is usually decided upon, and with her powerful jaws she begins a severe process of boring. For about the depth of an inch she works obliquely down- wards, suddenly the course is altered, and she 76 ROMANCE OF THE INSECT WORLD CHAP. proceeds perpendicularly and parallel to the sides 01 the wood, until a tunnel is sunk, of a length no less than twelve or fifteen inches, and perhaps half an inch wide. As though this remarkable exploit were not enough, where the diameter will admit of it, some- times three or four of these cylindrical tunnels are excavated side by side, a task which takes several weeks of incessant labour. One would judge the nest to be now complete and ready for the progeny ; but no, much more remains to be accomplished. It is necessary for the proper development of the offspring that each should have a separate apartment, and be supplied with its appropriate quantity of food. Having finished the bore to perfection it is made absolutely clean, and smooth, and regular, as though chiselled by a joiner and having deposited a single egg at the bottom along with a ball of pollen and honey, the bee covers this over with a ceiling at the height of nearly an inch up the tube. Where, you may ask, does she obtain her material, and how is this partition constructed ? During her excavation, the quantities of fibres detached were carefully stowed away in a neat little heap at a short distance from the nest, and sheltered from the action of the wind. Here then is the wherewithal that she stands in need of. With particles of this sawdust, cemented together with her own natural glue and to the sides of the tunnel she lays the foundation of the partition in the form of a narrow annular ring. Being hardened, it affords support for another ring along its interior edge ; thus the orifice is gradually contracted, and is Ill HERMIT HOMES 77 closed with a circular plate. Though the mass is made up of these fragments, it is almost flat and solid, and exhibits the appearance of as many con- centric circles as there have been pauses in the work. It looks not unlike the annual zones in a cross-section of a tree, or a slice cut through the FIG. 6. Nest of an Australian Carpenter Bee (Lesfis bombylans). middle of an onion. This, the ceiling of the first cell, serves as the floor of the second. In the latter apartment another egg is lodged and is furnished with nourishment, and receives a ceiling. In this manner the bee continues until the hole is divided into ten or twelve chambers, each with its egg and pollen ROMANCE OF THE INSECT WORLD CHAP. (see Fig. 6), when she closes the entrance, shutting all well in lest the contents should fall victim to some unscrupulous enemy. Obviously a considerable interval of time must supervene between the laying of the first and the last egg, while the bee is engaged in the herculean labour of building up the various successive cell-partitions ring upon ring, particle by particle and in pro- visioning the occupants of the intervening cells, involving long toil and diligent search. Naturally the lowermost egg must turn into grub, and pupa, and perfect insect, long before that finally deposited. What then becomes of it ? Its mandibles are not strong enough to pierce a passage out through the wood. It is impossible that it can gnaw its way through the eleven superincumbent cells to the original entrance without damaging their immature inmates ; and equally impossible that it can remain imprisoned till they one and all have effected their escape. The mother provides against this con- tingency. She constructs not only one point of access to her dwelling, at the farther end she likewise makes a lateral horizontal opening, a kind of back- door, and chokes it with sawdust paste, which being soft will readily yield to the tender jaws of her offspring. Through this door the first-born emerges into day, as in fact does each insect, one after the other in succession in priority of development ; for by an exquisite arrangement, every grub when about to turn to pupa places itself in its cell head down- wards, and thus in a position eventually to break- open the cell in that direction. ih HERMIT HOMES 79 The Mason bees of Reaumur belonging to the genera Osmia and Chalicodoma are remarkable for the singular variety of their architecture, or it would be nearer the truth to say that they are gifted with remarkable power of adaptation to circumstances, and vary the details of their operations, through all of which runs one undeviating plan. Their structures are elaborate, and they exercise peculiar care as to the materials used, each species selecting a particular substance ; the site of the home is also subject to much fluctuation. Differing from all others this applies especially to the Osmia in having their hind legs unsuited for the gathering of pollen, they achieve the collection of food by a multitude of stiffish hairs on the rings of the lower part of the abdomen. One of the commonest mason bees, the large and massive Chalicodoma muraria, or in plain English the " stone house," a name derived from its building capabilities, is a builder in the ordinary sense of the word, for its homes are not of the more primitive burrow type, but are erections and of true masonry. On a rock, or stone, or wall of sunny aspect, they may constantly be seen, irregular, oblong, or egg-shaped masses, looking to the casual observer like so many splashes of mud which had been thrown against the wall and had become hardened. Suppose the bee to have chosen the site of her future dwelling, as with all others a matter for deliberation. Off she flies to a spot where suitable building-stuffs are obtainable, and with her mandibles collects sand and small stones, and glues them with her viscid saliva to 8o ROMANCE OF THE INSECT WORLD CHAP. a few grains of earth, adding little quantity to little quantity until a pellet is cemented, the size of small shot. The ball of mortar being formed, is borne off in her jaws and fixed on the place determined. When she deems sufficient material laid she mixes all the earth, and completes a cell about an inch long and half an inch broad. She enters and anxiously smooths FIG. 7. Clay nest of a Solitary Wasp (Eumenes) in early stage ; from Natal. it, she stocks it with a cake of pollen and honey, and lays an egg in the midst, then it is walled over. Other cells are similarly erected close by, up to the number of twelve or more. Their order of deposition is not regular ; they may be parallel to the founda- tion, perpendicular to it, or at every conceivable angle of inclination. The building is not yet finished, for the group receives a sort of roof or in HERMIT HOMES Si general covering, composed of coarser grains of sand than those hitherto entering into the composi- tion. One more provision must be made for the well- being of the precious sojourners. A crevice that was left open from each cell to the exterior surface when the final wall was added is now stopped up with rather soft sand, easily penetrated by the feeble jaws of the young. These bees appear to keep a sharp look-out for the ruins of any last year's nests that afford possibility of repair, and re-making as good as new. Finding an old home they go vigorously to work upon it ; the cells are swept clean of all debris that has accumulated the skins of larvae, cocoons, and what not any holes and imperfections are attended to, and the chambers victualled and closed up. Laziness even brings the masons to dishonesty. They will unlawfully intrude into a house in course of erection, the possession of another, and fight desperately to re- tain the prize. Some Osmiae adopt the simple and less onerous plan as compared with the labours of Chalicodoma of placing their cells in decaying wood, or in the stems of the blackberry, the rose, and other shrubs, or within straws, as the industrious and tiny Chelostomes. One species merely attaches a number of balls of pollen, each with an egg, to the under sur- face of some flat stone. The larvae when full-fed spin their cocoons on the spots which the pollen balls pre- viously occupied. Osmia bicolor, a species indigenous to southern Europe and found in England, utilises abandoned shells of garden snails as ready-made burrows. Strangely enough, the last laid eggs, in the G 82 ROMANCE OF THE INSECT WORLD CHAP. cells at the mouth of the shell, produce males, which are developed before the female insects, who inhabit the end of the whorl. The females therefore pass out through the deserted male premises above them. The Megachile are celebrated for the beauty and singularity of their nests. This is the most cosmo- politan of all the genera of bees ; numerous alike in the tropics and the colder latitudes, extending as far northwards as Hudson's Bay. Their peculiarity, whence is derived their generic title, literally signi- fying " large-muzzled," lies in their long and powerful mandibles, and with these instruments the species dubbed the " Leaf-cutters " perform the clever feat that their name implies. Under the popular term are included the British and all the known European specimens. These agree in the habit of making curious burrows for their young, in the earth or in wood, lined with cuttings of leaves, or the petals of flowers, abstracted from plants with wonderful pre- cision and accuracy. M. centuncularis, a little bee, is endowed with striking intelligence, though it is by no means remark- able to look at, like many another clever creature, for Nature, it would seem, is ever loth to cumulate her choicest gifts, and generally balances any lavish sup- ply of blessing, physical or mental, by corresponding deprivation of the quality opposed to that bestowed. The bee usually begins, but she is capricious in choice of site, by excavating a cylindrical tunnel in tolerably solid earth. It is bored in a perpendicular direction for a few inches, and afterwards enlarged into a horizontal chamber of good size. Within the in HERMIT HOMES 83 latter, starting at the bottom and progressing up- wards, eight to ten cells are constructed, composed entirely of portions of leaf, like a file of thimbles, the small and convex end of each fitting well into the large and open mouth of the cell previous. Ten or twelve pieces of leaf of different shapes are cut and carried to the bottom of the gallery, and there twisted and folded one within the other, so as to form a pretty funnel-shaped cone from a quarter to a third of an inch long, narrower at the closed extremity than at the orifice. The pieces are always placed so that no two joinings come together, the middle of one scrap lies over the margins of two bits immediately below, strengthening the whole fabric. Making up a ball of pollen and honey the bee places it inside, and with it an egg. Once more recourse is had to the rose, and a fragment of leaf is taken off so exactly circular that a pair of compasses would not do it more nicely, and of a diameter fitting precisely the cell's mouth. Into this the morsel, is thrust with its convexity turned downwards ; a second piece, a third, sometimes a fourth, are added, to obviate the faintest possibility of oozing of the honey. The slightly concave surface of this lid receives the follow- ing cell which is completed in like manner, and gradually the series is built up. All being finished, endeavour is made to hide the entrance to the shaft with the earth expelled to form it, and to such good purpose that no trace is left of this marvellous work. The bee, to obtain her building material, rests firmly on the edge of a leaf, usually so that it passes between 84 ROMANCE OF THE INSECT WORLD CHAP. her legs. With her strong mandibles she quickly cuts out the roundish portion she requires, as with a pair of scissors, turning upon a pivot with her feet ; and lest its weight should carry her to the ground, just before the last fibre is severed she balances her- self in the air for flight, and at the moment it parts bears it off in her jaws in triumph. Anthocopa papaveris, the " abeille tapissiere" ol Reaumur, as though fascinated by the brilliant colour, fixes its choice of cell-lining upon the common scarlet poppy. It is small, of a velvety black, ornamented with white downy hairs on the margins of the segments of the abdomen. Its burrows are perpendicular holes in dry and sandy soils, perfectly cylindrical at first, but swelled out below in the shape of a Florence flask. The sides the bee stamps firm and smooth ; then portion after portion, to the number of three or four layers, is cut from the poppy, each morsel as it is introduced into the cell being pressed and straightened against the walls, to take out every curl and wrinkle from the delicate tissue. The honied provision and the solitary egg being committed to this cosy apart- ment, the upholsterer carefully folds in the free ends of the petals, a necessary precaution owing to the nature of the soil, to prevent the encroachment of the grains of sand. This done, the rest of the hole is stopped with earth. Some of the exotic * species of Megachile, as M. lanata and M. disjuncta, common to India, form tubes of agglutinated particles of sand or clay independently of a burrow. They also fill up the hollows of tree-stems with clay cells, instead of a Ill HERMIT HOMES lining of leaves, built end to end in long lines, but with very little cohesion. The tenacity with which the clay adheres to the wood, however, is remarkable, and probably it is inspissated with some glutinous substance ejected by the insect. Equal in interest to the nests of bees, and con- structed with similar purpose, are the homes of many solitary wasps, and other so-called Fossorial * Hy- menoptera. However well-defined so far as external characteristics are concerned, the families have many mutual resemblances in their habits of life, though each species has its own particular fancies as to site of home, and food, and other details. Like bees, in the adult state they live on honey and such-like vegetable fluids, but the larvae are flesh- feeders, and we see the curious and suggestive sight of non- carnivorous mothers chasing and bringing down insect prey for their carnivorous offspring. One point in connection with this feeding deserves special mention the young must derive their nourishment not merely from animal substances, but from actual living tissues. Inert, unarmed, unable to help themselves, or to move from the spot where they are hatched, how can they ever have living insects in their power ? the difficulties to be paved away seem insur- mountable. Nature holds a fairy wand ; it is FIG. 8. Pelopseus Wasp building nest ; from Bates. 86 ROMANCE OF THE INSECT WORLD CHAP. the mother who provides for them. In captur- ing insects she does not kill them, she inserts her venomous sting in her victims, producing a long, indeed a fatal, lethargy,* for the poison seems to preserve the unfortunate creatures from death and decay. In this condition she carries them to her cells, in this condition they lie, condemned to be slowly eaten by the hymenopterous larvae. Let us hope kind Nature deprives the luckless beings of consciousness in the same moment that they are robbed of animation. The Fossores belonging to the genus Odynerus, or the False Wasps, are pretty little black things, striped with yellow, noted for their agility and graceful movements. The Masons of Reaumur may constantly be seen in this country in great numbers, flying to and fro over a hard, sandy, or gravelly bank exposed to the sun, boring their tunnels and storing them often with the green larvae of a weevil,* of which as many as fifteen or sixteen may be put in one cell. They raise a fanciful cylindrical tube over the mouth of their burrow ; when finished, it often projects from the soil no less than two or three inches. It is formed of pellets of earth arranged in circles one over and in front of the others, with small intervening spaces left open between the masses, giving it the appearance of filigree work. For the greater part of its length it is upright, but towards the top is carried downwards to describe a slight curve. The use of this vestibule is doubtful ; perhaps it may prevent the incursions of artful parasites, who may fear to enter so long a defile. Whatever the object tit PERMIT HOMES 87 may be, it is a temporary one. Present only while the victualling is going on, and the eggs are laid, subsequently this entrance to the gallery is pulled down, and constitutes the material that goes to fill up the lip of the hole. Eumenes coarctata, the only British example of its genus, an odd-looking wasp, has the first segment of its abdomen drawn out to form a decided foot-stalk, so that the abdomen appears joined to the thorax as by a bit of fine black wire. Its nests are small, globular, and vase-like, built of mud, and fastened to the stems of various plants, the common heath being the greatest favourite. Each contains one cell, and is the habitation of one occupant. E. pomiformis affixes her nests to walls. E. petiolata, conica, and esuriens, Indian species, seem to prefer the wood- work of houses, such as door- and window-frames and posts, and, where the locality is suitable, some- times a succession of cells will be constructed side by side, often more than a foot in length. The nest of petiolata is the size of a pigeon's egg. Whatever the exigencies of the situation, the Eumenes strives to retain the spherical form of the edifice and the recurving brim (see Fig. 7). The Sphegidae, Pompilidae, and Bembecidae, are popularly classed together as the Sand-wasps. As their name denotes, they love to form homes in sandy earth, where they lay eggs, and stock them with living insects, rendered powerless by their poisonous stings. The well-known Sphex, the typical genus of the Sphegidse, is scattered over the greater part of the world ; the English species there is but one is ROMANCE OF THE INSECT WORLD CHAP. somewhat common in the eastern counties. Am- mophila afford an excellent instance of the ordinary manner in which these insects prepare their burrow. It consists of a long, narrow gallery, opening into an enlarged chamber, a formation calculated to enable the mother, after storing the prey she has secured, to regain the surface. She descends into the tunnel backwards, dragging her burden after her, and were it the same size in every part, there would be no room for her to creep from under the food, and to pass out. The genus Pelopaeus are inhabitants principally of warm climates. Many are excellent masons, and may be watched at muddy puddles, kneading and rolling up clay into spherical pellets, and carrying them off in their mandibles to form the future residences (see Fig.. 8). The oddest spots imaginable are often chosen for their sites. Sometimes a cell is separately constructed ; sometimes one is placed over another ; but generally the nest is composed of a number of cells, built side by side upon the same horizontal line, each being filled with food and closed as completed. The whole is covered exteriorly with a smooth coating of mud. The mothers are bold and fearless hunters, and think little of attacking strong and well-armed spiders. Doubtless their sting is a terrible weapon, and when once the enemy is struck, taken unawares it may be, all is over. But the spider, if on the out- look, sometimes manages to cast its web-threads over the Pelopaeus, and paralyses its movements ere the fatal arrow is shot. Soft plump spiders, one would naturally think, would be chosen by the wasps. lit HERMIT HOMES 89 But in tropical America P. fistularis culls those be- longing to a large group allied to our common garden spider, all possessed of hard shelly polished cover- ings, not even smooth, but shooting out into the most fantastic and formidable projections. The genus Pompilus rival the Sphegidae in bravery and cunning in catching prey. They also provide spiders for their larvae, mostly wandering kinds which never make webs. In this country where about twenty species of Pompilus are known, they are of small size and unimposing. In another class of habitation for the young the homes serve in the dual capacity for the shelter and the sustenance of the occupants, and though they spring from the mother's work they rise independ- ently of her construction. It will be understood that we speak of galls, vegetable excrescences that we all know well. They differ in appearance, shapes, and sizes, and affect multitudes of plants, though the oak is especially prone to the attack. All parts of the plant are infested by them, the leaves, the buds, the trunk, the twigs, even the flowers, the fruit, and the root. Every one has observed these abnormal growths, but comparatively few persons are acquainted with the insects to which they owe their origin, and with their young, for whose early up-bringing alone they exist. The Hymenoptera that produce galls constitute a group by themselves, the Cynipidse, which contains the genus Cynips, and others very much like it. Though they vary greatly, a striking family re- semblance runs through them all. They have an 90 ROMANCE OF THE INSECT WORLD CHAt>. oblong and very convex body, and the female is provided with a peculiar apparatus for egg-laying, the ovipositor, a slender hair-like ' tube, which when not FIG. 9. Galls of Cynips insana, or Dead Sea Apples. in action is coiled up, spiral fashion, within the abdomen. During spring and summer, when vegeta- tion is in full sap, is the time for depositing the eggs. Having selected a proper spot, the "fly" straightens in HERMIT HOMES 91 her ovipositor and thrusts it instantaneously into the leaf or other object, making a puncture, subse- quently widened by -boring. Into the hole she drops one or more eggs. To conclude, she spreads a slight quantity of secretion over the wound, so irritating to the plant's tissues as to alter their nature, and de- velop, but how we know not, the irregular swelling of the cellular structures that we term a gall. Midst the fleshy chamber thus constructed the eggs are hatched, and the larvae live on its interior. The insects remain within the galls until they have under- gone all their changes, and emerge, eating their way out into the open air, upon their attainment to the perfect form. Others escape as larvae, and burrow into the earth for their later metamorphoses. Forty-two or more kinds of galls occur on oaks in Great Britain alone, but the damage done to the trees seems almost immaterial. There are the familiar oak-apples, arranged usually several together in small clusters on the twigs and branches, irregular in shape, and sometimes of enormous size, the work of Cynips terminalis. These contain an aggre- gation of cellules, twelve to fifteen or more, the hermit habitations of solitary larvae. From the separate cells a fibre, as it were, runs towards the base of the gall. Probably these fibres are the nervures of leaves which would have sprung from the bud in which the eggs were laid, had not the irritating fluid caused them to develop in a new manner. The well-known small oak-apples found in profusion on oak leaves are due to the puncture of Cynips quercus folii. Well they deserve their popular 92 ROMANCE OF THE INSECT WORLD CHAP. title of cherry-galls, being beautifully coloured, some scarlet, some white, some red and orange, in various gradations. Their surface is smooth and brightly shining; in substance they are of a soft pulpy consist- ency, not unlike a gooseberry or hot-house grape. In the centre of the mass is a solitary globular chamber containing a single larva snugly curled up. The undersides of oak leaves are also infested by small, flat, round, disc-like bodies, the common spangle galls of the Neuroterus lenticularis. They sometimes occur in such quantities, but rarely, as to weigh the leaves and cause premature withering. The elegant so-called currant galls that depend on slender threads from the oak's catkins resemble sparse bunches of currants. Their colour is another reason for their name, for they are sometimes scarlet and sometimes white. The Rose Bedeguar, or Robin Redbreast's Pin- cushion, frequent on hedge-roses and sweet-briars, is formed by C. roses, an insect about the fifth of an inch long. She deposits her eggs towards the end of May or beginning of June, with the result of great swelling of the stem, while the leaves are produced in ordinary numbers but without cellular* tissue between the fibre-vascular* bundles, causing the exterior of the fungus-like growth to be covered with numberless many-branched, hair-like filaments, the so-called " moss." These galls attain their full size on the approach of cold weather. How pretty they look at the close of summer tinted with green and red. When winter ultimately sets in, they lose all brilliancy and become uniformly in HERMIT HOMES 93 brown. Although the soft compressible moss-like surface appears to form the whole of the gall, in reality there is a dense woody tissue, within which lie the larvae admirably protected against injury from without. The number of cells in a Bedeguar is mostly great. They are usually restricted in size ; larger dimensions seem always obtained at the ex- pense of solidity of the walls. Each cell contains a single egg, and each in its own restricted space the larvse are hatched. In this stage they remain quietly at rest for the winter, quickly changing to pupae and the perfect forms at the beginning of the following spring. Should the spring be cold the " flies " do not at once desert their home on the completion of their metamorphoses, but await the arrival of propitious weather. Then they gnaw their way through their abode and escape. The gall nuts of commerce, or Aleppo galls, used to make ink and tinctures and whence gallic* acid is derived, affect the leaves and twigs of an Eastern species of oak (Quercus infect- oria*}, abundant in Asia Minor and Turkey. They are remarkably hard, and almost spherical and tuber- culated.* Their juice may be said to be colourless, but if it is mixed with a solution of the sulphate of iron or copperas, itself very pale green, the two com- bined produce a fluid intensely black, such as the ink in common use. Any one may prove the fact for himself, and manufacture ink on a small scale, by cutting some succulent British gall with a steel knife, and he will find his fingers stained as with pale ink by the action of the iron on the moisture of the gall. 94 ROMANCE OF THE INSECT WORLD CHAP. The so-called Dead Sea fruits, apples of Sodom, or Mala insana (see Fig. 9), grow on dwarf members of the same oak on the borders of the Dead Sea. About them strange stories have been told, and their nature once aroused controversy amongst commentators upon Biblical and Oriental literature. Travellers use to describe these Dead Sea fruits that tempt the eye, But turn to ashes on the lips ; beautiful to look upon with their glossy deeply- purplish red surface, and as large as good-sized apples. But when tasted, instead of the sweet juicy substance one was led to expect by the lovely exterior, they filled the mouth with bitter dry ashes, drawn, so it was said, by the oak from the ruins of three evil cities buried beneath the bituminous waves of the Dead Sea. Hence the " fruits " were tangible evidence of the cities' former existence. For many a day this story was believed ; at length it was dismissed, the very existence of the " fruits " was denied as the inven- tion of an Eastern fable, in spite of plain allusions to the contrary by Josephus, Strabo, Tacitus, and other ancient authors. Recent research proves the main facts of the case to be correct; the inferences deduced fare badly. These " fruits " are galls of a Cynips named by Westwood insana. They do not belie the old descriptions of their beauty, and natur- ally they are astringent, more especially as they grow upon an oak. Doubtless they will prove sufficiently so, if any one care to make the test, as to warrant the tales of the rough and ash-like in HERMIT HOMES 95 sensation they produced on the palate in the days gone by. Cynipidae are not the only insects that originate galls. In the beetle group some of the weevils pass their early stages in swellings brought about by the parents. The Cecidomyia in the order Diptera, the saw-flies, the aphides, the moths, and many more are likewise gall-makers. No form of habitation can be simpler and more natural than the burrow, and when it is made in seeking for, or in eating, food, the point seems to be reached at which simplicity of design can go no farther. Many an insect that to see is to admire fragile, beautiful in brilliant colour, soaring in the air, exulting in the sunbeams indebted to its own exertions, has passed the previous portion of its life thus hidden in the interior of a tree trunk, a branch, a leaf, or a root, even in fruit or in the earth, feeding greedily on its surroundings or upon any prey that might come within its reach. In these con- cealed situations it has entered upon its etherealised winged state, and become equipped for its higher position and purer atmosphere. Of this nature are the homes of the larvae of one of the wasp-like moths, Sesia apiformis. These cater- pillars are pale in colour, and at a glance one judges them to be wood-eaters. The eggs are laid on the bark of poplar trees, and when hatched the young at once make their way into the interior of the trunks, and eat out tunnels of considerable size for no less a period than two years previous to their metamor- phosis into chrysalides. For this labour the grubs 96 ROMANCE OF THE INSECT WORLD CHAP. are admirably adapted, while they are quite unsuited for browsing upon tender succulent * leaves. Their forcible jaws readily rend the dense woody tissue ; the legs are small, so as to prove no hindrance in the narrow tunnels ; and the head is protected by a hard FIG. 10. A Sack-bearing Caterpillar (Saccophora) ; from Bates. and reddish integument, affording solid support for the strong masticating apparatus. Larvae of moths of the family Hepialidse, abundant in Africa, America, and Australia, many of them of enormous size, have exactly similar habits. Our own country is not exempt from the ravages of the wood-borers of Ill HP:RMIT HOMES 97 Lepidoptera. One of the most injurious to many of our timber and fruit trees is the goat-moth caterpillar FIG. ii. Metura Sandersii from Australia; (a female). (Cossus ligniperdcL], so-called from an oily fluid that it exudes from its mouth of a very rank and pungent H 98 ROMANCE OF THE INSECT WORLD CHAP. goat-like odour. The caterpillars are hatched in crevices in the bark, and at first they feed in the bark, or between that and the wood. As soon as size and strength permit, they penetrate into the living tree, and make galleries and chambers, larger perhaps than those of any of our wood-boring enemies. Propor- tionately as the larva increases and its growth is amazing the diameter of its burrow becomes en- larged ; and since its course is erratic, and it remains in the larval condition for fully three years, the mis- chief it perpetrates is great. During the winter, how- ever, it lies dormant, and does not feed, in a cocoon ingeniously constructed from wood-chips roughly spun together with silk thread. This nest is often over two inches long and one in width. The larvae of the Scarabaeidse, the giants of their order (Coleoptera), are likewise notable wood-borers. Fortunately for us, for the amount of vegetable matter that they consume must be enormous, the larger species live exclusively in countries where a luxuriant vegetation can best afford their depreda- tions. At home perhaps no wood-boring beetle is better known than the little Scolytus destructor. It is destructive, particularly to elms, both in its mature and larva states, and many large trees, and even whole forests, succumb to its attacks. The mother enters the tree in search of food ; and to lay her eggs she squeezes herself in between the bark and the wood, where she bores out a cylindrical gallery, usually from three to five inches long, taking her about three weeks to complete. Along the sides the eggs are laid at regular distances apart, to the number occasionally in HERMIT HOMES 99 of a hundred and upwards. She then generally re- treats to the entrance and dies. As soon as the larvae are born they begin to feed. Urged by a wonderful instinct each arranges its body at right angles with the parent gallery, and proceeds to gnaw the wood steadily outwards. These side alleys become grad- ually larger to allow room for the growing tenants, but they all radiate from the central tunnel, and rarely interfere with each other by coalescence, their radiation more than keeping pace with their increasing size. Had the grubs all started parallel with each other the tunnels must have joined, and confusion and deprivation of sufficient food would have been the consequence. Full-fed, the larvae turn to pupae, and eventually pierce the bark and emerge. Large species of Calandra larvae, some two inches long, com- mit fearful devastation in the tropics, boring into the pith of large trees and into sugar-cane. South America suffers similarly from the immense beetle Titanus giganteus. In the West Indies, while the grubs of Lamia amputator and an allied species exca- vate mimosa and acacia trees, the perfect insects complete the mischief of their young by gnawing round the branches in a circular line, all except the central pith. Sooner or later the stems fall to the ground by their own weight or by the force of the wind. The parents' action, it is presumed, is directed to the prevention of a large flow of sap into and through the branch, which might harm the enclosed larvae and impede their metamorphoses. The leaves of garden trees and plants, the rose especially, are often traversed by white winding lines. H 2 ioo ROMANCE OF THE INSECT WORLD CHAP. Upon holding a leaf so marked to the light, the tracks are perceived to be due to the absence of the parenchyma ; they are in fact galleries or tunnels between the upper and lower membranes burrowed out by larvae, by the laborious procedure of eating the excavated material as they go. In most cases towards one end the gallery increases largely in width, and here the miner changes to pupa, and from this part flies when mature. The minuteness of these insects is realised when we consider that the thickness of many a leaf is not greater than that of this sheet of paper. Yet within this space the larvae find room to exist. It is worth while to remember that the early states of winged insects are always large in proportion to the imago condition, much of the substance being taken up by the rudimentary wings. Leaf miners belong to the orders Lepidoptera, Coleoptera, and Diptera, though Lepidoptera furnishes by far the greatest numbers. These are so minute that they can hardly be recognised as moths, and are simply exquisite gems of Nature. Amongst British Coleoptera, the common green tiger beetle (Cicindela campestris) is very interesting in its habits. Though small it is remarkable for fierceness, while for grace and beauty it challenges comparison with the grandest exotics. As a larva it has all the love for slaughter evinced by its parents, but its sedentary tastes and bodily structure, its white delicate skin and short legs, would seem to preclude gratification of the desire. So far as chase or open assault is concerned it makes no attempt ; it leaves warfare alone, and resorts to diplomacy. in HERMIT HOMES 101 With its short stout and spiny legs and powerful jaws it burrows out a vertical tunnel in the ground, and its flattened head ejects the earth detached. The tunnel is a foot long and of a diameter ade- quate to admit of the larva passing up and down ; towards the bottom it curves into a horizontal chamber. To make ready to catch its prey, the burrower ascends to the mouth of the opening, where it fixes itself steadily by pressing the back of its body against the walls, its eighth segment being developed into a hump-like projection which carries a pair of bent hooks. Its head and jaws lie perfectly level with the soil and are hardly visible, so that any insect will walk unsuspiciously over them. Instantly at the moment the larva feels the touch its sickle-like jaws are opened, it grasps the victim, and drags it to the bottom. Or the beetle upon becoming cognizant of the presence of the insect, slips with great precipitation down the burrow, and naturally the prey falls in after it and is soon eaten. An enormous variety of caterpillars, chiefly those of moths of the families Tineina and Tortricina, make homes of leaves, which they twist up and roll and fold and unite together to form safe habitations and abundant supplies of food. The genus Halias, which are very common to France, do infinite mischief to the vines. From the eggs, laid on the top of vine leaves in the middle of summer, the caterpillars are soon hatched, but they do not at once begin to feed, though surrounded by abundance and the weather is warm, they swing themselves by silken threads waiting to be tossed 102 ROMANCE OF THE INSECT WORLD CHAP. about by the wind. By-and-by the larva touches some prop or stem of the vine, when it penetrates into cracks in the wood, or beneath the bark, and hibernates until the late spring of the following year. Climbing up a stem, it now binds the young leaves and little bunches of grapes into a comfortable home, subsequently eating away the inside. Some cater- pillars confine their exertions to a single leaf. They fold it longitudinally and fasten the edges with silk ; or transversely, attaching the point to the middle nervure. Some roll it longitudinally others transversely, or part of it, to make a hollow cylinder. So minute are many of these insects that they cannot accomplish the feat by main force. Sup- pose the leaf is to be wrapped transversely. Again and again a series of silken cables are attached to its point and upper edges, their other ends are fastened to the centre. Each cable in succession is pulled and tightened by the larva's feet and spin- neret until the structure bends over, when it is securely held in position by fresh and shorter threads. In this manner the work is continued until the leaf is rolled into the tubular form desired, and the mechanic enters its home and feeds on the soft substance in almost perfect safety. In some cases the provision it obtains is ample; but should the life in larval state be long it may be compelled to construct other rolls, the nourishment from the first roll being exhausted. One species of leaf-mining caterpillars (Coleo- phora) as soon as they have tunnelled a cavity in the leaf, cut out the mined portion to form a case, in HERMIT HOMES 103 sewing the two sides together with silk. While the anterior orifice is circular, the posterior end is often diamond-shaped. Some Tinea, more saving of labour, make the tubes at the very edge of the leaf which acts in place of a seam. The owner does not repair or enlarge an old abode of the kind, but having eaten the best part of it, the larva abandons it and builds anew. Other species of Tineina make homes at our ex- pense out of bits of wool, hair, silk, or fur, from our dress and household stuffs, which they delight to gnaw. The tube of Tinea tapetzella is almost cylin- drical, and though rough exteriorly, is daintily lined with silk spun from the artificer's own mouth. When about to turn to pupa the larva closes one end of the house and suspends it bottom downwards. Before transformation it faces round inside the case, directing its head towards the end unattached. This larva forms only one home, which is altered from time to time as it becomes too small by additions of threads to either extremity. Should the width need enlargement, the occupant cleverly inserts new ma- terial into apertures made lengthways for the purpose. In colour the case always corresponds with that of the substance from which it is taken, and quite a motley appearance may be given it if stuffs of various hues are placed in the way of the little manufacturer. These dwellings are surpassed by the building per- formances of larvae of a genus of the family Psychidae, common to America, Australia, and Europe (sec Fig. n). Of all the species, the House Builder {Oiketicus Sandersii) is perhaps the most remarkable. 104 ROMANCE OF THE INSECT WORLD CHAP. The cases are made up of pieces of slender twigs, laid parallel to each other to form hollow cylinders, with care and exactness, much like the rods in old Roman fasces carried by lictors before the consuls ; hence the popular title of the makers is Lictor Moths. Frag- ments of wood and leaves, morsels of straw or grass or sprigs of moss, bound together by silk, are likewise employed. These homes the inmates carry about with them as snails do their shells, the head and thoracic segments alone protruding to permit them to grasp the leaves and twigs or whatever they are crawling over. The portion thrust forward is, however, hardly distinguishable, and it is very curious to see a tube moving along apparently of itself. As regards large Psychidae in America, the cases depend far beyond their bodies ; sometimes the total length is as great as from four to five inches. If the larva desire repose, it can retract its head and primary segments, and retire inside completely. To render itself quite safe when it is clinging to a branch, it can press the mouth of the tube against the branch so firmly that it is closed effectively ; if detached, the mouth can be drawn together by stout silken threads, arranged around its circumference. When about to become a pupa the insect withdraws within the nest, and closes it ; shut in, it prepares for its pupal sleep. The females of Oiketicus San- dersii, and of an allied genus, are wanting in wings, almost in legs and antennae in the perfect state, and environed in the tubes they pass the whole of their existence. None but an entomologist would take them for mature Lepidoptera. Ill HERMIT HOMES 105 Remarkable residences built under water by the larvae of Caddis Flies (Trichoptera) are wonder- FIG. 12. Part of the nest of a Trap-door Spicier {Nemesict eleanora) with single tube. fully like these homes of Psychidae. They are composed of fine stems of rushes and other io6 ROMANCE OF THE INSECT WORLD CHAP. plants, of bits of stick, leaves of grasses, minute pieces of bark and wood, fresh or decayed, of grains of sand, or gravel or mud, of hay, and any such debris that may have fallen into the water. Small fresh- water shells, yet occupied by their living inhabitants, are even affixed by the caddis to its case by their flat exterior, and the material or materials are glued together with a waterproof cement. The tubes tend to assume the cylindrical shape, and the interiors are lined with silk. Sometimes short lengths of plant stems are placed longitudinally side by side, with the utmost regularity, to form a perfect and shapely cylinder, perhaps four inches long. The morsels may be wound spiral fashion, or may be dis- posed into a many-sided structure, and so on in endless variety of arrangement. The larvae are each provided with two hooks on the soft skin of the end of the abdomen, so as to anchor itself firmly to its house. When about to undergo metamorphoses they fix their dwelling to something, and block up the ends, not with a solid stopping, with a kind of open fence, which, while it prevents the intrusion of enemies, allows free percolation of the water in and out. The adults may be observed any evening in summer flying about the banks of streams and marshes. The female enters the water to lay her eggs, which previous to this event she keeps for a short time in a green bundle attached to her body, her object being probably to expose them to the warmth of the sun before immersion. Enveloped in a glutinous mass they adhere to an aquatic plant, or to a stone. Upon an insect being hatched it im- in HERMIT HOMES 107 mediately forms its tube, for the protection of its soft delicate body and in view of its carnivorous disposition. When the transformations are almost complete, it eats its way through the end, and leaves its pupal skin by flight at the surface of the water. Larger kinds crawl up the stems of aquatic plants before abandoning the pupal envelope. A few caddis worms make immovable habitations, fixed to the spot whereon they were constructed. The grub is then compensated by larger range of movement ; its abdominal claspers are of much greater length proportionately, allowing it to extend itself to some distance from the entrance. Some moths (Hydrocampidae) are aquatic during their larval period. A common species in France fashion homes for themselves out of two pieces of leaf, sewn as it were together with a little silk, whence their heads and thoracic segments appear, as in the caddis. Among the habitations constructed by solitary architects, being perfect insects, for their own accom- modation, some of the simplest are those of the mole and field crickets. The odd-looking mole cricket (Gryllotalpa vulgaris) is one of the largest insects in England, stouter and stronger than any, and like its namesake it is fierce and irascible, and exceedingly voracious. In shape, and also in many of its habits, it is the very counterpart of the mole. Its appearance testifies to its mode of life. The body is almost cylindrical, the tibiae * of the fore-legs are short, broad, and flat, and as it were fingered, the feet being small, and almost hidden by the broad loS ROMANCE OF THE INSECT WORLD CHAP. palmated legs to prevent them being injured when the cricket is digging. Armed with its spade- like apparatus, it burrows out large excavations in the ground to a greater or less depth, vertical shafts with long horizontal galleries abutting. As a rule, it prefers loose and made soils, as in kitchen and nursery gardens and vineries. It cuts and eats through everything that comes in its way, so that its ramifications are a grievous source of mischief among young plants and flowers ; in fields they may be of certain use, the tunnels forming a kind of sub-soil drainage. Like the mole, it reserves a distinct chamber apart from its other galleries for its young. Formed at no great distance below the surface, this room is about three inches in diameter, and nearly one inch high, very neatly made, and its walls are carefully levelled and hardened to resist the action of the rain. Here the eggs are laid secure from all ordinary foes, and no doubt their hatching is effected by the sun's warmth, which will penetrate to the slight depth at which they lie. Secluded in its home, the insect passes its life in a state of absolute solitude, issuing forth at nightfall, when alone it dis- ports itself on its wings. It never soars to any great height. In character and habits Ac/ieta campestris is very similar. At night it comes out and sits just within the entrance to its hole, chirping away at its monotonous song for hours together. Being wary and timid, it takes alarm at the least noise, and retreats inside with precipitation. But it is combative, and may be drawn out by inserting in HERMIT HOMES 109 down the tunnel a stick or straw, which it clutches as in a vice. In France children fasten a fly, or ant, to the thread, or stick, that they poke down the nest, but this is quite a superfluous addition, for it is anger and not hunger that incites the cricket to grasp the intruding object. The largest known species (A. monstrosa) are natives of India, and make burrows sometimes three feet deep. No solitary insects surpass spiders in house-build- ing. Many of their homes are not merely intended for the rearing of their young, but are homes in the true sense of the word, where they reside day after day, and to which apparently they become fondly attached. They consist chiefly of burrows in the ground. Even in England we may come across little specimens tunnelled out in some sandy soil, and lined with silky membranous tubes to prevent the earth from falling in. From the mouth a web is spread to catch the prey, while the hunter lies concealed at the bottom, waiting for the approach and capture of victims in the snare above. The finest simple spider tunnels belong to the Mygalides, a family of the tropics that comprise the gigantic creatures of their tribe. Several species of the genus Mygale have great hairy bodies, almost as large as sparrows, and an expanse of limb no less than half a foot and more. One very robust fellow, Mygale blondii by name, a great burrower, forms a broad slanting tunnel some two feet deep, and the sides are lined with a silken coating. This spider is nocturnal, and may be seen at sunset occasionally at the mouth of its den, keeping watch for passing no ROMANCE OF THE INSECT WORLD CHAP. delicacies, which being caught are destroyed at leisure in the safe retreat. Probably it seldom wanders far from home. The greatest perfection of tubular nests, however, culminates with the so-called trap-door spiders. For beauty of workmanship, for ingenuity in arrangement, for marvellous cleverness in overcoming difficulty and avoiding danger, these arachnids * must be assigned a front place among Nature's handicraftsmen. They inhabit many warm countries, notably the West Indies, the United States of America, India, and Australia. The typical nest is a cylindrical tunnel in the ground, beautifully lined with silken web and protected by a valve or lid " the door " fitted accurately into the frame of the orifice at the surface, and like our doors possessed of a hinge, upon which it turns with the greatest freedom, allowing it to be opened and closed at pleasure. Some of the larger kinds of these nests ; as in the West Indies, are a foot deep and about an inch in diameter, and are dug out by the strong jaws of the spiders often in a steep bank of bare clay. The silken lining tube may be removed from the burrow, and is then seen to be double ; the outer covering being comparatively strong, harsh, and thick, and deeply stained of the colour of the earth, while the texture of the inner layers is very different, being nearly white and soft, and smooth, the smoothness, however, not precluding certain irregularities of surface, it resembles rough and unsized paper. The door is composed of the same substance, and is continuous with the tube for about a third of its circumference forming the hinge Ill HERMIT HOMES in or sufficiently to ensure that it does not fall care- lessly to either side, but comes with precision into the mouth and closes it. Perfect closure is rendered a FIG. 13. Part of the nest of Nemesia meridionals, showing the surface door open, and the lower door pushed across so as to close the principal tube. The subsidiary tube ends in a cnl-de-sac. matter of certainty by the aperture of the tube be- ing slightly recurved to form a brim or lip, and the interior surface of the lid is a little convex. 112 ROMANCE OF THE INSECT WORLD CHAP. Exteriorly it is level with the ground, and the silk is coated with earthy particles. In fact, all trace of the work is completely obliterated. Travellers to the West Indies describe the alarm they at first experi- enced in seeing the earth open, a little lid lifted, and a formidable-looking spider peep out of the hole. These tunnels are seldom situated in flat ground, where the door would lie horizontally when closed. A sloping or nearly vertical bank is usually chosen, and the hinge is placed at the highest side of the opening, so that the door when pushed up on the entrance or exit of the owner falls to by its own weight, ensuring concealment of the nest. The edges of the door are accurately adjusted to the bevelled lip of the tube, and offer a certain degree of mechanical resistance to the entry of an enemy. Should the spider be at home when his door is touched, he is made aware of the impending danger by the vibrations of the silken threads. Speeding to the scene of action, he hooks his hind legs to the lining of the lid, his fore-legs to the side of the tunnel, and turning upon his back resists the threatened invasion with all his might. Excessively bold and courageous, he defends his territory with the greatest pertinacity; nothing short of actual violence will in- duce him to desert it. In some nests a row of minute holes, as though pricked with a fine needle, is pierced round the free edge of the lid, another row lies immediately within the margin of the tube. It has been suggested that these help the spider in holding the cover against attack ; in Mr. Gosse's opinion they serve to admit light and air to the dwelling, and are in HERMIT HOMES 113 indispensable, owing to the density of the lining material and the tightly-fitting lid. The row round the edge of the tube may be, as it were, a stock in reserve in case of accident, should the lid holes happen to become effaced with particles of the sur- rounding earth. Some trap-door nests. of the south of Europe (see Figs. 12 and 13) have thinner doors, less tough and coarse in texture, and frequently they are not wedged into the top of the tube like a stopper, they simply rest over it. Often the excavation is amidst moss and other low undergrowth, securing safety in obscurity of site. The lower extremity may end in a short spur-shaped enlargement. Sometimes a subsidiary branch is dug obliquely upwards from the middle to the surface, where it is lightly closed by a few silk threads ; usually this shoot is a mere cul-de-sac (see Fig. 13). A hanging-door exists at the junction of the two tubes ; and at the depth of two or three inches down the main one a door of the same kind may be found. If an enemy, a parasitic fly, for example, force its way into the nest by the principal, or the sole en- trance, as the case may be, the spider is believed to press up the last-mentioned door, leaving the intruder to all appearances to an empty domicile. Should this manoeuvre fail, and the hunter be not deceived by the trick, the spider can dodge into the branch, and draw the second door to behind him. Where the branch extends to the surface, if needs be, he can evacuate his premises and escape. Certain spiders" (Lycosides) raise a cylindrical hollow tower over their burrow, much like an ordin- I ROMANCE OF THE INSECT WORLD CHAP. ary bird's nest on a diminutive scale, forming it very symmetrically of bits of grass, leaves, sticks, and rootlets, or of clay, little stones, and a few stronger sticks, loosely interwoven with silky secretion (see Fig. 14). Evidently it plays the same part as a trap-door, and contributes to the concealment of the hole. On removing it the shaft is found to be often twelve and fifteen inches long ; in one instance a depth of twenty-two to twenty-three inches was reached. It is perfectly round and perpendicular, and may widen out into two enlarged cham- bers, an upper and a lower one, but the tunnels of many ground-spiders are of the same dia- meter throughout. Both the nest and the tube may be silk-lined, or the latter may be innocent of web ; usually the entrance is neatly underwoven with this substance mixed with sand. Mrs. Treat, an eminent American naturalist, describes another species of spider as establishing a dome-like roof over its tunnel, made up of a canopy of web overlaid with leaves, blades of grass, and such like matters, the whole being securely fastened down except at a place. of entrance and exit, which is only discovered with the closest scrutiny. These spiders have the habit of closing this FIG. 14. Nest of the Turret Spider (Lycosa areni- cola\ United States, America. in HERMIT HOMES 115 opening in the autumn season for the space of two or three weeks, in order to elude the raids of the fossorial wasps, who are then engaged in provision- ing their young. The wasps run over the ground, peering into every nook and cranny, and should one alight upon a nest unbarricaded, down it goes and returns with the inmate, rendered powerless by its poisonous sting. During the winter the doors are likewise hermetically sealed. Unlike most of its kind the spider Argyronetra aquatica is aquatic, or rather amphibious, and habit- ually spends the greater portion of its time in the watery element, constructing its home, and surround- ing itself with the atmospheric air essential for respir- ation. It may be found in various parts of England Cambridge is a favourite locality in rivers and pools and ditches where the water is calm and un- troubled. Its cell is composed of silk, and is more or less oval in shape and about half the size of a pigeon's egg, and is suspended in a vertical position, the open part being directed downwards. The spider commences by spinning loose threads of silk in different directions, attaching them to the leaves of water-plants the framework of her building so to speak. Within these supports she sets her beautiful transparent chamber. Before occupation it is necessary that it be filled with air. Slowly but surely ascending to the surface, assisted by a thread fixed to the leaf or other house prop below, and to the outside of the water, she obtains a bubble from the atmosphere, and imme- diately and quickly descends with it by the same route to the bell-shaped nest. Having arrived I 2 u6 ROMANCE OF THE INSECT WORLD CHAP. there, she disengages the air. These journeyings are repeated perhaps fourteen times, and at last her apartment becomes full of air to the exclusion of water, the globules of air having replaced the water. Into the dome she enters, and settles to rest, undis- turbed by the agitations above, head lowermost, after the manner of her tribe. The air acquired is mechanically entangled in the tissue covering the animal's body, and is held on by the two hinder legs, which are crossed over the abdomen at the instant that the bubble is seized. To this home the spider brings her prey, and in it lays her eggs, spinning a white silken saucer-shaped cocoon for them, and placing it against the inner side of the cell and near the top. The young remain beneath with their mother until they are grown a little, and have become strong enough to form sub-aquatic dwellings on their own account. The so-called raft spider (Dolomedes fimbriatus] is amongst the largest of the British species, and the globular cocoon, which the female carries about with her, may contain as many as several hundreds of eggs. The spider not only lies in wait for its prey, but chases them like a carnivorous verte- brate.* It pursues them on land, and in the water, on the surface of which it runs fearlessly. When thus employed it gathers a quantity of dry leaves and rubbish, and unites the collection together with threads of silk into a resting-place or raft. On this the maker sits, and is blown about by the winds and currents. It knows no lack. Aquatic insects are constantly coming up to the outer air to in HERMIT HOMES 117 breathe, insects just completing their transformations are acquiring their wings at the surface, and many smaller and less powerful than our hunter are abroad on the water on the same errand, to gain their liveli- hood. Any and all of these make capital food for fimbriatus, who pounces upon them, and devours them on the raft. Should it see an enviable morsel at a distance it darts off the platform, returning to enjoy its meal. On the approach of an enemy it can pene- trate the water, and can exist submerged for some time. Lycosa piratica, a closely allied species, also chases its prey on the water, but it makes no raft. It like- wise is able to descend below the surface, when it breathes by means of air confined among the hairs with which it is clothed. CHAPTER IV. SOCIAL HOMES. Diversity of method of insect architecture, its beauty and size The word architecture as applied to this portion of insect economy Societies of social caterpillars Three types of nests of ants Home of Common Wood Ant external conformation internal plan doors formation and regula- tion of society A solitary " queen " as founder of a colony Singularity of wood-ant in preference for open-air life Mason Ants Extraordinary dimensions of homes of Saiiba or Coushie Ants Their leaf-cutting propensities Mushroom-growers Mason Ants of New World ; their disks, roads, refuse-heaps, store-rooms, nurseries, lum- ber closets, position as farmers, &c. F. fuliginosa and other carpenters Standing-army of Bull's Horn Acacia Ants as guardians of other plants Remarkable pensile nests of Crematogaster, Myrmica Kirbit^ (Ecophylla smaragdtna, &c. IN no branch of insect work are more admirable means employed to bring about the desired ends, or is greater diversity of method found, than in that of insect architecture. The beauty of the buildings in many cases is incomparable, and generally speaking the abodes attain a magnitude colossal as compared with that of their creators. It may be CHAP, iv SOCIAL HOMES 119 exception will be taken to the use of the word archi- tecture to designate this portion of the insect economy, and perhaps the term can hardly be applied in fairness to homes which are mere tunnels and galleries bored in the earth or in wood. But who would deny it to the exquisite pensile nests of the English wasps, or those of many a foreign relative, to the geometric precision exhibited within the hive of the honey-bee, or to the edifices of some ants, as will be presently discovered. Among the communities which combine their operations, there are those of which the object is simply the protection of the individuals com- posing them. To these societies belong the cater- pillars of certain species of moths. The homes formed by these larvae, though they are not elaborate, are interesting in several minute circumstances. But they fall short in every respect of the attractive nests fabricated by companies of insects in their perfect state, in view not only of self-preservation, but of the nurture and education of their young as well. Of these the nests of different kinds of ants are the most simple in their character. None the less on this account they are worthy of investigation, owing to dissimilarity of design both in outward form and internal plan, on account of the materials composing them, and the manner that they answer the wants of the species. Their size is astonishing, and outrivalled only in the inferior departments of the animal kingdom by the works of the coral animalcula. They may be formed with earth, and consist either of excavation underground, or of excavation combined with building 120 ROMANCE OF THE INSECT WORLD CHAP. on the surface. Their makers may be called masons. Ants are likewise carpenters by trade, hewing their homes out of solid tree trunks and roots often with an excessively involved and delicate art. A third kind of nest is pensile, and composed of leaves, or of collections of vegetable or animal matters. These three general types include many most interesting modifications, each species of workmen being endowed with the operative talent that suits them best. The common Wood Ant, otherwise named the Hill, or the Horse, or the Red (Formica mfa*\ is a good representative of the group (Formicites*) to which appertain the true ants. Few people in this country, and throughout all central Europe, are unacquainted with the dwellings (see Fig. 15). They consist exteriorly of elevated hillocks or mounds, many of them of large dimensions, made up of bits of straw, wood, little stones, morsels of earth, leaves, grain, in a word, of anything portable and within reach. Usually they are situated in woods or their neighbourhood where the undergrowth is not too dense, often under some shelter such as a bush or tree. They are especially plentiful in fir-woods, where the fallen needle-like leaves of the firs afford abundance of building material ready to hand. At the first glance the dome seems nothing but a rude confused mass ; in reality its internal con- struction presents an arrangement that is excellently adapted to promote the welfare and comfort of the inhabitants, ensuring them free liberty of action throughout, and protection at once from extremes of heat and cold by the maintenance of a genial warmth. It is composed of numberless small chambers, united tv SOCIAL HOMES 121 together by galleries, in order a series of flats or storeys ; besides these there are more or less irregular avenues communicating with the outside. In fact, FIG. 15. Section through a typical nest of Formica; after Smith. the fragments, instead of being thrown down confusedly and without purpose, are carefully disposed after a defi- nite though not very regular plan. The beams are piled 122 ROMANCE OF THE INSECT WORLD CHAP. ingeniously, and their interstices in some parts of the nest are filled up with earth, grains, and scraps of dried leaf, giving strength and solidity to the whole mount. It is worthy of note that the longest sticks are reserved for the galleries, in order to prevent by every possible means the materials from falling in, and causing in- terruption in the routes of communication. Due to this orderly method of erection the domes can with- stand the shocks both of rain and wind, without being penetrated by the one or blown away by the other The nest is completed by a corresponding labyrinth of chambers and galleries in the ground, from which mining system the earth granules utilized in the upper fabric are obtained. To all appearances the entrances to the galleries from the outside are exceedingly ill-fitted for the ex- clusion of damp and of nocturnal intruders on the ants' privacy. The openings exist at the owners' pleasure. In the early morning they are nowhere visible, and the nest is as though deserted ; or a few small cracks are apparent, whence issue forth some workers betimes. By-and-by, as the day advances the passages are swept and cleared, and the holes are made for the day, while the entire population become actively engaged in their several avocations. Only if the day be fine however. Should it rain the portals are kept fast, or if the sky be cloudy they are partially opened. The drawing in of night sees them wholly closed, when all the inmates gradually retire to the interior to enjoy rest from labour, confident of peace, a few sentinels being left to guard the gates. Should a brilliant morning and consequent wide-flung doors IV SOCIAL HOMES 123 be succeeded by heavy showers, the ants hasten to prevent catastrophe by the re-establishment of the barriers, and every member appears willingly to give its quota of help to speedily accomplish the work in hand. The formation of a nest may be traced from the beginning by brief close investigation into the state of society of a large community during the early months of summer. Here, in addition to the presence of the vast multitude of wingless worker ants, and some females now in like condition, a certain number of young winged males and females are all ready and eager to escape from home. Soon after their birth, taking advantage of a favourable opportunity, usually on some warm still afternoon, they adventure out. Some of the females, or so-called ' queens,' are com- pelled to return, and having torn off their wings which are no longer of use, with the assistance of the workers, they settle down to an unintermitting seden- tary existence, replenishing the population of the only abode they will ever know. Other females while in this comparatively helpless condition are conveyed by workers to new situations, where they become the founders of new colonies. In effecting the establishment of a colony, the little company at first betake themselves to mining. With their mandibles they set arduously to work, until by dint of prolonged and strenuous labour a cavity in the earth is formed. Meanwhile some of the future inhabitants of the nest may be seen wandering about the vicinity in search of building-stuffs for the exterior. Scrap after scrap is gathered, and laid over 124 ROMANCE OF THE INSECT WORLD CHAP. the entrance to the hole, one piece being crossed over the other, while the lowermost bits are stuck into the earth so as to fix the foundations of the aerial erection. Many of the little creatures are equally busy in ming- ling the vegetable morsels constantly brought in by their fellows, with the grains of earth thrown up in hollowing the underground apartments, tempering the granules with rain water, which harden in the sun and effectually bind together the different substances. Thus do these fragile materials, without cement and not even interwoven, constitute a tolerably firm com- position, one able to withstand the weather, and the bustling energy of the ants in their life's occupations. Day by day the stories composed of chambers, cells, large and small, and passages, are superimposed upon one another, and the edifice increases in size, cavities being left open throughout the day as the work proceeds, where the builders intend to construct the galleries which are to lead to the interior. During the first fine days of the year the eggs begin to be laid, and from this moment until as perfect insects they are fully competent to ' do ' for themselves, the young become the objects of tenderest solicitude to the nursing ants. Placed alternately in the recesses and the outer chambers of the nest, in the first at night for warmth, whence in the morning they are removed to the upper rooms where the sun's heat penetrates, so as to be maintained at a uniform temper- ature, gradually under this fostering care the eggs increase in bulk, and the larvae are hatched. Now even more than formerly, the little ones demand attention. In addition to change of room every morning and IN- SOCIAL HOMES night, and frequently at shorter intervals, in conse- quence of sudden alteration in weather, as an unlocked for shower, which will cause the workers to hurry their charges away from the surface to the inner depths, or should the sun become too hot in the day cells, the rapidly developing nurslings have to be vigilantly cleansed and fed, When full grown the majority of ant-larvae spin silken cocoons around them. In this state they are well known, and collected as food for young pheasants. Popularly they are termed ants' FIG. 16. Section through the nest of the Leaf-cutting Ant CEcodoina ccphalotcs from Belt. eggs, but how the egg could exceed the size of the insect that laid it is a problem that never seems to suggest itself to the nomenclators. The pupae, like the larvae before them, are carried by the workers from room to room, and for the same purpose. Eventually their metamorphoses are almost complete, still the nurses do not dare to relax their attendance upon them. Without assistance the immature ant is incapable of freeing itself from its covering, and would perish miserably, ere it can be said to have really lived. The workers, observant of the right moment, tear open the 126 ROMANCE OF THE INSECT WORLD. CHAP. cocoon with their mandibles, and set free the now perfect creature. For a little while it is weakly, and unable to take care of itself, and assume its share of the tasks of the hive. So long as feebleness continues the nurses never lose sight of their tender dependant, they watch it until strength and knowledge of its duties are acquired. The affectionate workers even accompany their young winged nurslings to the surface of the dome, and feed them for the last time before they start, in turn, on their nuptial flight. On the occasion of this swarming, which has been already alluded to, it was formerly thought that when any female alighted at a great distance from the nest, driven thither by the wind, or carried merely by flight, she found her way back to her original quarters. This has been proved to be impossible. On the con- trary, a solitary female falling to the ground in an out- of-the-way spot, has been observed to creep into a hole, and to cast aside her wings, and with them her dignity, as it were, and usual exemption from toil, taking upon herself unaccustomed menial offices. Alone, unaided, she constructs a small nest, and lays some eggs, and feeds the young, and rears them to maturity. Wonderful to say, she appears to be aware of the necessity of developing them into workers. No sooner do they attain perfection and the capacity to assume adult labour, than the mother relinquishes the duties foreign to her nature, and falls back on the sole occupation of egg-laying ; leaving her progeny to enlarge the dimensions of the dwelling, to keep it in repair, to defend it, to provision themselves and her with food, and to act the part of nurses to the young, SOCIAL HOMES 127 with which she continues to stock the colony. Subse- quently these include among them winged males and females. The wood ant is singular in having preference for an open-air life during the heat of the day, and is con- tinually on the outside, seeking for food or employed on the exterior of the dome until darkness compels it to desist. It is seemingly fearless of being surprised by enemies, at least during the FIG. 17. Saiiba or Leaf-cutting Ant carrying leaf ; from Bates. day, and does not construct a long covert way to its nest, as if for concealment, like the yellow and brown kinds. But the wood ant never fails in its precaution against attack and assault of the dwelling by night, and when business must be completed after dusk, it is done with shut doors. The actual manner of obliterat- ing the apertures is noteworthy. To the entrance of the avenue which the ants desire to close, beams are brought forward and deposited in the stubble ; similar 128 ROMANCE OF THE INSECT WORLD CHAP. morsels arc placed above but in another direction, and pieces smaller as the work proceeds. At length bits of dried leaves and other materials of larger size are laid down ; the exact art in miniature of car- penters when roofing a house. Nature seems every- where in advance of those inventions of which we as men are so proud. Doubtless had careful observers of these things existed in early times, many mechanical devices which have taken civilised nations centuries to discover and to perfect, would have played their part in the world's history considerably sooner than they have done in fact. The nests of F. rufa are particularly large in the fir- woods of Scotland, where I have seen them the size of small haycocks, and occupied by absolutely countless numbers. Yet these are mere molehills as compared with the enormous mounds of species, ap- parently of the same family, in warmer climates. Stedman speaks of ant-hills in Surinam over six feet high and at least a hundred feet in circumference ; Malouet mentions having come across specimens in the forests of Guiana of a height that he computes at fifteen or twenty feet, with a diameter at the base of from thirty to forty. Although the architecture of most ants is possessed of strong points of resemblance, each species chooses a particular position for its nest and establishes it on its own plan. Like F. rufa, many that work in earth are admirable subterranean burrowers. Perhaps the brown, F. brunnea, carries off the palm, a species not very common in this country. Though one of the smallest, it is remarkable for ingenuity and the beauty iv SOCIAL HOMES 129 of its finished workmanship. The nest consists of series of stories, sometimes not fewer than forty, twenty below the level of the soil and as many above, which last are not horizontal, they follow the slope of the ant-hill, and lie one upon the other to the ground floor, presenting the appearance exteriorly of an elevated dome-shaped mound. Each story, separately considered, is composed of cavities, narrow chambers, and long galleries which preserve communication between both. All are smoothed as though with a plasterer's trowel, and are about the fifth of an inch high. While some of the more spacious rooms have only one entrance from above, or in addition a second leading to the story lower, some are large open spaces, being in fact the points where meet several of the main galleries, a kind of cross roads, and are connect- ed with subterranean passages frequently carried to a distance of several feet from the hill. The arched roofs of the chambers, which are often more than two inches across, are supported by excessively slen- der partition walls, or by small pillars and true but- tresses. The building material consists of soft clay excavated from the bottom in mining, and is often moist enough, since the sun cannot penetrate to the lower depths. Were the supply taken from the surface, business would be practically at a standstill during dry weather. To enable him to watch these ants, Huber had a carefully arranged contrivance constructed, a sort of vivarium, where the insects were furnished with the conveniences to prosecute their ordinary work. While some might have been seen busily engaged upon the K 130 ROMANCE OF THE INSECT WORLD CHAP. soil, kneading and moulding it with their mandibles into ductile pellets, an action analogous to brick- making, others were as diligently scooping out shallow cavities in the clay floor, the ridges that were left being the foundations of the future walls. On these pellet after pellet prepared for use were adjusted, and spread firmly and evenly, greater compactness being obtained by light pressure of the ants' fore-feet. However numerous the masses may be, the walls when finished look uniform and unbroken. Openings are made where necessary in the masonry to admit of communication, and when the two walls of any gallery or chamber reach the proper height the space between them is covered in by the ceiling. The method of construction is to mould pellets into each angle of the apartment, and also to the top of the pillars, extending the roof by successive layers of pellets, as fast as one row becomes dry a second being added until the approaching sides meet. No glutinous matter is introduced into the masses of clay by way of mortar or size for consolidating or strengthening the building. The particles adhere merely by juxtaposition, the peculiar kneading and biting to which they are subjected rendering them very tenacious. Moisture, however, is absolutely necessary to the ants, and if deprived of it in the shape of gentle showers, or if the clay from below is not properly damp of itself, they abandon their labour as hopeless and wait patiently for rain. In the event of the con- tinuance of dry weather, they pull down again the crumbling apartments that are not covered in. As regards the ants kept by Huber in captivity, he found IV SOCIAL HOMES that whenever they ceased to build he could almost always induce them to resume by dipping a brush in water, and striking it with the hand, so that the fluid fell like fine rain. As soon as they felt the refreshing drops they would immediately regain their activity. Much wet is as inconvenient to them as a drought. But when their walls are complete they are very strong, and extremes of heat and moisture appear only to increase the cohesion. These insects FIG. 18. Agricultural Ant of Texas (Pogonoinyrmcx barbatiis). Large flat circular disk and open roads made above the subterranean formicary; from McCook. avoid the sun, and seem to work chiefly at night and during light misty rain. Wonderfully assiduous, they have been known to construct a story, with all its saloons, vaulted roofs, partitions, and galleries, in from seven to eight hours. Two other masons common over a great part of Europe, the ash-coloured or dusky F. fusca * and the so-called mining ant, F. cunicularia, form similar nests, but the last-mentioned makes no dome. Both K 2 132 ROMANCE OF THE INSECT WORLD CHAP. are probably less particular in the selection of their building materials than F. brunnea. The hillock of the ash-coloured ant always presents thick walls, the stories are well marked, the chambers large with vaulted ceilings, and the galleries strictly speaking are large oval passages. The chambers and galleries rest upon a solid basis, arising from the mode of heightening the habitation. The existing roof is covered with a thick layer of fresh moist clay, converting it into a floor for the pro- posed story. On this the builders proceed to plan the erection intended, forming FIG. 19. Agricultural Ants cutting . . r , , . down obtruding grass; from CaVltlCS OI almOSt CQUal depth McCook. . . in it, and raising the inter- vening elevations into wall-like partitions, having first reduced the foundations to a due thick- ness and removed the loose earth from the floors of the apartments. Lastly, all is closed in. The muscular power and energy of these ants are truly amazing, as exemplified by the observations of Huber, who watched a single worker make and roof in a gallery two to three inches long, she herself fetching, and kneading, and placing her own materials, and the interior was rendered perfectly concave, a day's work, in propor- tion to her size, far beyond the power of man. iv SOCIAL HOMES 133 This ant prefers a nest-site with southern aspect. The Saiiba or Coushie ant (CEcodoma cepJialotes), peculiar to tropical America, is a mason that exceeds the European species in the magnitude of its labours. Its nests, found in plantations and woods, consist of dome-like edifices elevated over underground earth- works (see Fig. 16). The domes differ in colour from that of the surrounding superficial soil, owing to being formed of earth brought up from a considerable depth. Frequently no less than forty feet in diameter, with a FIG. 20. Gravel cone nest of Honey Ant built partly round a tuft of gramma grass ; from McCook. height of two feet, measurements simply gigantic having regard to the builders, they dwarf into utter insignificance the mightiest efforts of man, the relative dimensions of the workers being considered. But though the domes are immense, they arc as nothing compared with the limits of the underground galleries, which are often of almost incredible extent, and show no trace of their presence, and suddenly the ants will come to the surface where least expected. So vast are the subterranean passages and so complicated, 134 ROMANCE OF THE INSECT WORLD CHAP. that they have never been thoroughly investigated, but an idea of their size is obtained from the fact that once when sulphur smoke was introduced into a nest it issued at an outlet seventy yards distant. Mr. Bates relates that a species has been known to excavate a tunnel under the bed of the river Parahyba, in Brazil, at a place where it was as broad as the Thames at London Bridge. Galleries radiate from the dome in all directions ; the nest also contains rounded chambers about as large as a man's head. The entrances are small and numerous and generally closed ; very rarely the ants are seen at work upon the mounds. Popularly known as leaf-cutters, these ants arc a veritable scourge in central and tropical America, where they abound, and may constantly be observed forming broad processionary columns on their way to and from the scenes of the fearful havoc they commit, persistently and laboriously abstracting quantities of pieces of foliage from the trees as large as sixpenny bits. Valuable cultivated plants suffer most from their attacks, the orange, lemon, coffee, and mango espe- cially. In some districts agriculture has been rendered almost impossible in consequence, or has been abandoned. Their mode of cutting off the bits of leaves is very interesting. Equally attractive are the insects when in order of procession, returning home laden with their spoil like multitudes of animated leaves, each workman marching along holding its portion in its jaws erect by one of the edges. The habit has obtained for them the name of Parasol Ants, the burden being supposed to be carried to shield its bearer from the sun (see Fig. 17). It is now ascertained iv SOCIAL HOMES 135 that the gleanings are minutely subdivided and stored in the formic chambers until decayed. On the rotten mass grows a minute white fungus on which the ants feed ; they are in fact mushroom growers and eaters. Great interest is attached to certain mason ants of the New World, the so-called Agricultural Ants of Texas and Florida and the Occident Ants of the American plains. The formicaries of Pogonomyrmex barbatus are scattered over the light FIG. 21. View of the nest of a Provident Ant (Atta barbara) from Mentone showing a granary excavated in rock and the conical refuse heap. soil on the hill slopes of Texas, in the deep dark earth of the highlands and valleys, among the rocks, indeed almost everywhere. Externally they are for the most part flat, smooth, circular disks in the midst of sur- rounding herbage, presenting the appearance of minia- ture " clearings " in the American backwoods (see Fig. 1 8).. Some of them are as large as from seven to twelve feet in diameter, the average ones reach a diameter of only four or five feet, covering a space of from twenty- 136 ROMANCE OF THE INSECT WORLD CHAP. one to thirty-six square feet. From this central plat- form, as it were, broad and similarly clean paths or avenues branch off into the encircling vegeta- tion, they gradually narrow, and almost imperceptibly blend with the vacant spots between tufts of grass. In number these paths are usually three or four, sometimes there are as many as seven, with a width at their entrance upon the disk frequently of two and a half to three inches, occasionally enlarging to five or six. A hole within the disk leads to the sub- terranean regions, which include store-rooms for the seed, nurseries, and other chambers, their arrangement being more or less in stories. Extraordinary must be the labour on the part of these insects in effecting the removal of the rank vegetation of the country from the bounds and approaches of their nest. The weeds stand in a well- nigh perfect circle around the circumference of the cleared space. Tufts of grass, wild sage, the daisy, and such-like sturdy growths are there, with stalks at times as thick as one's thumb, and over two feet high. The plucky beings appear to bite, and saw, and twist, and tug at the leaves and stems until they are severed and can be borne away (see Fig. 19). Pre- sumably, the avenues are denuded in similar fashion. During the winter months, when many of these ants retire under ground, the clearings fall into sad disrepair, and the weeds intrude, to be as vigorously expelled in the following spring, when warmth once more recalls the workers to set all things in order. The use of the pavements is doubtless to facilitate entrance to, and exit from, the home, so as to reduce the iv SOCIAL HOMES 137 fatigue inseparable from toil. The avenues are made with like intent, enabling speedy and ready journey- ing to the harvest grounds and back. The exertion involved in searching for the wished-for plant-seeds, in adjusting them for convenient carriage, and in bearing the weights, is remarkable considering the size of the workmen at their calling, and amply justifies them in lightening their labours by every means in their power. The seeds are stored in large quantities, entire as gathered, and also stripped of their shells, and are believed to serve the gleaners as food during their confinement in winter. Ref- use heaps, consisting of the discarded shells and glumes,* are raised outside, and have been facetious- ly termed the kitchen middens. On opening some of the nests in spring the granaries are discovered to be not nearly so well stocked as in the fall, a fact that argues strongly in favour of the actual consumption of the seed. As the season advances, and autumn once more deepens into winter, while some disks continue to be kept free of herbage of every description, many of the platforms become partially covered with a row of one particular plant, the Aristida stricta, or "Ant Rice." The circular cluster is strictly limited by the outer bound or circumference of the clearing, beyond which grows the ordinary wild grass of the locality. It ripens by the ensuing spring, and there seems little doubt that from it the ants then gather in a harvest of seed, subsequently cutting down and removing its dry stubble, along with any weeds that have trespassed on the private property during winter; leaving the 138 ROMANCE OF THE INSECT WORLD CHAP. " pavement " again unencumbered until autumn, when the same favoured plant once more presents itself. It has been urged that the needle grass is deliberately sown by the ants on the cleared ground in summer, and is cultivated with the intention of reaping a crop from it in the following spring. It seems hardly possible to credit them with such wisdom. Nor on the other hand, as the opponents of this theory believe, is it likely that they are overtaken by the autumn " rice," and are unable to prevent it, since surely the power which enabled them to eradicate all usurping winter growth from their domain in spring, would admit of them keeping it clear. Besides, the exclusive occupation of the disk by this grass, so long as the ants are up and about, counts in favour of voluntary action on the part of the insects. Probably the Aristida is seeded yearly in a natural way by drop- pings from the plant, or from seeds dropped or cast forth by the ants ; and the ants find it to their ad- vantage to permit and foster the ensuing growth, because of greater convenience of harvesting the seed, while, farmer-like, they expel all other vegetation from their precincts. In some instances the central clear space is occupied by a low mound, in shape some- what like a volcanic cone with a crater-like depression- at the summit. A distinct flat bare belt or zone may exist between the mound and the margin of the nest, of no great width ; or the grass of the surrounding prairie may grow up to the cone's base. The material composing the mounds is a light sandy soil. Other nests have gravel disks. Round IV SOCIAL HOMES 139 the opening to the underground apartments is a mass of gravel, which may accumulate into a little heap, and beyond extends the smoothed belt of ground with circulatory margin. Entrance to the interior is by FIG. 22. Fragment taken from the trunk of an oak inhabited by Fuliginous Ants ; from Huber. one, two, or more gates ; apparently the tendency is to increased numbers in nests with cones and mounds. Immediately within the gate is a vestibule, smooth, and from one to two inches wide, which, at a distance from the entrance of from half an inch to HO ROMANCE OF THE INSECT WORLD CHAP. two and a half inches, diverges into tubular galleries connected with the granaries and nurseries. In general these rooms are circular, oval, and crescent- shaped. The depth to which they are carried prob- ably varies, but nests have been excavated as far as four feet below the surface and no termination of the mining was reached. Rooms even at two and a half feet down are packed with seed, and narrow gang- ways are left at the outer margin between the grain- heaps and the wall. The elevations upon the disks are used for habitation, and are not simple accumulations of earth excavated from the underground cells and galleries. The architecture of the Florida harvester (P. crndelis] is in close resemblance to the cone structures of the Texan agriculturist. The nests of the other known North American congener of Pogonomyrmex, the Occident Ant of the great American plains (P. occidentalis\ are similar in exterior to the gravel-covered cones of the Texas and Florida harvesters. They form conspicuous objects upon the level plains, or gently sloping hills, alike by their elevation and their great numbers. The cone rises to a height rarely exceeding ten inches, though it appears much more, owing partly to the situation. It generally stands in or near the centre of a round or elliptical pavement or clearing, but no crop of " rice " breaks its monotony ; it is always totally freed of vegetation, unless it be for an occasional tuft or blade of grass straggling here and there. Its use then differs from that to which the Texan nest-space is put, since it is no harvest-field. Its advantages, however, are manifest. By it the ants gain easy IV SOCIAL HOMES 141 ingress and egress to and from their home when pursuing their daily tasks, obviating the toil unavoid- able had the way been obstructed by plants. Vege- tation in the immediate vicinity of the nest is likewise highly dangerous, in that it affords concealment to enemies at close quarters. It may be also that plants, seeing that they harbour damp, would be injurious to FIG 23. Pseudomyrma bicolor inhabiting Acacia comigera. the young ; and the roots might penetrate to the interior of the home and cause damage and incon- venience. The well-established and ordered roads between the formicary and the harvest-grounds, so characteristic a feature of the Texas communities, are absent, a fact that perhaps reflects to the credit of the ants in question. For while the vegetation surround- 142 ROMANCE OF THE INSECT WORLD CHAP. ing the clearings of the Agricultural Ant is dense, and pathways through it are an advantage, if not a necessity, generally on the American plains where the Occidents occur, the Gramma Grass (Bouteldua oligastachyd) prevails, which grows in tufts or bunches separated from each other by several inches, and the intervening spaces present only a smooth level soil, so that specially made roads are uncalled for. The cone is covered exteriorly, roofed as it were with a coating of pebbles to the thickness of about half an inch, not, or but sparsely, intermingled with the soil below, which is chiefly the natural soil of the surface, and constitutes the bulk of the mound. The stones are obtained from the subterranean galleries and chambers, whence the miners bring them up and distribute them on the top of the cone. These objects are of enormous weight as compared with that of the carriers, and their transportation from the interior beds to the outer atmosphere, by way of the sharp slopes or almost perpendicular surfaces of the galleries, must be a formidable task. The entrance or entrances to the dwelling, unlike those to the cone nests of the Agriculturalist, are not in the crater-like depression on the summit, but in the side of the cone and near the base. In width they vary from about three-quarters of an inch to three inches at their mouth, they are quite shallow, simply penetrating through the gravel to the inner soil. They open into the vestibule, and from it one or more galleries extend downwards through the cone, and communicate with the intricate system of passages, store-closets, nurseries, and living- rooms, mostly all situated beneath the level of the iv SOCIAL HOMES 143 surface of the ground. The Occident also shuts its gates in the evening, and on the occurrence of a storm ; it re-opens them late in the morning. Its labours it confines to the daylight hours. In form and plan the interior follows closely that of the Texas Agriculturalist ; in fact a striking resemblance in this respect exists among all these ants. The rooms, mere lateral expansions of the galleries, measure at most about three and a half inches in width, their greatest length is about five or six inches. The galleries are cylindrical, and of various lengths, and rarely exceed a diameter of half an inch. The apartments seldom extend beyond the limits of the " clearing," and chiefly underlie the cone itself. Dr. McCook ascertained that they descend to a depth of between eight and nine feet ! Many of them are granaries ; a single room has been found to contain seed to the amount of two tablespoonfuls. These deposits seem to clearly prove the harvesting proclivities of the Occident Ant, and beyond doubt the harvest is reaped for food. Dr. McCook, when engaged inexaminingthese formicaries, came upon rooms packed full of gravel, a circumstance attributed by him to a division of labour among the ants in their herculean mining. He conjectures that it is here the pebbles are carried by those labourers who cut them away from the soil in which they are embedded, when making the deep chambers ; while a second gang thence trans- ports them to the upper regions, and arranges them upon the cone. Some, however, Dr. McCook says, were not simple dumping-rooms to prevent stagnation of work, but veritable lumber-rooms, emmetonian 144 ROMANCE OF THE INSECT WORLD CHAP. garrets, for they had evidently contained the gravel for a length of time, and were apparently sealed up in the very midst of the nest. The nests of the honey-storing ants of Mexico like- wise consist externally of gravel-covered cone-shaped mounds, of diminutive proportions, attaining a height seldom more than about three inches (see Fig. 20). A single narrow tubular entrance-way descends through the mound and the earth more or less perpendicularly, to a distance varying from three and a half to six inches, and opens into the underground rooms and galleries. Arranged in several horizontal series one above the other, and intercommunicating by vertical passages, these extend chiefly in one direction from the gate. This ant is nocturnal in its habit of foraging for food, but does not bar its door in the daytime, the plan adopted by a night-wandering ant of Texas (the Cut- ting Ant, Atta fervens). The Honey Ant, however, does not neglect measures for safety ; just within the margin of the opening cordons of sentinels are stationed continually, whose business is to keep a sharp look out for enemies, and they appear to hold themselves in readiness during storms to repair damage or dis- arrangement of the pebbled roof. Disaster from this cause is slight, owing probably to the admirable choice of the situation for the nest. The honey-rooms, the abodes of the inflated honey-bearing individuals, are oval, conspicuously large, and vaulted, and will some- times rise from a height of barely three quarters of an inch at the walls to an inch and a half in the centre. The galleries are smoothed throughout ; but while the floors and walls of the honey-rooms are pressed well- IV SOCIAL HOMES nigh invariably, their ceilings present uneven surfaces, being in fact the natural condition of the soil after the sandy pellets and pebbles have been abstracted by the workers. The evenly-spread earth is adapted for gangways ; the roughness of the ceilings enables the honey-bearers to cling to them as to a perch. FIG. 24. Nest of a Tree Ant ((EcoJ>hylla smaragdina) from India. ^ In the homes of the Harvesting Ants of Europe (Atta structor and barbard] elevations above the soil are wanting. The large mounds frequently seen at the entrances are rubbish-heaps, the kitchen-middens of the establishments (see Fig. 21). Earth pellets and grains of gravel brought out in forming the subter- L 146 ROMANCE OF THE INSECT WORLD CHAP. ranean galleries occur in the heaps ; but they are com- posed principally of plant-refuse, such as the discarded envelopes of seed and grain, the chaff of grasses and the like, of which it is advantageous to get rid, in order to obtain greater space for the storage of the good food. The workers relegated to the duties of sorting the supplies, and casting forth those portions that they find to be useless, must labour with assiduous energy, judging by the speedy rise of the middens in the harvest season ; and where their position is sheltered from wind and rain, they often acquire considerable dimensions. On and about these ac- cumulations, plants foreign to the immediate vicinity sometimes flourish, having grown from seeds accident- ally dropped by the ants on their way home from the harvest grounds. The texture of the floors of the storechambers usually differs markedly from the surrounding soil. The horizontal rooms at times lie at great distances apart, but where the soil is shallow the galleries and granaries may be much crowded together. Some ants live in trees, and cut and chisel the wood in a wonderful manner. The best known is F.fuligin- osa* the emmet or jet ant, a brilliant black insect with pale reddish tarsi.* Its residences it constructs in the interior of old oaks and willows, gnawing the trunks into numberless stories always more or less horizontal, with a distance of about five or six lines between the ceilings and floors. The divisions are scarcely thicker than paper, a delicacy that is also attained in the vertical supports that apportion off the separate chambers. Communication in each story is r iv SOCIAL HOMES 147 by small oval apertures. In some cases the walls are reduced each into two pillars, rendering the apertures larger and rounder. When the work is still more advanced the holes become square, and the pillars originally arched at both ends are hewn into straight regular columns, giving a palatial aspect to the excava- tion. Further progress transforms these partitions into light cylindrical columns possessed of a base and capital which are arranged in colonnades, leaving a free communication throughout the whole extent. The rooms on or about the same plane when complete necessarily form a storey, but since they are hollowed out separately, though on similar plan, and the sides are chiselled away as time goes on, saving material sufficient to sustain the ceilings, the flooring cannot possibly be very level. This seems a boon rather than a disadvantage, for the irregularities appear to answer as cradles for the larvae. In roots sometimes, as in Australia, the nests look like charming net-work. The material carved be- comes black, as if smoked, due to exposure of the wood to the atmosphere, to some emanation from the ants, or to the action of formic acid (see Fig. 22). Wood-carving ants also infest the beams of houses, and imperil their safety. Two other tribes of Carpenters, F. cethiops and F. flava> the yellow ant, have the ingenuity to utilise the saw-dust that they chisel away. The former applies it to stopping up chinks and to the building of walls ; the latter, more skilled and in- ventive, composes entire stories of it stiffened and L 2 148 ROMANCE OF THE INSECT WORLD CHAP.- cemented into a kind of papier-mdcht with earth and spiders' web. Curious Carpenter Ants (Pseudomyrma bicolor], if so they may be termed, inhabit the strong curved spines of the Bull's Horn Thorn, a species of acacia, so called because the branches and trunk are covered with spines, set in pairs, which bear great resemblance to the horns of that quadruped. When the thorns are first developed, and are ready for tenancy, they are soft and filled with a sweetish pulpy substance. It the ants eat away, preserving the hollow hardened shell, within which they live and rear their young. Near the tip of the thorn an aperture is made for en- trance and exit. Additional doorways are not required, the partition separating the two thorns is burrowed through, so that one opening serves for both (see Fig. 23). The acacia does something more for the ants than provide them with lodging and a stock of food with which to commence to keep house. Its leaves are bi-pinnate,* and at the base of each two leaflets on the mid- rib a crater-like gland when the leaves are young secretes a drop of a honey-like liquid of which the ants are extremely fond, and they constantly run from one luscious mass to the other, sipping greedily. Nor is this all, the tree likewise provisions its guests with solid food in the shape of yellow fruit-like bodies, one at the end of each of the small divisions of the compound leaflets. Examined through the microscope they look like little golden pears. When the leaf unfolds the fruits are not quite ripe, and the ants are continually watching and investigating their iv SOCIAL HOMES H9 progress. Finding one sufficiently advanced they bite through its small point of attachment with the pinnule,* and, bending it down, break it and bear it off to the nest. Like the glands the fruits do not ripen at once, but successively, keeping the ants in protracted attendance upon the new leaves. In this way the formic visitors are brought to act as the standing army of the acacia, at the season of the year when it is fresh and sweet and most liable to attack, in return for all the comforts and luxuries that it bountifully affords. Provided with severe stings the protectors preserve the leaves from the browsing of mammalia, and from the ravages of much more dangerous enemies, the leaf-cutting ants ; nor can a caterpillar venture to approach without suffering from the weapons of the plant's body-guard. Even should the aggressor be man, and if he touches or shakes a branch, they swarm out, making free use of their jaws and sting. To all appearances they lead the happiest of existences. They fear no foe, they have ample food, and accommodation all that heart could desire. But there is a reverse side to this happy picture. In the dry season on the plains the acacias cease to grow, no young leaves are produced, and the glands, now old, secrete no delicious honey. Then the ants perish miserably from want and hunger, and many of the thorns become depopulated. Again, when the rains set in, the buds burst forth with all their dainties to the ant palate, and accordingly once more the creatures multiply. Both in Brazil and Nicaragua the flower-buds and young leaves of numerous plants are exempt from the ISO ROMANCE OF THE INSECT WORLD CHAP. destruction of herbivorous insects and mammals through the presence of their honey glands, whose primary object is to attract the guardian ants. Among others many epiphytal* orchids and species of Passi- flora may be mentioned, but they provide no house- room for their warders. On the other hand the Cecropia* or Trumpet Tree of Central America, equips ants with a house, but no food. The absent necessary the tenants furnish themselves with by means of Coccidcz, or scale insects, which they intro- duce into their home, and keep in their cells within the tree. From these lodgers a sweet liquor is ob- tained, and the Cocci in turn find their nourishment in the plant's juices. The stem of the Trumpet Tree is hollow, and divided into cells by partitions which extend across the interior of the trunk. The ants gain admission by boring a hole from the out- side ; subsequently they pierce the partitions and get the run of a large space. In her own royal cell the queen of the community resides, surrounded by a special bevy of Cocci, who yield her the requisite sustenance. The eggs, the grubs, and the pupae, have likewise their private apartments. In some of the Melastomce ants occupy the pouches on the petioles* at the bases of the laminae. As in the previous instance, Coccidce are taken for the supply of food. The hosts, on their part, guard the leaves in return for shelter, and shield their attendant Coccidcz from the attacks of other animal forms in the common habitation. Unfortunately many of the exotic ants have been only slightly studied in respect of their habits, iv SOCIAL HOMES 151 and their remarkable architecture has been allowed to pass without the investigation that it merits. Among kinds neglected must be included species of Crematogaster. When these run about they hold their abdomen high in the air, so that it curves backwards and overhangs the thorax, whence is derived their title signifying "hanging-belly." In the Brazils a species popularly called the Negro Head makes a strange nest, as round as the negro's bullet-shaped head, and exteriorly covered with pro- jections, suggestive with a little stretch of the imagi- nation of the African's close woolly hair. It is pensile on trees, and might easily be mistaken for the pensile home of certain wasps. Its internal arrangements prove to be more elaborate, for it is ramified with multitudinous covered passages inter- lacing intricately, but all leading to the interior cells. Formica elata and Myrmica kirbii also carry their abdomens erect, and both build on the branches of trees and shrubs. The nest of the former is a wonder- ful construction of earth mixed with leaves, which in some cases are exchanged for minute vegetable hairs. Myrmica kirbii makes a habitation of a congeries* of the excrement of cows and mules spread out into a multitude of thin folia, which are placed one upon the other in a wavy or scalloped manner, like the tiles of a house, leaving numerous arched entrances beneath the flakes, so that although the insects can creep into the nest, no water can enter. Over the summit is stretched a very large flake in one unbroken sheet, like a skull-cap on a man's head, which acts as a general roof and projects 152 ROMANCE OF THE INSECT WORLD CHAP. on all sides beyond the circumference. The edifice tends to become spherical or balloon-shaped ; its size is about that of an ordinary foot-ball. A vertical section presents an innumerable number of irregular cells, composed of the same substance as the exterior. Towards the centre they are more capacious than near the surface, and have been found to contain insects in every stage of development. These nests were discovered by Colonel Sykes in the Poona Collectorate, India, attached to the Kurwund shrub (Carissa carandas) and on the Mango tree (Mangifera Indica). No provision for the young appears to be laid up, and probably the house -supplies depend on daily quest. The ants are extremely small, barely one-fifth of an inch long. The nests of another extraordinary tree ant, (Eco- phylla smaragdina, are cunningly wrought with leaves, united together with web (see Fig. 24). One was observed in New South Wales in the expedition under Captain Cook. The leaves utilised were as broad as one's hand, and were bent and glued to each other at their tips. How the insects manage to bring the leaves into the required position was never ascertained, but thousands were seen uniting their strength to hold them down, while other busy multitudes were employed within in applying the gluten that was to prevent them returning back. The observers, to satisfy themselves that the foliage was indeed incurvated and held in this form by the efforts of the ants, disturbed the builders at their work, and as soon as they were driven away the leaves sprang up, with a force much greater than it would have been deemed possible for such labourers iv SOCIAL HOMES 153 to overcome by any combination of strength. The more compact and elegant dwelling of (E. virescens is made of leaves, cut and masticated until they become a coarse pulp. Its diameter is about six inches ; it is suspended among thickest foliage, and sustained not only by the branches on which it hangs, but by the leaves, which are worked into the com- position, and in many parts project from its outer wall. It may be at once distinguished from the nest of Crematogaster by its smoothness and regularity of surface. A species of this genus was discovered in Africa by Foxcroft, who observed that whenever the ants were molested, they rushed out of their house in such numbers that their pattering upon the papery covering deluded him into thinking rain was falling on the leaves above. In the forests of Cayenne, the nests of F. bispinosa are remarkably like a sponge, or an overgrown fungus*. The down or cottony matter enveloping the seeds in the pods of the Bombax ceiba is used for their construction, vegetable fibres that are too short to con- vert into fabrics, but which the ants contrive to felt and weave into a compact and uniform mass, so dexter- ously that all trace of the individuality of the threads is lost. The material much resembles amadou*, and like that substance is valuable for stopping violent discharges of blood. In size the nests generally have a diameter of eight or nine inches. The ant itself is little, and dark, and noted for two long sharp spines on its thorax, one on either side ; hence its scientific name of bispinosa, from the Latin meaning two-spined. Popularly it has been called the Fungus Ant. CHAPTER V. SOCIAL HOMES (continued). So-called humble-bees eighteen or twenty species in this country comparison of their habitations with the hive Description of nest of Carder the coping of moss interior dispersion of company and hybernation of females work of latter in spring Deep burrowers among British wild bees Honey-bees in the East Stingless Meliponae and Trigonas of South America and their homes supposed presence of several fertile females sentinels to guard the gates True social wasps their building material and dis- position of combs Particulars of home of common English wasp British tree-wasps the papery envelope Nest of hornet Description of combs of Polistes and Icarias with- out cover Apoi'ca has a cover but not distinct Card-board makers Wasps as honey-gatherers. LEAVING the marvellous structures of the hive out of the question, in this part of the world the only bee tribe that construct homes by the united labour of the society are the wild so-called Humble Bees. Every one is acquainted with them, big-bodied, and velvety, and heavy flyers, on the wing emitting that deep sonorous hum that has earned for them their popular title with its numerous variations. They arc known not only as Humble, but as Hummel, Bumble, CHAP. V SOCIAL HOMES 155 Dumble, Dumbledore, or Foggie, according to the dialect of the particular locality. Though all are denominated indiscriminately by this general term, H FIG. 25. Comb of a small honey bee (Apis Jloralis) from India, (a) The small cells for the workers ; (t>) the large cells for the drones. in this country in truth there arc over eighteen or twenty species of these bees, the greater part of which 156 ROMANCE OF THE INSECT WORLD CHAP. constitute one genus Bombus. Each differs some- what in detail of habits, and almost interminable varieties are exhibited as regards size and colour. Yet, except in the case of some of the more promi- nent species, they are not easy to identify ; naturally the popular mind recognises no difference ; therefore no distinct common appellations have been originated for them, and unfortunately it becomes necessary to make use of the scientific names. Their habitations are rude, the number of inhabitants too is small, sometimes not more than twenty, and rarely exceeds two or three hundred. Again, contrary to the custom of the hive, there is no single female who permits no rival to divide with her the affection and deference of her subjects, and who is set apart for one exclusive function. In the Humble Bee's colonies the males, females, and neuters* so-called, dwell on terms of amicable equality together, and the females share in the ordinary duties of building and providing for the needs of the house. The males, however, as in the hive, are fewer than the workers, and idle, and when once they venture abroad seldom return. The nest of B. muscorum is plentiful enough, but not easily found. Usually it is situated in open meadow r s and pastures, sometimes in hedge-banks where the soil is entangled with roots, at the borders of copses, or among moss-grown stones. It occupies a shallow cavity in the ground, perhaps half a foot in diameter, either selected ready-made or formed by the bees with great labour. Over the inconsiderable hollow rises a low vaulted dome or roof to a height v SOCIAL HOMES 157 rarely reaching more than three or four inches above the surface, and composed generally of fragments of moss cleverly woven into an admirable covering, made to harmonise with surrounding objects with the view of concealing it from curious eyes. Besides moss, the bee's favourite material apparently whence its name muscorum, " of the mosses," dead leaves, grass, fern-fronds, and other matters are frequently adopted where moss is scarce or absent ; but whatever the substance may be it is within easy reach, for the bee never attempts to transport any- thing from a distance. The material is prepared for roofing purposes in a manner similar to that of card- ing cotton or wool, or heckling flax. The process consists in the operator carefully disentangling the fibre, seizing it and drawing it through her jaws and forelegs, subsequently she passes it under her body by means of the remaining pair of legs, forming it as she does so into a small ball or bundle convenient for carrying home. The object of the dome is obviously to protect and hide the dwelling, which lies at the slight depth of an inch or two beneath the soil. Although the moss is laid down in considerable quantity it would be inefficient to exclude rain ; and as a rule a lining is added, a thick coating of grayish- yellow wax similar to that of which the breeding- cells are made, but of far inferior quality to the wax of the hive, rendering the interior water-tight. The entrance to the nest is in the lower part, and is generally a kind of tunnel or covered way, sometimes more than a foot long and half an inch wide, more effectually concealing the abode from observation. 158 ROMANCE OF THE INSECT WORLD CHAP. The occasional opening at the top seems solely for the admission of air and warmth ; by it the bees are never seen to enter or depart, and it is closed at night and in bad weather. On removing the domed coping of moss and bringing the interior into view, a different scene is presented from the delicate rows of hexagonal cells which go to form the finished workmanship of the vertical combs of the hive. In their place there are various irregular groups of oval pale-yellow bodies, arranged horizontally in a general way, the groups being more or less pressed together and connected by slight joinings of wax. These are not, as one might suppose, the work of the old proprietors of the nest, but the silken cocoons spun by the larvae for their pupae life, in like manner as the larvae of other bees. Some of them, chiefly those occupying the lower combs, stand open, indicating the completed develop- ment and escape of their former inmates. Those FIG. 26. Melipona bees gathering clay ; rom Bates. which are closed at their upper extremity include immature pupae not ready for their final metamor- phosis. Besides these bodies, several amorphous* v SOCIAL HOMES 159 masses of dark-coloured wax are perceived, of flattened globular shape and various dimensions. Opening them, a number of eggs or grubs encircled with a paste made up of pollen and honey are found. These are the true breeding cells, formed mostly by the mother, who deposits her eggs here, and stocks the young FIG. 27. Home of Vespa Norwegica. with the supply of sweet food. The larvae that are hatched from the eggs exhaust the store given them before they are full-grown ; when it is consumed the mother furnishes her little ones with daily provision until the days of their larvahood are accomplished, and they spin cocoons for the coming helplessness of pupse. The number of eggs or grubs contained in one 160 ROMANCE OF THE INSECT WORLD CHAP. spheroidal* mass varies from about three to about thirty. Intermingled with the breeding cells and cocoons at certain times of the year, especially on the sides and in the middle of the nest, are likewise small goblet-like vessels filled with a very pure honey. They consist of cocoons deserted by the pupae, but it falls to the lot of the workers to refurbish the disused cells for the fresh purpose. Fragments of silk left hanging from the orifices at the emergence of the young bees they cut away, and, after shaping the rims a little, they strengthen them by rings or elevated tubes of wax, completing the renovation of each cup by the addi- tion of an internal lining of the waxen material. The stored honey may serve to moisten the food of the larvae, probably it also acts as nourishment to the working colony when prevented by unfavourable weather from seeking it abroad. Occasionally the bees construct receptacles or honey-pots entirely of wax. As winter approaches these communities break up and perish, a few fertile females or queens alone surviv- ing, the Methuselahs of their short-lived race. In utter solitude and in a state of torpor they lie in any convenient crevice ; in the rotten wood of decaying trees, under moss in woods, or turf, in haystacks, in the eaves of barns and outhouses, seldom, if ever, in the nest that they have inhabited. Awaking with the sunbeams of returning spring they commence a life of unceasing labour. Diligently they search for fit spots for nest-building, or, in default of suitable cavities that would in some degree abridge their toil, each bee hollows out a small hole for herself. The v SOCIAL HOMES 161 moss-dome being built, she collects quantities of pollen and honey, and, when the hoarded mass is sufficient for a beginning, proceeds therein to deposit some eggs. In a few days the larvae are hatched, and immediately set to work to eat the food on which they are cradled. Soon they become full-fed, and spin their cocoons, and rapidly undergoing their transformations they gnaw off the tops of their cells and shortly emerge as perfect insects. Invariably the first batch of offspring are workers, who aid the queen in forming the colony. On them devolves the enlargement of the nest, and they assist in the up- bringing of their juniors in the home. Young males and females do not appear until the season has considerably advanced. B. lapidarius, " the red-hipped humble " of Shake- speare, one of the most abundant of British Bombi, has a preference for making its nests beneath stones. Under compulsion of untoward circumstances, it forms residences in the earth, like the common Humble Bee. The burrows of B. terrestris are often of great depth ; no moss cover is manufactured, but the roof is lined with layers of wax. In internal construction these nests do not differ from the nest of B. muscorum. As a rule deep burrowers have a population twice as numerous as the more surface- building Carders. The latter are greatly influenced by the weather, their numbers being much diminished by a wet unfavourable season, but, speaking generally, an autumn company seldom exceeds a hundred all told. Of all the Bombi the common Humble Bee is the most prolific, and its homes contain more indi- M 162 ROMANCE OF THE INSECT WORLD CHAP. viduals than those of any other species ; between three and four hundred members sometimes apper- tain to one nest. This is a sparse society as com- pared with the hive ; but the honey-bee is much smaller, and its cells in which it is hatched and nurtured are correspondingly minute. Those of the Humble Bee are not only large, they are set very irregularly and occupy extensive space. Cells capable of holding an assemblage of three or four hundred form a great group, and require a cavity to contain them enormous in proportion to the size of the excavators. Underground-builders seem of more vindictive character than the Carders, and appear to resent interference with some ferocity. Nests of the Carders, on the other hand, may be taken almost with impunity. The Honey Bee (Apis) is not wild in this country ; in the East, its supposed original home, it exists in this state in great abundance. Apis indica and nigrocincta, species probably in general domesticity in India, build in hollow trees or crevices in rocks ; as opposed to Apis dorsata, which likes to hang its combs from the undersides of boughs of trees or rocks. Apis dorsata is perhaps the best known of Indian honey-bees, and is extensively cultivated in the Himalayahs. Probably rocks are its favourite natural nest-sites, where it is sheltered from the weather and the attacks of bears. In the hills, as every one knows, these quadrupeds make almost any effort to get at the combs and honey in trees, caring little for the stings of the defrauded creatures. Numbers of nests constantly hang from old buildings, v SOCIAL HOMES 163 such as the Taj Mehal at Agra, which is much dis- figured with the pendant combs. Many attempts to remove them have been made, but no sooner is a nest destroyed than it is quickly renewed at a few feet distant. A. floralis, a beautiful little bee, nidifies on the branches of orange and lemon trees, and garden shrubs generally (see Fig. 25), occasionally in the interior of mud walls, the cavities between bricks, or in holes excavated by the termites or white ants. Immense clusters of honey-combs hang in the caves of Salsette and Elephanta, in the clefts of the rocks and the recesses among the figures. So abund- ant are the bees, they have been known to put intrusive visitors to the rout. From Europe, long ago, the Honey Bee (Apis) was imported into the West India Isles and the northern provinces of South America, where it exists at the present day domesticated, and at large in the woods and forests. Not a single species of this restricted genus is indigenous to the country. In North America the nearest ally as regards its habits is the Humble Bee, of which no fewer than forty species are known. The tropics possess considerably better substitutes in the genera Melipona and Trigona, the celebrated stingless honey-bees of South America. The Meliponce have remarkably long legs, they are short and squat, generally much smaller than the hive bee, some in fact are nearly as tiny as midges, and extremely irritating for getting into the nostrils and about the head. Though they have no sting, or rather their sting is feeble and they use it seldom whence the Spaniards call them angelitos, or little M 2 1 64 ROMANCE OF THE INSECT WORLD CHAP. angels they appear capable of biting sharply. Their colonies are often far more numerous than those of the Apides, and several fertile females are said to live together in harmony. They construct homes in suitable crevices in hollow trunks, or in perpendicular banks, even in cavities of rocks by the sea-shore. The form of the habitation varies according to the species, but most kinds of Meliponce are masons. It would appear that the Old World has produced far more advanced forms of animal life than the tropics of the New World, and these bees offer no exception to the rule. Their nests may be of enormous pro- portions, and immense quantities of pollen and honey are stored, yet their architecture is very inferior to the skill exhibited in the European hive. The Melipona are as prodigal of wax as the others are sparing of it. Their comb is composed of a single series of alveoli * applied laterally to each other, and not of two strata or layers placed end to end. Generally they are oblong, showing only here and there an approxima- tion to the elegant hexagonal shape, and appear to be destined solely as the residences of the larvae. The honey is stored apart from the brood-cells in great waxen vases or vesicles, with thick and strong walls. Some of these sacs have a diameter of an inch and a half, or about as large as a pigeon's egg. The most numerous and interesting masons, Meli- pona fasciculata, are about one-third shorter than Apis mellifica. Little crowds of the workers are constantly employed in gathering clay, and the rapidity and pre- cision of their movements while thus engaged are wonderful (see Fig. 26). With the material collected v SOCIAL HOMES 165 they construct a wall, often in the hollow of a tree, filling up the crevice with the exception of a narrow orifice. One species, still more determined to secure safety and privacy, in addition to blocking up the gap, fashions a neat tubular gallery of clay outside its doorway; the tube has a trumpet-shaped mouth, and the particles are kneaded together with some substance of viscid consistency. At the entrance a number of the pigmy owners are always stationed, apparently acting the part of sentinels. That these bees appoint sentinels to guard their gates is a fact of frequent observation. They sedulously watch the out- goings and incomings of their fellows, and seem now and then to be relieved on duty. A relief-guard pre- sents itself every twenty-four hours according to the Mexican cultivators, but no unreasonable doubts may be entertained of such regularity. At all times the sentinel-bee occupies the hole leading to the interior, and as often as a worker desires to enter or to quit the nest, momentarily withdraws within a small cavity on the side of the aperture, resuming its station with sur- prising alacrity whenever the individual has passed in or out. In Jamaica, where probably the species are simi- lar, if not identical with those of Mexico and the Brazils, no fewer than three sentinels have been* seen oppos- ing the entry of the black ants that infest forest trees. The assistants stood behind their principal, heads downwards, and, clinging to the upper arch of the entrance, they gazed upwards, steadily scanning several ants within the crevices of the bark, prepared to rush in if the guards remitted their vigilance for one moment. The active ants paced upwards and down- 166 ROMANCE OF THE INSECT WORLD CHAP. wards in lines, eager for the booty, but were allowed no greater satisfaction than a rapid reconnoitring of the doorway. 1 Bees of the genus Trigona hang their combs out- side on the branches of trees, at the very summit of the tree and the end of the slenderest twig, so as to be out of the reach of the monkeys. In shape the nests are like a large pear, and, judging by the dimen- sions of some and the multitudes inhabiting them, it seems hardly possible to doubt that they contain several prolific females, as in the Meliponce. While the Meliponce are chiefly, or exclusively, restricted to the warm regions of the New World, the Trigonce extend into India, Africa, Australasia, and to the Isles of the Eastern Archipelago. The honey of some species is sweet and altogether excellent, that of others is black and sour and quite worthless, but dark honey, as of Trigona ruficornis^ may be well flavoured. The wax too, is sometimes very dark and unctuous,* though susceptible of being whitened somewhat by bleaching. The hives for domesticating the Meliponce in Mexico are primitive, and follow closely the habitat of the bee in a state of nature, being simply a portion of a hollow log of between two and three feet long; a hole is bored into the interior through the sides midway down the length, and the ends are stopped with clay. They are usually sus- pended on trees in a horizontal position, and are quickly taken possession of by bees. While some of the combs are vertical, others are situated hori- 1 Naturalist's Sojourn in Jamaica. Gosse. SOCIAL HOMES 167 zontally, the cells of the latter being the most numerous ; all are ranged together at some distance from the opening. Externally to these are the clusters of sacs for the honey, affixed to the wood of the cavity by processes of wax, or to each FIG. 28. Comb of Polistes tepidus, Fabr. , with other and frCQUentlv centre pedicle ; from Saussure. J placed side by side ; the disposition of a group as a whole has some resemblance to a bunch of grapes. Taking advantage of the irregular position of the sacs, the cultivators abstract the honey by removing the clay plug from the bottom of the hive, and secure the riches without injuring, almost without disturbing, the inmates. The end is again closed, and the bees, robbed of their treasure, lay in a fresh store. The true social Wasps, which are arranged in one large family, the Vespidce, form communities.whose architectural la- bours will not suffer on compari- son even with those of the inhabitants of the bee-hive. In fact, for dainti- ness and delicacy the nests of many of the Vespidce constitute the most beautiful examples FIG. 29. Comb of Polistes cctnadensis, Linn, inverted, with lateral support and irregular cells many still containing nymphs ; from Saussure. i68 ROMANCE OF THE INSECT WORLD CHAP. of insect architecture. As with the bees, the great object of their industry is the safety and upbringing of their beloved young, and in like manner they construct combs for their reception, consisting nearly always of hexagonal cells. The building material they employ, however, is totally dissimilar to wax, and the plan of their city differs from that of the hive. These nests show many discrepancies, and their situations vary; but though they are heteroge- neous in detail, in the essential and most important points they are all alike. The common English Wasp (Vespa vulgaris) is a handsome insect, much disliked for its fond- ness for everything sweet and its formidable weapon of defence. The gardener especially holds it in abhorrence, on account of its depredations on fine ripe fruit. Still it is more a predacious than a vegetable feeder, and the evil it commits in respect of the peaches, and so on, is perhaps more than counterbalanced by its good works in ridding us of many a tiresome fly and similar pest. Usually situ- ated in a cavity underground, the nest is a marvel of ingenious industry. Of more or less globular shape, and about sixteen to eighteen inches long by twelve or thirteen broad, it is inclosed in a coating of material some half an inch thick, like coarse brown paper, though not so tough, made up of numerous thin leaves or laminae, which do not touch but have small intervals between them, and is evidently in- tended to prevent the earth from getting among the combs inside. If this external portion is removed the combs are exposed, generally from twelve to v SOCIAL HOMES 169 fifteen in number, circular, and of different sizes, and disposed horizontally in distinct and parallel tiers one above the other. Each consists of an as- semblage or layer of cells of papery stuff like the covering, their mouths directed downwards, so that their upper ends or bases, which are slightly convex, together constitute an almost level floor, on which the wasps conveniently pass to and fro in attendance on the young hanging in the comb of cells immediately above. These terraces are supported by fixture to the sides of the nest, and each is attached to the pre- ceding one by cylindrical columns or pillars, of a compact paper. Access from tier to tier is gained by openings between the walls of the combs. At the bottom of the nest two main holes exist, the entrance and exit ways common to the community. A covered road leads from the surface to the subter- ranean dwelling, often a long and tortuous path, an approach carefully concealed though well-known to the miners. This wonderful structure arises from a small begin- ning. In the early spring a solitary wasp or two may be observed here and there, flying neither high nor fast, but plainly on a tour of inspection of the earth-banks, scrutinising into the opportunities they offer for the formation of a home. These are females who have just awakened from their hybernation. At last the wasp meets with a crevice to her mind, the abandoned burrow of a field-mouse maybe, or of a mole, or perhaps the forsaken tunnel of some large burrowing insect. She examines it in every par- ticular, she fusses in and out, she appears to delibe- i;o ROMANCE OF THE INSECT WORLD CHAP. rate ; eventually she assumes proprietorship, and pre- pares to enter into possession. The first thing to be done is to form a chamber to her liking at some dis- tance below the surface ; so she breaks away the soil, and carries or pushes it out bit by bit. The cavity being ready, the next item of procedure is to lay the foundations of the house to be included, which con- trary to the usual custom of builders is begun at the top. Taking leave of the home-site for a time, she flies off to a wooden post, or rail, a window-frame, or some such thing, where with her jaws she busily gnaws away the fibres until she amasses a little bundle. She kneads, and triturates, and moistens the filament with saliva, reducing it to a homogeneous paste or pulp, a kind of papier-mac] te. Back to the nest she hurries with her burden. Here the ductile mass is made to adhere to the centre of the ceiling of the chamber by her jaws and forefeet ; meanwhile she clings to the ceiling by her two last pairs of legs. Supply after supply is acquired and placed, until a pillar about half an inch long, pendant from the ceil- ing, is complete. At the extremity of the pillar, with the same material and in like manner, she attaches three very shallow cylindrical cup-like cells, in depth about a tenth of an inch. They hang bell- wise, and in each she deposits an egg. The young things require protection, and over them the mother simultaneously constructs a roof, umbrella-shaped, and made of paper as the cells, but laid differently, the length of the fibres being almost at right angles to the middle of the proposed comb. On either side of the first group cells are added close together on SOCIAL HOMES 171 the horizontal floor, eggs are laid in them, and in correspondence with the enlargement the roof is extended. The covering is of considerably rougher FIG. 30. Nest of Icaria variegatci, texture than the cells, and no attempt is made to smooth the surface. By this time the three eggs that were first laid 172 ROMANCE OF THE INSECT WORLD CHAP. are hatched, and the larvae have to be fed ; they increase in size, and their cradles must needs be bigger. The poor mother finds plenty to do, she has to construct cells, to lay eggs, to enlarge the cell- walls, and to seek for food wherewith to satisfy her more advanced offspring. Soon, however, the worst of her troubles are over. The first-born become full- grown, cease to feed, and inclose themselves within their cells, each in its own white silky cocoon with convex cap, and shortly emerge as perfect insects. The work now goes merrily on, for these young wasps are workers, who take upon themselves the arduous share of the labours of the hive. They increase its ex- tent, and become nurses to their younger companions, while the mother does little but lay eggs in cells as fast as they are made. As time goes on brood after brood of recruits is added to the army of workers, new cells rise quickly, and are as quickly supplied by the mother, and before long the first cell-terrace is com- pletely filled. Various pendant pillars, similar to the foundation pillar, now appear on the underside of the comb at the angles where these cells meet. To their extremi- ties cells are caused to adhere, and by dint of additions they soon all unite and form a second terrace below the first, the distance between the two tiers being about half an inch, or equal to the height of the inter- vening columns. A third, a fourth, and a fifth tier are constructed, and the roof or walls of the building are constantly brought down lower. The cells com- posing the foundation terraces are amongst the smallest in the completed nest; they are too small to v SOCIAL HOMES 173 admit the head of the female, who when she gives the inmates mourishment feeds them entirely from the outside. It follows that the wasps bred in them must be of less size than the mother, they are indeed all un- developed females or workers. The cells of the next few tiers are much larger, being the breeding-places of the males and females. Thus, then, workers only are brought forth early in the season ; the males are hatched subsequently, and the virgin females latest of all. The terraces gradually increase in diameter up to the fourth or fifth, when they usually decrease slightly, and in exact conformity with this formation the covering is constructed. They are not perfectly perpendicular but somewhat raised at the corners, so as to form a trifling concavity in the centres of the floors. Though the cells are cup-shaped at their bases, they become beautifully hexagonal as they rise in height, or rather in depth, particularly at the middle of the combs ; a large nest contains from about 7,000 to 10,000. Each is believed to be the birthplace of three generations, with the exception of those intended for the males and females which are probably the cradles of but one brood. Wood fibres seem a flimsy substance of which to make such an edifice, and by which to sustain so great a multitude, but as a fact the walls are very strong, and the hexagonal shape of the cells affords mutual support. Scarce is the building finished ere it begins to show signs of dissolution. The summer is over, the several broods of workers have passed through the cells, and the single generation of males and females have become mature. The males are dead, the workers 174 ROMANCE OF THE INSECT WORLD CHAP. likewise desert the home and die, and the majority of the females, a few only seeking refuge in cracks and holes, where they survive the winter, and live to be queens and founders of future colonies. Out of a vespiary holding three hundred females in the autumn, barely ten or twelve will see the spring. Before deserting the cells should any grubs remain un FIG. 31. Nest of a Brazilian Wasp (Apotca pallida). developed, the workers, apparently prescient of their coming doom and aware that there will be none to discharge the duties they must themselves lay down, carry forth the helpless nurslings and forsake them, arrant cruelty on the face of it, in reality an act of mercy, substituting a quick death by exposure, or by falling a prey to some creature's appetite, for the slow v SOCIAL HOMES 175 lingering death by starvation that would be theirs were they left neglected within the nest. Occasionally V. vulgaris dispenses with a burrow, and builds from beams in the corners of outhouses ; under a thatched roof is also a favourite locality. Among the British Tree Wasps, which habitually make pensile nests, the best known is Vespa Britan- nica. In the South and West of England it is rare, but is plentiful in Scotland. Its lovely globe-like dwellings it boldly suspends from the extremities of branches of trees and shrubs, chiefly the fir and the gooseberry. V. sylvestris has a wider distribution, but is scarcely so common, and is a burrower at times. The outer shell or envelope of the pensile nest, very fine and choice in relation to the covering of the subterranean combs of the common wasp, is made of a smooth and white-gray paper, its individual flakes being sharply defined. It is impervious to water, and protects the combs admirably, to which however it is never attached. The opening is at the lowest part, and underneath, and is sufficiently large to give free entrance and exit. For beauty, delicacy, and utility, the Tree Wasp's nest is unrivalled (see Fig. 27). As the population of a wasp community increases and the cells must be augmented, laborious is the undertaking, since it necessitates that the inner sheets of the covering be cut away to make room for the greater size of the comb, or combs, while faster than these are removed additional layers are formed externally, to maintain, and even to slightly add to, the thickness of the walls. Thus is the human i?6 ROMANCE OF THE INSECT WORLD CHAP. architect careful to proportion the thickness and con- sequently the strength of his walls, to the magnitude of the building about to be erected. This method of enlargement of the nest-cover obtains among the species sylvestris, Norwegica, and rufa. In the case of the subterranean dwellers, vulgaris and Germanica, and among the hornets, the mode consists not in the superposition of layers, hollow pieces of material are formed, blisters, as it were, are raised all over the plain outer surface as left by the queen when she renounced her architectural labours. Blister after blister is placed one above the other, and, as in the former instance, the underlying matter is cut away nearly as quickly as the fresh formation is added. The material removed is not discarded as useless, but worked up afresh ; as a fact, this is performed by the act of removal. Subsequently it serves both for new cells and for additions to the outside. The alteration of a subterranean dwelling involves the greatest toil, for besides the changes necessary in the envelope plainly the area of the nest-cavity must be enlarged. Care is always taken to keep free a clear, though tiny, space between the papery-shell and the earth interior. The fabrication of the papery sheets that together make up the powerful envelope is a perfect work of art. One is astonished at their resemblance to our own gray paper. This paper is simply thinner, more silky, more smooth and glossy ; it offers great analogy to papers made by island savages from the bark of trees. When a wasp bears a fibrous ball of paste to the nest, and adds it to that piece of the covering on v SOCIAL HOMES 177 which the builders are engaged, it draws out the little mass with its jaws and feet into ribbon-like form along the edge of the wall, reducing it to the requisite thin- ness much as a mass of metal is pressed by the cylinders of the rolling-mill. During the operation the wasp invariably walks backwards. The tongue then adds the finishing touches, giving the paper a brightness and polish. A colony labour simultane- ously, and the workers bring their morsels to the same point of the nest, resulting in a regular trans- verse zone. Every nest shows these zones of forma- tion of the paper, sometimes not very distinct because they vary simply from darker to lighter tones of gray ; but often the stripes are quite pronounced and of dif- ferent colours. The wasps go forth solitarily in search of building material no doubt, and must bring in stuffs of various sorts. But when one finds a good working- stock, others seem to become cognisant of the fact and hasten to the spot, and the zone constructed will be of a particular colour. If, for example, a birch be the object attacked, the zone will be white ; if a poplar, the zone will be green. The same wasp, however, it has been observed, does not always bring in a load of the like colour. But she seems sensible enough not to deposit her lump behind material different from her own, she puts it against similar substance, and mixed bands are never made. The separate sheets or leaves of paper are not complete sacs, shutting in the combs as an egg is inclosed in its shell. They are limited in size and imbricate* with one another, and are kept in place and are in contact together merely N i;8 ROMANCE OF THE INSECT WORLD CHAP. at the points of imbrication. Flat cell-like spaces occur between them, except towards the summit of the nest where the envelope forms a thick- ish compact mass. The points of fusion of two successive layers never fall precisely the one above the other. By this mode of construction each layer of paper lies on a stratum of air, a disposition that withstands inclemency of weather. The. whole of the exterior layers may be soaked with rain without soiling in the slightest the leaves beneath. The paper of Vespa, though sticky, is not varnished, and wets easily. But it will dry in the sun, and not be in the least deteriorated. The nest of the Hornet ( V. Crabro)^ tolerably plentiful in many parts of England, is identical in character with that of the wasp. It is larger than the wasp's nest and the cells are larger ; its paper is rougher, and the columns that support the comb- tiers are higher and more massive, the central one especially, which is about twice as thick as any of the others. This insect does not favour the under- ground for a dwelling; it lodges in out-of-the-way corners in thatch or under the eaves of barns and out- houses, and is extremely partial to save itself trouble by building within old tree-trunks hollow from decay. The cavity need not be particularly large when it is adopted, for the hornet is liberally provided with the means of excavation in its sharp and powerful jaws. A nest so situated has no definite papyraceous envelope, the hornets seem to understand perfectly that the wood with which the combs are surrounded affords sufficient protection in itself, and they provide v SOCIAL HOMES 179 coverings only for those parts that are more or less exposed. Thus the entrance hole is always obstructed by leaves of paper which close it as much as possible without impeding the way out. Under other circum- stances hornets are at great pains to shelter their combs within a papery coating of many thicknesses, an envelope that constitutes an excellent example of the appearance produced by obtaining strength of walls and large dimensions of comb-tiers by constant exterior additions of puffed-out papery cells. They open on the surface of the nest, where they are very regular, by narrow entrances, always directed down- wards, the object being doubtless to prevent any substance falling from above from penetrating inside. Saussure believes the use of these entrances is to permit the access and circulation of air amid the vacuities of the envelope, for the purpose of drying the papery leaves each time that they are wetted and softened at the surface. The real entrance to the nest is at the inferior extremity, as in other Vespse that nidify in the open atmosphere. When hornets take up domicile within a hollow trunk they frequently seem to make no use of the large hole of the tree, but go to the trouble of digging a gallery through some undecayed portion It assumes a winding direction, and probably protects the nest from intrusion. In the opinion of Reaumur, hornets can distinguish a rotten tree, to all appearances healthy. They bore through the sound wood to reach the interior, and gnaw the cavity to suit their con- venience. This penetration of the living matter is difficult, and the hole is never enlarged beyond the N 2 i8o ROMANCE OF THE INSECT WORLD CHAP. limits necessary to admit of free locomotion in and out. The materials removed in excavation go to form the cells, and the coverings, what coverings there be. Some of the nests are of great size, even three feet long, and wonderfully fragile, due to the choice of rotten wood for the manufacture ; whereas other wasps scrape their vegetable fibres from moist living sources, and make a firm and tenacious structure. The hornet's paper is very friable, and excessively yellowish or russet-coloured, widely different from the silvery-gray composition for instance of Vespa Norwegica. In a sense the hornet is more indefatigable than the wasp. At night the wasp retires within doors for sleep, but if the moon be up, the hornet steadily pursues her tasks ; even when the moon deserts her, she is prone to do night-work. Leaving Vespa we pass to the Polistes, a group of wasps with elongated bodies and the first segment of their abdomen* drawn out into a long pedicle. This genus is essentially exotic, though it occurs sparingly in England. Their system of nidification, while in- ferior to Vespa, far exceeds that of the latter in diversity of plan. The nests differ in shape, and are very variable as much for size as for mode of attach- ment, but the combs are always destitute of any covering envelope ; the young, however, are perfectly safe inside. The position of the nests is not purely horizontal, but oblique* or vertical, so that they are adapted to casting off the rain. If, on the contrary, the cells faced upwards they would fill with water ; were they directed downwards the water must lie on their bases as on a flat roof, and in course of time v SOCIAL HOMES 181 must sink through. The insects take the further precaution of turning them towards the north or north-east, because during the summer and autumn in these climates the strong cold winds, and those that bring rain, usually come from the opposite quarter. Their impermeability is increased by a varnish, probably a glutinous liquor, secreted by the wasps, which is well rubbed on to the papery sur- faces. Though each species seems to have a form of nest which it favours, still one hard and fast line is by no means adhered to ; seemingly the Polistes approve of the maxim that circumstances alter cases. Many of the dwellings are circular or approach the round (see Fig. 28), some are as though compressed, some oval, some simply composed of one or two long lines of cells, some are eccentric, forming at first a triangle which is finished with a rounded end. The solid foundation of the comb and the strong slender pedicle* that maintains it may be central ; in other cases it projects entirely from one side of the support (see Fig. 29). The nests never reach a great size, often there is only one tier ; additional combs are attached by pillars or foot- stalks as in Vespa. The cells are roundish, and remarkable in that their bases are a trifle smaller than their mouths, a divergence hardly noticeable in the single cell, but which produces a spreading outline when a number are massed together. Those in the middle are large and long, and generally closed, indicating that the larvae are within, undergoing their transform- ations to perfect insects. As a rule the peripheral 182 ROMANCE OF THE INSECT WORLD CHAP. cavities are much shorter, open and empty, indeed one would imagine them to be abortive, and too small to be of any use. These are mere rudi- ments or outlines, and originate in a thrifty habit of the wasps of constructing not only cells that they wish to fill, but of preparing others to come in handy by-and-bye. Within the little cups, the bottoms of future cells, eggs can be laid, and later on the walls can be lengthened. These sketches, several deep, sometimes form a ring round the great cells, or comb properly so called. They are of advantage in permitting of rapid additions to the nest, in a sense they ensure its well-being by lessening the bad effects of any shock or blow, and they alone would be flooded in the event of pene- trating rains. They are less well proportioned than the mediate cells, even the form of the nest as a whole indicates that they are the most oblique, the most divergent, and difficult to construct. Probably to this cause must be attributed the variety to which the nests of all kinds of Polistes are subject. There seems reason to believe that the individuals bred in the lateral apartments are neither so large nor so perfect as their kindred fortunate enough to enter the world in the more beauteous central cradles. Polistes aterrima forms its cells with beautiful regularity and sets them in a very peculiar manner, two deep on the same horizontal floor, and in a couple of pendant rows. They open downVards, but are not quite perpendicular, they incline a little alternately to either side. Each is placed rather lower than its fejlow, producing a striking general effect and one v SOCIAL HOMES 183 easily recognisable. Slight and perishable as they appear, the rain may fall in torrents without wetting them. Over the whole the wasp lays a thick coating of a blackish but transparent varnish, which renders them waterproof ; it also binds the group firmly together, and gives it a high polish. The small dimensions of the nest lead one to think that these wasps form societies of a different nature from those of immensely populous communities: Towards its basal end the cells become small, a diminution that arises simply from the fact that they are yet incom- plete ; originally the upper cells were in the same unfinished state. It is incorrect, though very natural, to suppose that the higher and larger compartments are for the future males and females, the lower and smaller ones for the breeding of the workers. The similarity of completed cells raises important ques- tions. Are these societies true societies, do the males and females belong to the same brood, are they of like size, and nurtured in the same cells ? Possibly the sexes are reared in separate establishments, on the principle of unisexual or dioecious* plants. Not the least extraordinary of the wasps are the Icarias, a genus that extends through most of the warmer regions of the world, specimens having been taken in Africa, India, China and Australia, and in many parts of the Asiatic Archipelago. Like the Polistes, their nests are attached to leaves, stalks, or branches by a single footstalk, composed of the same papery material as the cells. Though slender it is hard, tough and solid, and the strength with which it is fastened to the tree or plant is surprising, enabling 184 ROMANCE OF THE INSECT WORLD CHAP. it to uphold considerable weight. At the end of the petiole usually a single cell, its mouth directed down- wards, is fixed ; the rest of the nest consists of a double series of lateral cells until the group is complete. Those nearest to the foot-stalk are the largest and most perfect, since they are finished first; towards the other extremity the cells gradually diminish in size, and at that point they are only just begun. As a whole they are well-defined hexagons, their colour is often a rather dark yellowish brown, preventing them from being conspicuous in spite of their curious pro- jection. The cell-masses are small, so that the societies must be restricted. Possibly each group is the work of a single female, who confines herself to raising her own progeny which escape as soon as they are hatched. The nests are frequently numerous in the same spot, and each society may set up a number of separate homes in the vicinity of one another. Perhaps in this genus, as among the Polistes, workers are wanting (see Fig. 30). The architecture of Apo'ica may be compared with that of Polistes. If one were to impaste a great canopy-like mass of cellular matter to the dorsal face of a circular cell-group of Polistes, then one would have a nest of Apo'ica. The comb opens downwards, its upper surface is convex, not that the cells group themselves in a cluster round a central point, a mode often giving birth to convexity of surface, the canopy or ceiling is itself hemispherical, and to its inferior face the group is attached. The cells are of about equal length, thus the thickness of the nest is almost the same throughout, and the undersurface is generally SOCIAL HOMES 185 more or less concave, so that the edges of the sphere project and afford a certain amount of protection to the middle portion. The cellular canopy is a spongy substance, not unlike a lather of soap; in reality it FIG. 32. Wasp's Nest (Chartergns apicalis), interior and exterior. is a species of paper, and when torn or cut offers some resemblance to cotton-wool. It is usually of a yellowish or tawny* colour, and somewhat gummy and glossy. This paper is kneaded and worked up by the manufacturers until it becomes uniform, and 1 86 ROMANCE OF THE INSECT WORLD CHAP. shows no trace of the successive sweeps of the insects' jaws, so plainly exhibited in the papery coverings of the English wasps. The thick hemispherical, cap is varnished on the exterior, rendering it weatherproof ; its use is clearly to protect the bed of cells against rain and any body that might strike them in falling from above ; in fact it takes the place of a roof to a house. It likewise envelopes the branch, or branches, to which it fixes the nest, its sticky nature being here of great importance, and serves to bind the comb firmly to the plants. The cells are sometimes nearly circular, or deviate faintly from that form ; some of them are perfect hexagons. It is a most remarkable fact that in the same way though the entire nest-mass at times is round, or diverges little therefrom, often it too is hexagonal, and its six sides are as regular and the angles are as true as if they had been drawn with rule and compass (see Fig. 31). This is commonly the case with the larger nests ; the great ones reach a diameter of eleven or twelve inches. But near combs of the kind may be found quite small hexagonal specimens, showing that the insects have started with the idea of constructing on these lines, and having begun thus have adhered to the conception. The wasps hitherto considered are distinguished as manufacturers of paper, in general fine and thin and more or less brittle, the weakness of which they overcome by the superposition of a great number of leaves. There is a large class who while they make many kinds of papyraceous tissues, are noted for a feature in common the fabrication of a solid and tough paper, a veritable cardboard, com- v SOCIAL HOMES 187 posed of only one layer of material, at times very thick and resisting, at others slight and supple. Of this substance, after the manner of Vespa, the wasps usually build a papyraceous envelope or sac for the inclosure of their combs, and as in that genus,* the covering follows closely the direction of the plan of the cells. These nests attain an extraordinary degree of development and house a vast multitude of in- dividuals; even our nests of Vespa, the best suited of the previous category to support large populations, are extremely limited compared with some of the societies in question. The cause of the excessive in- crease is unknown, whether it be that these societies are formed on other bases, or that the climates that give them birth do not impose such stringent peri- odic destruction upon them as our winter season does upon those at home. Exposure to the more favourable climatic conditions, however, does not lead to great increment among Vespa and Polistes ; many of these companies abroad can hardly be said to be less scanty than ours, and it seems not unreasonable to conclude that a distinct difference lies at the root of the economy of the two classes. The genus Chartergus, one of the important groups of the cardboard makers, includes insects apparently similar which practise two strangely different forms of nidification. The nests of C. chartarius, the most common in collections, are of frequent occurrence in tropical America. Their card- board is white, gray, or of a buff colour, tending to yellow, very fine and of polished smoothness ; at the same time it is strong and so solid as to be imper- 188 ROMANCE OF THE INSECT WORLD CHAP. vious to the weather. It cannot be urged sufficiently, says Reaumur, that this kind of envelope is indeed of a veritable cardboard, as beautiful as any we know how to make. Reaumur once showed a piece to a cardboard manufacturer, and not the slightest sus- picion of its real nature was suggested to his mind. He turned it over and over, he examined it thoroughly by the touch, he tore it, and after all declared it to be made by one of his own profession, mentioning manufacturers at Orleans as the probable producers. The nests may be conical or cylindrical, they may be straight but more often are somewhat curved, some are almost globe-shaped, but these varieties are of little importance. The length of a well-sized nest is about a foot ; the largest yet discovered was in Ceylon, and measured the astonishing size of six feet. The edifice is pendulous on trees, and attached as it were to a suspensory ring, which embraces the branch, and is tightly impasted round it, or according to West- wood may be large compared with the latter's circum- ference, but it is probably a mistake to say that the nest ever swings freely as on a pivot. The interior consists of circular concave horizontal platforms of cells, their mouths turned downwards, each tier stretching right across like so many floors, and fastened along its entire edge to .the walls. Com- munication is effected by a central opening through the bottom, and through every tier. When the number of inhabitants becomes very great and a fresh series of cells is added, unlike the British wasps who add to their abodes by a preliminary increase of the envelope to admit of extension of the tiers, v SOCIAL HOMES 189 the Chartergus go to work on precisely the opposite plan, first forming new cells and covering them after- wards. Taking the bottom of the nest as starting- point they set cells over its exterior surface, being careful to extend the circumference by a row or two to augment the diameter in proportion to the length, so that the symmetry of the building may not be lost. The walls are then lengthened to include the fresh stage, and the end is closed with a new floor, in its turn to become the ceiling of the next tier of cells when further enlargement is desired. No trace of the addition is visible on the outside of the envelope, which would seem constructed at one stroke. The nest of C. apicalis is uneclipsed for grace of design ; it is one of the most wonderful examples of intelligent workmanship among insects. Exteriorly the form is a more or less fusiform* or spindle-shaped sac, terminating at its inferior extremity in a prolong- ation or narrow neck, which is open and constitutes the entrance. The sac surrounds and impastes the branches of trees, which piercing it almost from end to end act as its support. To the branches, in the interior a number of combs, one above the other much as in Vespa, are affixed ; as a rule the largest and straightest among them becomes the axis to the whole edifice. When the axes are multiplied, the regularity of disposition of the combs is destroyed ; numerous small cell-groups are commenced on the different branches, and at different levels, and do not unite to form perfect and complete tiers. Due to the shape of the spindle, the higher and lower combs are I9b ROMANCE OF THE INSECT WORLD CHAP. the smallest, the least mature, so to speak ; the middle ones are given ample room in the inclosure, and may be increased to great size. While the former are simply fixed against the axis and are more or less spreading, the larger tiers tend to surround it on all sides, so that the axis penetrates through them, though always somewhat excentrically. Communi- cation between the terraces is by spaces on the inner side of the covering, a simple sheet of paper, which, though slight, is solid and well gummed. Its surface is irregularly indented ; sometimes wrinkled transversely and circularly, and with great exactness. In some nests, on one or other of the faces, the points where the zones of paper and the wrinkles meet are very plainly shown, making the spindle look as though it were goffered. The branch that is accounted the true axis is never vertical; a slanting one is chosen as affording greater support. The neck projects to one side, and consequently it becomes necessary if the combs are to retain a horizontal position, that they cut the stem at an oblique angle. Notwithstanding the sustaining power of the axis, the tiers stand greatly in need of certain accessory though irregular props. Frequently they are united by pedicels, or columns, and are affixed to the interior of the covering by their edges by little scales or sheets of paper, leaving holes to enable the wasps to get from story to story. In this manner they are kept in their place, and the covering itself is rendered stronger by its numerous points of union with other substances. Another important means of support is gained by arched strips of paper v SOCIAL HOMES 191 adherent to the envelope, and more or less per- pendicular to it, which traverse the inner space and unite the borders of the combs, forming as it were vertical partitions upon the interior circumference of the sac. Enlargement of the nest is effected as in Vespa, but with greater difficulty, since the envelope is composed of a single leaf. Great cell-like papery protuberances are raised on its surface, and subse- quently the portions covered are eaten away by the builders from the inside. The pedicels, or columns, above mentioned, which unite the combs to each other, arise from careful preservation of parts of the old mantle, which naturally extend from the border of comb to comb. In the same way the vertical sheets of paper alluded to, which bind the combs to the new portion of the envelope, originate in the retention of the old leaf throughout its lines of meeting with the fresh superimposed coat ; and when the combs are extended to reach that coat, the strips form the par- titions described upon the circumference of the tiers adding much to their solidity. In spite of all these clever precautions the nest, owing to the feeble character of the envelope, is one of extreme fragility. The other kind of nest of Chartergus is con- structed on a straight and upright branch, having no lateral twigs. Its elegance cannot be sufficiently ad- mired. Composed of a few cells only, the combs are attached to the branch by means of petioles, or solid masses of wax, keeping the groups in a horizontal and parallel position. They stand one over the other, sometimes to the number of ten, separ- ated by considerable intervals, and so admirably 192 ROMANCE OF THE INSECT WORLD CHAP. upheld by the petioles that the aid of all pillars or columns is dispensed with. The envelope is a spindle of a single leaf of ligneous* paper, most artistic in appearance, being marked with transverse parallel tubings and goffered. The fibres of the tissue are arranged with surprising regularity; all the zones are united with consummate art, and meet in a long and plainly shown line ; the paper may be also variegated with longitudinal bands of different colours. The vase is firmly affixed to its axis at points slightly above and below the uppermost and lowermost combs, at no part is it in continuity with the combs, there is plenty of space between the two fabrics for the wasps to pass up and down within their home with ease. Taking advantage of the wholly lateral* position of the combs with respect to the axis, the wasps render their building less fragile than it would otherwise have been by placing the branch to one side of the spindle, and it saves time and trouble, without materially impairing the sup- port, to leave the wood exposed at the posterior surface of the papery mass. The opening is small and situated at the lower end (see Fig. 32). The pensile nest of Tatua morio bears great external resemblance to the ^pendulous cone-shaped nest of Chartergus chartarius, and is common in the same country. Two remarkably good specimens may be seen in our national collection. The outer walls are of a solid and durable paper, which is likewise thick, hard, smooth, and of a dark brown. Storms, however fierce, have little ill-effect on homes so well protected. Hardly less thick and strong are the various cell-floors, v SOCIAL HOMES 193 like the floors of the Chartergus circular in plan, but flat, and the union of each with the envelope is absolutely perfect. The entrance, however, is en- tirely lateral, and the insects gain admission to the different tiers by very eccentric* holes. A nest well in progress contains many combs. In one of the kind the lower chambers are likely to be incom- plete, since the floors are made before the cells are built. The wasps seem always to be in readiness for an emergency ; they build new stages ere they require them, and lay the foundations of future cells. The construction of the former is a long and toilsome business, but the latter are quickly formed, and eggs can be laid in cells that are just begun ; during the development of the larvae there is abundance of time to finish them. How many tiers are made before cells are attached to them, or whether cells are added as soon as the floors are completed are at present moot points. Though at the beginning of winter the nests are abandoned, they long resist the severity of the season ; whether the societies are dis- solved every year has not been ascertained. It is equally uncertain if colonies take possession of desert- ed nests or invariably build anew. Each comb may serve for one laying, or may be cleansed and put to further use. The genus Polybia is common in tropical America, in the Asiatic Archipelago it occurs more sparingly but is unknown in Europe. Some of the small homes, as those of P. palmarum and sedula, generally consist of a single comb of hexagonal cells on the surface of a leaf, and clothed with a ceiling of somewhat frail O 194 ROMANCE OF THE INSECT WORLD CHAP. paper, with an aperture towards the lower end. The insects have the sagacity to fix them to the underside of the leaf, so as to cause it to bend and form a natural roof. The building is also FIG. 33. View of exterior of nest of Myrapetra scutellaris. made to follow the shape of the supporting foliage, being round or oval under large broad leaves, long and slender under linear* leaves, and its size is always carefully limited, so that the leaf projects on all sides. When the comb is full it appears that a second stage SOCIAL HOMES 195 may be added upon the cover, and is completed with an envelope or ceiling. The regularity and perfection of construction is wonderful. P. liliacea makes a marvellous and often gigantic FIG. 34. View of interior of nest of Myrapetra, scutellaris. nest, four to five feet long, and of a diameter of one or two feet, containing thousands of cells. It is sus- pended from the branches of trees ; its covering is a rough cardboard, sometimes of a red-brown ; it is compressed at the top but widens out towards the O 2 196 ROMANCE OF THE INSECT WORLD CHAP. base. P. rejecta ofttimes forms a cone-shaped pend- ant nest, which when increased to great extent ends in a long symmetrical cylinder. Other nests are flask-shaped, the base being fastened to the tree ; some are almost globular. The species to whom the last belong, carrying out still farther the principle of enlargement adopted by CJiartergus chartarius and Tatua, build by placing cells not merely upon the outer surface of the layer of cardboard which at the moment constitutes the bottom of the nest, the entire outer wall is covered with cells, when the fresh tier is closed in with a new envelope. Thus a fairly large nest is composed of a whole series of concentric combs, forming hollow spheres set one within the other, not unlike the well-known ivory puzzle balls of the Chinese, the papery ceiling of each comb having been originally the outer wall of the nest. It follows from this arrangement that the direction of the cells is not uniform, as is generally the case with social Hymenoptera. They are neither all placed vertically with their mouths downwards, like those of most wasps, nor are they horizontal, as made by the bee. On the contrary, their bases all point towards the centre of the nest, and all their mouths radiate outwards. The various comb-tiers are generally remarkably close, and pierced with holes for com- munication. Very extraordinary are some of the nests be- longing to this genus in the collection of the British Museum the works of Myrapetra scutellaris (see Fig. 33), a mere fanciful title. These huge erec- tions are from Central America, and the native authori- v SOCIAL HOMES 197 ties say of one that it is not composed of wood fibres, but of the dung of the Capincha, one of the aquatic cavies of the region. One's attention is instantly attracted to the fairly conical knobs or tubercles* with which the surface is thickly beset, of various size, and most pointed where they are least exposed. Their disposition is in horizontal zones, seeming to corre- spond more or less with the comb-tiers. While at the top of the nest they are comparatively few, gradually the numbers increase towards the lower end, and on the bottom they are so numerous that one's finger can scarcely be laid between them. Like the envelope they are made up of several papery layers so closely blended as to be hardly distinguishable, forming a sub- stance astonishingly thick, hard, and firm, in colour of a dull dark brown, and of very coarse texture. Of what use they are it is difficult to decide ; they may be simply freaks of nature. Although their tips are not acute, they may defend the abode against the attacks of tigers, jaguars, kuguars, and other mammalia partial to honey and the grubs of the hive. The nest always hangs low, seldom more than three or four feet from the ground, and protection would appear much needed. It seems hardly possible to deny that they are for the double purpose of concealing and of sheltering the entrances, which are invisible when the nest is looked at from above. Examination reveals them beneath a row of the projections, which overhang them and keep off* the rains like the eaves of a house ; the passages are also intricately twisted, so as to prevent the ingress of moths or other enemies of any size. It 198 ROMANCE OF THE INSECT WORLD CHAP. is strange that the inferior surface of the nest is pro- vided with tubercles, a circumstance that must put the insects to the trouble of gnawing them away each time they add a stage. Probably the same material is again employed in establishing fresh cells, and in building the new platform. A longitudinal section shows the peculiar disposi- tion of the combs. Just as in the spherical nests of Polybia, the highest ones are perfect, or almost perfect, spheres; but this method of construction is soon found to be too laborious. A nearly globular mass of the brown paper-like substance exists at the top, the nucleus so to speak. The first combs closely surround this, so that they form the best parts of hollow spheres, then come great arcs of circles, followed in regular order by other tiers, their rotundity becoming gradually reduced until the curve of the lower ones is extremely shallow, exactly like the tiers of Tatua, except that they exhibit a trifling convexity on their lower surfaces. They are carried to the common wall, and thereto affixed, small spaces being left open here and *here between their edges and the envelope. The solid wall at the top is of great thickness (see Fig. 34)- In the nest in the British Museum already described, a quantity of brownish-red honey was found in the upper combs, but hard and dry. Even so long ago as the beginning of the century, Azara, a Spanish officer, who was sent out by his government to Paraguay to make certain investigations in that country, mentions that a South American wasp which he calls Chiguana has the strange habit of hoarding v SOCIAL HOMES 199 honey. The Chiguana of Azara, it would seem, is identical with Polybia scutellaris. At the time of publication Azara's statement was not believed, so opposed was the habit that he claimed for this insect to the known actions of wasps. He and his men ate from the Chiguana's store, and it proved deleterious. St. Hilaire, a subsequent traveller, speaks of two South American honey-wasps. The honey of one was white and innocuous, that qf the other was reddish- brown and poisonous. The good honey was in an oval light-coloured nest, of thin papery material, totally different from the paper of Myrapetra, and was observed by Hilaire on a small bush near Uruguay, at a distance of only about a foot from the ground. This wasp has been described as Lecheguana. Probably under the term Lecheguana, or Chiguana as Azara has it, the inhabitants of America confound many wasps of similar kinds, and it is rather a generic title for all honey wasps than for one species in particular. That honey is contained in these nests there can be no question ; the fact is proved beyond doubt by those in the British Museum. At the same time it is evident that the papery material is extremely ill- suited for the retention of the liquid, which has pene- trated and dropped from layer to layer of comb and materially damaged the cells. A nest of P. scutellaris containing honey was presented to the Museum about thirty years ago. In no part of it were brood, nor did it appear to have been recently in use for the purpose of hatching. Can it be possible that it was a deserted nest, adopted by a society of wasps merely 200 ROMANCE OF THE INSECT WORLD CHAP. as a temporary receptacle, a magazine for booty ? Wasps are well known to plunder hives, and the honey may have been treasure stolen from the stores of some Melipona or Trigona bee. If Polybia are really makers of honey, it seems only reasonable to expect that their cells would be of a nature to contain it ; moreover, that the stock laid by would constitute food for the young as well as for the community at large. It must be admitted that the absence of brood may be explained by the suppo- sition that the collection is made in the off-breeding season, when the company would consist solely of adults ; and when the death or repose of natural life precludes the wasps from gathering food abroad, the honey would serve them in good stead. The idea has been started, but merits little credence, that a nest of this kind is a forsaken wasps' nest invaded by some species of Trigona bee. Wasps' cells are unadapted to the great pursuit of bees, besides being considerably too large for the proper accommodation of these bees' larvae. The Nectarinia are likewise believed to be collectors of honey. Their beautiful globular nests, of fine grey paper like the paper of Vespa, but made up of a single layer, are plentiful in the deep recesses of the Brazilian and Mexican forests, being suspended near the ground from the boughs of bushes, while long delicate leaves and branches are woven into their substance, and in many places are carried through it and project on the other side. As in the case of Myrapetra, they consist of series of tiers composed alternately of comb and cover, the v SOCIAL HOMES 201 last being the leafy envelope. The spheres are more perfect than those of Myrapetra, but they are not always literally concentric* circles, and in reality they are incomplete towards the summit of the nest. This irregularity is unavoidable, for if the combs were only united at the top they could not be kept fixed firmly in their relative positions ; no pillars of union between them exist, as in Vespa. Nature sub- stitutes an excellent contrivance, which is at once a means of communication and a prop to the edifice. A veritable flight of stairs extends throughout the nest from the centre to the lower surface. The Nectarines, like other cardboard wasps, pierce holes through their successive stages as a means of traffic ; the combs being of immense breadth, the holes are numerous to save time and fatigue in gaining the exits, and the overcrowding of the passages that would otherwise result in the populous communities. But these routes are not deemed adequate for comfort and conveni- ence. To the underside of the great orifice with which each comb-tier is perforated, material is added, and prolonged obliquely downwards, so as to meet the platform of the comb lower. Tier after tier, from the top to the bottom of the nest, bears the same arrangement ; the hole in each tier is situated below that of its immediate predecessor. It will be per- ceived that the wasps in descending or ascending by these stairs and through these holes, pass in spiral* fashion from the centre to the circumference of the nest. The envelope itself is penetrated with a hole, and the ladder leads out into the open air. These 202 ROMANCE OF THE INSECT WORLD CH. v communicating sheets have other uses. Determined to make the most of everything, the industrious wasps cover the undersides of the papery plates with cells. They are therefore comb-ceilings, as well as staircases and pillars. Without going into details, the domain may be said to be enlarged by an extra sphere of cells upon the outside of the envelope and a fresh coat of paper. If the outer surface of a nest were covered with cells it would hold some thousands. Since the interior is made up of numerous similar surfaces, little smaller, one can hardly compute the sum total of inhabitants possible to be contained in such a city. Of all the kinds of wasps' nests, this of the Nectarines is the best for holding a large community. Due to its sphericity, the cells find room with the least expendi- ture of material. And while it can exceed others in cell capacity, and consequently in population, in actual volume it is far less cumbersome than other great nests. CHAPTER VI DEFENCES OF INSECTS, OR PROTECTION AS DERIVED FROM COLOUR Need of insects of means of defence Adaptation of their exter- nal colouring to conditions of life Protective Resemblances herein find explanation of first and most widespread use of colour among animals Principle of adaptive colouring solved by theory of natural selection Commonness of general harmony between colouring of insects and tints of nature Imitative tints of undersides of wings of butterflies Special Protective Resemblance 'stick-caterpillars 'and others leaf-butterflies British and European moths among Orthoptera tropical " walking-leaf" and " walking- stick " insects other insects and spiders Alluring colour- ing Resemblance of Mantises and spiders to flowers to excreta of birds Changes of colour corresponding to changes of environment Di- and Polymorphism their value meaning obscure Variable Protective Resemblance in pupae in larvae in colours of cocoons in perfect insects Variable Protective Resemblance and the origin of colour Power of adjustment of colour is adaptive, and is produced and maintained by natural selection. IT is unnecessary to enlarge upon an insect's need of means of defence. Obviously no creature could be more open to attack, and added to its peculiarly defenceless condition on all hands innumerable 204 ROMANCE OF THE INSECT WORLD CHAP. enemies wage continual war, many of whom derive their whole sustenance from insects. Nor are these tribes at peace with their own kind, but ever live in a state of internecine broil, the strong often preying on the weak and the cunning upon those of simpler wit. An insect is like a country of diminutive size, and apparently almost wanting in natural safeguards. No seas of unrivalled swiftness of motion roll round it and shield it from the depredations of foes ; no mountain barriers of strength enable it to withstand them. But our insect world is not without resource. Though small, its inhabitants are in multitude infinite ; and though from their nature seldom able to flee or to fight, on them are bestowed different modes of resist- ance to fate to save the race from extirpation. Among biological phenomena of great interest, the principle of disguise has long been known to exist in most classes of the animal kingdom. In other, per- haps plainer, words, their external colouring is adapted to their conditions of life. The resemblances are of different kinds; the most usual are cases of simple concealment. The animal in form as in colour imitates or simulates, more or less exactly, the ap- pearance of some object in its environment which is of no interest to its enemies, and thus passes un- detected ; or it harmonises in a general way with its surroundings, and so succeeds in eluding attention. In these instances the object imitated is invariably inanimate or part of a vegetable structure. The analo- gies go by the name of " protective resemblances." It does not seem possible for an insect to be more simply and admirably defended than by this system. vi DEFENCES OF INSECTS 205 More or less complete, concealment is useful to many animals, but to insects it is absolutely essential, and accordingly in insects adaptation to environment is most fully and markedly developed. In the animal world the members eat as they are eaten. To those that live upon others, and to whom activity and energy are denied, compensation in the boon of colour is also important colour such as may best serve the possessor to avoid alarming its prey, either by its presence or its approach. That in this explanation is learned what is the first and most widespread use of colour among animals seems corroborated by the fact, that protective resemblance is apparently possessed by insects in proportion to their sluggish movements or absence of other means of defence. This principle of adaptive colouring, though early recognised, found no intelligible exposition until the year 1859, when it met with perfect satisfying solution in Darwin's theory of natural selection, by which he explains how it was that evolution took place. Formerly among a certain section of the community the problem was referred to an originally created specific peculiarity, or the adaptation was understood to be due to the direct action of climate, food, or soil. But while the former interpretation puts an effectual bar to reasonable inquiry, since we cannot get beyond the fact of the adaptation, the second was found to be far from adequate to cope with all the varied phases of this strange phenomenon, and was controverted by some well-known facts. The gradually increasing change of disguised species, from a general harmony with surroundings to precise imitation of particular 206 ROMANCE OF THE INSECT WORLD CHAP. objects, is rather to be accounted for by the laws of a struggle for existence and survival of the fittest, while the elements permitting the birth and progress of the resemblance exist in the individual variability of the species, a variability that is hereditary. The commonness of the occurrence of a general resemblance or harmony of colouring between insects and the prevailing tints of nature, a similarity in general artistic effect, is hardly conceived by those unaccustomed to watch or speculate upon such things as these. In the different tribes, in the most adverse orders, this kind of protection abounds, affording its several possessors greater or less degree of invisibility to the prying eyes of antagonists, or the fear-fraught glance of the wished-for prey. In the tropics the colours of thousands of species, though perhaps brilliant and far from being alike, blend completely with the aspect of the spots where the insects habitually repose. At a few feet distant the surface and the insect may be absolutely indistinguish- able. It is one thing to see an insect by itself in a collector's cabinet, quite another matter to witness it in the state in which it ordinarily exists. Seen apart from its surroundings it may appear bright, and not adapted to escape observation ; in its everyday haunts, probably, that very brilliancy enhances its conceal- ment. The truth is we fail adequately to appreciate the tones of inanimate nature. We make little or no allowance for the infinite complications wrought by the ceaselessly changing play of light and shade upon colours which in themselves are far from uniform. A gaudy insect with numerous hues, if viewed in con- VI DEFENCES OF INSECTS 207 nection with its surroundings, or at a distance, may match neighbouring objects, and be lost as it were, or at least may obtrude itself less than if uni-coloured, or FIG. 35. A "Stick-caterpillar" (Ennomos tiliaria), which in colour, form, and attitude closely resembles a twig of a tree upon which it lives. adorned with tints more feebly contrasted. For this reason many tropical insects that take diurnal rest clinging to the bark of dead or fallen trees are not wholly brown ; the brown is delicately mottled with 208 ROMANCE OF THE INSECT WORLD CHAP. gray, the disposition of the two colours being sym- metrical and in endless variety of design. Nearer home, to take a familiar example, the large and com- mon caterpillar of the Privet Hawk Moth {Sphinx ligustri) is in reality striking in its green dress and purple stripes. But although it looks so conspicuous it harmonises remarkably well with its food-plant, and is sometimes troublesome to find. The purple, a dangerous introduction of colour one might be led to suppose, tends to neutralise the vivid effect of the extensive green area. However, deception of assailants or assistance in capture is often obtained by the reproduction with great exactness of the colour of the soil, or the vegetation inhabited by the insects. Of this mode of defence the beetle family offers no dearth of illus- tration. Among Cicindela, C. campestris frequents grassy slopes and is green ; C. maritima is found only on sandy shores by the sea, and is of a pale brownish yellow. Dr. Wallace discovered many of these insects in the Malay Isles invariably in harmony with their place of abode. C. gloriosa, of a velvety- green, was always taken on wet mossy stones in the bed of some mountain stream, the brown C. heros chiefly on dead leaves in the forest paths. The wet mud of salt marshes alone furnished a glossy-olive species, so closely corresponding to the colour of the mud that it was only distinguished, when the sun shone, by its shadow ! Where the beach was coralline and nearly white, Wallace saw a pale Cicindela ; where it became volcanic and black, a dark species of the same genus presented itself. A vi DEFENCES QF INSECTS 209 small weevil mercilessly persecuted by ground-beetles abounds in pits of a loamy soil, of the same colour precisely with itself, undoubtedly facilitating the escape of many from their foe. A scarce British weevil, by its grey colour spotted with black, is an equally good counterpart of the locality where it generally seems to roam, which consists of white sand mixed with black earth. In some cases a species confine themselves entirely to one species of tree, whose bark they simulate in colour and rugosity. They are excessively abundant, and surely it cannot be considered exaggerated to regard the protection derived from the resemblance as a factor, and no small one, in the flourishing condition of the race. Numbers of our weevils and other beetles when alarmed drop off the leaves on which they are sitting, at the same time rolling themselves into little lumps or balls. It is useless to look for them on the ground, where they lie motionless amid stones and earth-pellets, the appearance of which they simulate exactly. The fact is well known that however gay the upper surfaces of the wings of butterflies may be, the undersides are nearly always sober, often very dull and obscure, and in some instances have been observed to be like the surfaces whereon the insects customarily rest. This arrangement of colour is eminently'pro- tective, because during prolonged repose a butterfly takes care to hold its wings raised perpendicularly over the back, effectually to conceal its lovely but treacherous possession. Moths usually have their P 210 ROMANCE OF THE INSECT WORLD CHAP. chief colour on the hind wings, the fore ones are dowdy and often imita- tive in tint, and generally cover the lower pair when the insects are not in flight. Probably a thorough exami- nation of the habits of our butterflies would reveal their under surfaces to be much more frequently imitative than at present we believe to be the case. The concealment afforded by this means is effective, judging by the total disappearance of common FIG. 36. The cater- _ . -11 ,1 1171-1 pillar of Early Thom butterflies m bad weather. While Moth (Selenia illu- 1111 , naria), showing sup- some take shelter by creeping into porting thread of silk ; ,1-1 from Trans. Entom. nooks and corners among thick-set leaves, others cling freely exposed to surfaces that blend harmoniously with their own tints. To pass on to the more specialised forms of protective resemblance, not confined to colour, but which extend to outline and shape, and deal with the attitudes of the insects. As com- bining all these several features, no better instance could be found than that offered by the caterpillars of the Geometrae moths, "stick-cater- pillars," or surveyors, or loopers, as they are popularly called. For hours FIG. 37. Appearance of together these larvae will sit motion- the larva of Brimstone & Moth (Rumia crat#- j ess projecting at an angle more gata) when seated > Jr J among the twigs of its j ess acu t e from the bushes on commonest food-plant; from Trans. Entom. wri } cri they f e ed looking for all OCt * VI DEFENCES OF INSECTS 211 the world like the plant's own branches. The caterpillar is long, slender, and cylindrical, it holds itself stiff and immovable, so as to hide as far as may be the separations of the segments, and its free end where it terminates in the head one imagines to be the bud at the end of a twig. Little humps or tubercles likewise frequently exhibited on the body pass readily for additional buds or irregularities of the bark, and tend greatly to in- crease the resemblance. The likeness is promoted by the peculiar disposition of the legs. While the majority of larvae have five pairs of claspers, or legs persistent only in the caterpillar state, Geometrae possess but two pairs attached to their anal extremity. With them the caterpillar firmly grasps the stem, rendering them very inconspicuous, and to preclude the appearance of any limbs, the pairs of true legs immediately behind the head in many cases are applied closely to the body. The twig-like attitude is abandoned solely for feeding, which as a rule takes place in the evening or at night (see Fig. 35). On the face of it, this posture seems one impossible to be borne. No creature fashioned horizontally with the surface would be capable of erecting itself at an acute angle with its support, and of continuing to keep the P 2 FIG. 38. The hind part of the larva of Brimstone Moth \Rumia. cratagata)) seen from the right, showing the claspers and the fleshy projections which tend to fill up the furrow be- tween the larva and the stem ; from Trans. Entoiii. Soc. 212 ROMANCE OF THE INSECT WORLD CHAP. position for any lengthened period. Unaided, the caterpillar does not make the attempt. Fatigue is obviated by spinning a thread of silk, which is fastened at one end to the stem, the other end remains attached to the head of the insect (see Fig. 36). That there is con- siderable tension upon the brace may be seen by cutting it, when the larva falls back with a sudden jerk. In some cases the caterpillar is enabled to endure the strain by holding a leaf or twig with one of its pairs of articulated* legs. Many points of detail concur to promote this de- ception of Geometrae. The head is modified from its normal shape into one extremely suggestive of the top of a twig, or some vegetable growth, or at least to convey no hint of its real caterpillar nature. Com- monly it is notched, a plan forming a very natural end to the apparent twig. In the caterpillar of the Small Emerald Moth the segment behind the head is humped as well, while the latter is retracted, so that four blunt projections are produced, carrying out yet more admirably the resemblance to a twig. Similar unevennesses are obtained by the head and first body- rings being bent backwards (see Fig. 36). It might be supposed that the claspers by which the stem is held would excite attention and betray the insects. They however partially surround the branch, and appear to grow out of it (see Figs. 37 and 38). Lest the intervening space between the front and hind pairs should reveal the fraud, the underside of the larva is somewhat flattened, so that it lies in contact with a small portion of the round stem, On either hand the furrow is decreased, in vi DEFENCES OF INSECTS 213 some species at any rate, by the presence of fleshy pro- tuberances (see Fig. 38). The colour of the larvae is FIG. 39. Leaf-Butterfly in flight and in repose ; from Wallace. usually obscure, in general agreement with that of the bark of a tree ; sometimes the various tints of a stem 2i4 ROMANCE OF THE INSECT WORLD CHAP. are reproduced with marvellous fidelity. The Geometrae are a widespread and numerous tribe, divided into an immense number of species there are between two and three hundred in this country alone, a result that has been brought about, doubtless, by their acquisition of a form and attitude so well suited for purposes of concealment, admitting of their success in life's race, to the detriment of larvae with less perfected methods. In their wanderings Geometrae have come to feed upon a variety of food plants. These changes have in some cases necessitated corresponding modifications of attitude, of colour, or of form, in order to bring the larvae into harmony with their environments. Caterpillars of other groups secure protection by the imitation of surrounding vegetative objects, though perhaps hardly to such an astonishing degree. Some resemble the bark of thick branches, and repose against the bark, closely adhering to it. The furrow that they would make with the branch is obliterated by hairs, or by a row of fleshy projections, at least in all probability this is the use of these structures. The appearance of lichens* is also commonly simulated by larvae that ordinarily rest on lichen-covered bark. " Stick caterpillars " in the earlier portion of their career do not stand upon the branches, but upon the leaves of the plant on which they feed, where the twig-like attitude would be inappropriate. Some are green in colour, so that they correspond with the leaves ; in other cases the caterpillars are brown, as at later times, and the attitude is then often modified to avoid danger. Twisting itself into spiral or zigzag vi DEFENCES OF INSECTS 215 shape, the insect passes muster as a bit of dead and curled up leaf, or as the excreta of birds or snails. Imitation of the excrement of birds is however rare and exceptional. In mature Lepidoptera, the most wonderful and undoubted case of the higher form of protective resemblance is that of the Malayan Leaf-butterfly, Kallima paralekta, and its Indian ally K. inackis. The method of concealment has been described by Dr. Wallace, who was the first to observe it, in his Malay Archipelago, and elsewhere. The upper surfaces of the wings are showy, conspicuous, and large, with a broad rich orange band across the fore-wings on a deep bluish ground. Opposed to this brilliancy the under surfaces, though varying greatly, in every case are of sombre tint, of some shade of gray, or brown, or ochre, such as is common among dead or withered leaves. 'Mid leaves of the kind on a nearly upright twig the butterfly rests, and in this position with the wings tightly closed over the back, thus exhibiting their under surfaces, is in exact agreement with its surroundings, the irregular outline of the folded wings forming a direct and finished representation of a moderate sized leaf, shrivelled or withered in some stage of decay. The tip of the fore-wing is produced into a point, a common form of leaves in the tropics ; the hind-wings terminate in a short narrow tail, which touches the branch, and typifies a perfect leaf-stalk. From end to end along the whole length of the supposed leaf runs a distinct dark line, the seeming mid-rib ; from this on either side radiate oblique lines imitative of a leaf's lateral venation.* The butterfly 216 ROMANCE OF THE INSECT WORLD CHAP. disposes of the rest of its body so as to bear out the deception. In place of keeping its head and antennae in motion, a custom with butterflies, Kallima does not expose these parts, and draws them back out of sight between the bases of the wings. The middle pair of legs by which the insect clings to the branch, and keeps the "leaf" in due position, are slender and almost invisible among the twigs and fibres that .surround it (see Fig. 39). Dead or withered leaves are often attacked in different places by various kinds of minute fungi, and are pierced with holes by insect larvae. In conformity with their patterns, extraordinary to say, the undersides of the wings of the butterflies exhibit representations of blotches and mildew. In many cases they are irregularly covered with patches and spots, so closely resembling fungi found on dead leaves that it is almost impossible to believe the creatures in truth are not suffering from incursions of real fungi. Their semblance of a larva's hole is equally accurate and telling. The scales covering the wings are absent from a window-like naked spot on each fore -wing, which is therefore only clothed with the thin transparent wing membrane. When the butterfly raises its wings in the position of rest these spots come together, producing the effect of a hole, since the two membranes are almost of the trans- parency of glass. Colour, form, size, and habits have thus each their parts to play in this marvellous resemblance, and that it affords protection is shown by the abundance of in- dividuals that possess it. To the habits of the butter- VI DEFENCES OF INSECTS 217 fly is assigned not the least important role. Of what avail would be the disguise were the insect prone to settle upon a flower, or green leaf, or other inappro- priate surface, or to open its wings and display its attractive colouration. The Malayan species seems to be as wary during the brief pauses between the flights as during lengthened rest. Dr. Wallace has observed scores of K.paralekta in Sumatra, where they frequent FIG. 40. "A Walking Leaf" Insect ; from Belt. dry woods and thickets, and they were never seen to settle but on bushes or trees with dry or dead leaves. They settled, and, as if by magic, were lost. Search for them on these occasions was usually in vain, for while gazing intently at the very spot where one had 2i8 ROMANCE OF THE INSECT WORLD CHAP. disappeared it would suddenly dart out, and again vanish a few yards farther on. But the butterfly has been detected reposing, and its close assimilation with the surrounding leaves was then evident. The flight of Kallima is swift, a circumstance affording great assistance to the fraud. In a recent paper, Mr. S. B. J. Skertchly calls attention to the fact that leaf- mimickers of several genera and Kallima among them settle in a totally different manner from that of other butterflies. The latter when about to alight gradually slacken speed, but the leaf-butterflies ' fly rapidly along, as if late for an appointment, suddenly pitch, close their wings, and become leaves.' Keen observation would probably bring to light many cases of special protective resemblance among our British and European moths. Such as Agriopis aprilina, Acronycta psi, and many others which re- main by day on the sides of trunks of trees so exactly resemble the gray and green lichens that cover the bark as to be distinguished with difficulty. Bryophila and many Geometers are the very images of the mortar walls or the surfaces of stones that they frequent. Numerous gray and white Geometers which rest on the upper sides of leaves forcibly suggest the excreta of birds. The well-known Buff-tip Moth (Pygcem buce- pJiala] is admirably disguised by resembling a broken end of a decayed and lichen covered branch, the cylinder-like effect being obtained by the wings being carried round the body. The Lappet Moth is also very perfectly concealed by resembling an arid brown leaf, both in shape and colour. As seen in flight, the Yellow Underwing (Triph&na pronubd] might likewise vi DEFENCES OF INSECTS 219 be mistaken for a withering leaf tossed along by the wind. The Herald Moth (Gonoptera libatrix], one of the most beautiful of these imitations, represents a red-brown leaf having succumbed to a certain amount of white fungoid growth. Lest its bright eyes* should expose the deception, a tuft of hair falls over them and conceals them during rest. The delicate veil is easily raised as the insect takes to flight. It has been remarked that a striking harmony exists between the colours of the British autumn and winter moths and those that prevail in the respective seasons. In autumn vegetation as a whole dons a sober brown and yellow livery, and out of fifty-two species then on the wing, forty-two are of correspond- FIG. 41. A " Walking-Stick," or Moss Insect ; from Belt. ing shades. Gray and silver are the characteristic tones of nature's winter garb, and accordingly these tints predominate in the winter moths. The Lcpidoptera apart, the whole order of Orthop- tcra (grasshoppers, locusts, crickets, &c.) will be found to be signally happy in respect of the possession of this protection, every grade in resemblance being repre- 220 ROMANCE OF THE INSECT WORLD CHAP, sented, from a general harmony with the vegetation FIG. 42. Imitation of a Flower by a Mantis (Hymenopus bicoinis) in active pupa stage ; after Wallace. or soil commonly surrounding them up to the most vi DEFENCES OF INSECTS 221 striking examples of special imitation of definite objects. Many of the tropical Locustidae and Phas- midae, in the colour, texture, and veining of their elytra, are like green leaves ; others represent leaves in various states of decay. In none the dissimulation is carried to greater extent than in the wonderful genus Phyllium, " the walking-leaf" (see Fig. 40). Not only have the wings assumed the appearance of leaves, the thorax and legs have been equally adap- tive, and have become flat, expanded and leaf-like, to the elimination of their ordinary forms. When the insect is resting among its food-plant often the closest scrutiny fails to distinguish the difference between the animal and the vegetable. Many of the species of Phasmidae the family to which this insect belongs, the " spectres " or " praying insects " as they are popularly called are known as " walking-sticks," from their singular resemblance to twigs and branches. Their colouring, form, rugosity, and arrangement of the head and legs are all in accurate accord with the appearance of dead sticks ; in a word, when " walking- sticks " are seen stationary it seems scarcely credible that an imposture is being played. In Brazil, and elsewhere, some are no less than eight inches and. even a foot long and of the thickness of one's finger. They hang about shrubs in forests, and have the extraordinary habit of holding out their limbs unsym- metrically, the better to typify a branch with lateral spray (see Fig. 41). In a case recorded by Dr. Wallace the trickery does not end here. A "walking-stick" (Ceraxylus laceratus) obtained in Borneo exactly resembles a 222 ROMANCE OF THE INSECT WORLD CHAP. stick grown over by a creeping moss or junger- mannia,* an appearance due to certain foliaceous excrescences or irregularities, of a clear olive-green colour. So absolutely identical were the counterfeit and the reality, the native Dyak who brought in the insect maintained it was grown over with moss, although alive, and it was only after minute ex- amination that Dr. Wallace could convince him- self that the fact was not so. The change of character is pronounced. In Darwin's opinion there is nothing improbable in this insect having varied in the irregularities on its surface, and in these having become green. Importance is attached to the details of form and colour in the Beetle family. The small Buprestidse, for example, which generally rest on the mid-ribs of leaves, closely resemble the excrement of birds. Chlamys pihila is undistinguishable from the dung of caterpillars. The genus Chlamys furnishes another illustration of this method of concealment and pro- tection in a brilliant and beautiful beetle, said to suggest some kinds of fruit by the inequalities of its red-coloured surface. Some of the Cassidae, from their shape and colour, sparkle like dew-drops upon leaves. From the Heteroptera we get a representation of a withered and crumpled leaf, with the edges turned up and eaten away, as if by caterpillars. Some bugs simulate leaves in skeleton, when the parenchymatous* portion has disappeared and the network alone is left. Spiders are often protectively coloured, and imitate the lichen on tree-trunks (as Philodromus). They are eagerly sought by insectivorous* animals, so vi DEFENCES OF INSECTS 223 that the resemblance is doubtless to their immense advantage. In many cases, however, their adaptation is chiefly aggressive, enabling the spiders to capture their prey. Turning to Aggressive Resemblances, certain car- nivorous insects, as the Mantidce, are well concealed by harmonising with their surroundings. This, though to a large extent protective, also assists them to creep upon, or to lie in wait for, their prey. Aggressive Resemblance becomes of more than ordinary interest when it not only screens an insect from its prey, when it simulates some object pleasing or attractive to the latter, and so induces its approach it acts as a lure, and entices the unsuspecting victim into the spot for convenient capture, into the very jaws of death. Species of mantis, both from India and Africa, are endowed with this dangerous fascination. They have all the appearance of fine flowers, things of special value to insects of vegetarian tastes. They draw near, and of course are greedily made away with by the seeming blossoms. Hymenopus bicornis, a mantis of great rarity, in- habiting India and Java, in active pupa is an inimitable representation of a flower. Colour, form, and attitude all conspire to produce the remarkable deception (see Fig. 42). These mantises may be white or pink. The thighs of the four posterior legs are expanded into broad pear-shaped plates, constituting the appa- rent petals, and when the species is seated they are spread out two on each side, while the fore-legs are tucked out of sight under the thorax. There need be not the slightest hesitation in stating that 224 ROMANCE OF THE INSECT WORLD CHAP. even butterflies are attracted, as insects to flowers, and the deceivers feed on the dupes allured. An equally interesting instance of this striking simu- lation is exhibited by another Indian mantis, Gongylus gongylodes (Linn.). It is, however, only the under surface of the animal that displays the resemblance. The leaf-like prothoracic * expansion, instead of being green, is of a clear pale lavender- violet colour, inclining to mauve, and acquiring a reddish tinge towards the margins, and with a black-brown blotch in the centre, representing 'the opening of a tube in the middle of a flower's corolla. The insect is addicted to hanging head downwards amongst a mass of green foliage, and remains motion- less, or occasionally sways about like a flower touched by a gentle breeze. With its fore-limbs banded violet and black, and drawn up in the centre of the corolla, it looks exactly like a papilionaceous * flower. The disguised limbs act as a decoy to insects, which fly directly into the sabre-like raptorial * arms of the simulator. 1 The resemblances of spiders to flowers are probably chiefly cases of the same offensive dis- guise, as opposed to purely defensive imitations. The bunches of blossom of the way-faring tree, Viburnum* have been observed to be occupied by spiders of a pale creamy white, the exact tint of the flowers, and their abdomen closely resembled the unopened buds of which there were many in each cyme not only in colour, but in size and shape. These spiders are by nature hunters and not web- 1 Proc, Entom. Soc., 1877, xlix, vi DEFENCES OF INSECTS 225 spinners, and the number and variety of insects that visited the blossoms were great. Somewhat later in the year similar, if not identical, kinds were seen on the wild guelder-rose, and on Orchis maculata. Many bushes of the mealy Viburnum were growing close by, but their blossoms were over. The spider on the guelder-rose had reddish-brown spots on the side of the abdomen, but not sufficiently distinct to interfere with the perfection of the disguise. But in the case of the one on Orchis maculata the spots on the sides of its abdomen were large, of a dark red-brown colour, and very sharply defined ; and when he stood in his usual position, with his head downwards, they very clearly resembled in size, shape, relative position, and at a yard's distance even in colour the dark purple pollinia * of the flowers. Though many of these spiders were present on Orchis maculata, not a single one could be dis- covered on the dwarf orchis (O. ustulata), which is much like maculata, but its pollinia are not dark. Mr. Nottidge suggests that as the season advances these spiders change colour, and each successive change specially adapts them for concealment on the blossom of some special plant. 1 Mr. Jenner Weir 2 has also seen these spiders (Thomisus citreus) station themselves in the centre of a composite * flower, with their legs expanded like its exterior rays, and some- times in the flowers of orchids, with their legs ex- panded horizontally. Apparently they are capable of destroying even the honey-bee, which he has found dead in their clutches. 1 Proc, Entom. Soc., 1878, xl., xli. 2 Loc. cit. Q 226 ROMANCE OF THE INSECT WORLD CHAP. Beautiful examples of Alluring Colouring occur in the resemblance of Mantidae to the excreta of birds. Flies are often attracted by such droppings, and the Mantidae take advantage of this fact to secure their prey. A similar instance was discovered by Mr. Forbes in Java, in a spider (Ornithoscatoides decipiens), whose imitation of a bird's dropping from a height on a leaf is carried out with minute detail colouring, form, and habits contributing to the success of the resemblance (see Fig. 43). This is one of the most remarkable instances of faithful assimilation of an animal to a vegetative or inanimate object, and affords a wonderful example of what is in the power of natural selection to accomplish. The principle of natural selection alone is sufficient to explain the case, for the acquisition of every new grade in the likeness would at once give the owner an advantage in the continual struggle for food. In the foregoing cases of protective resemblance the imitated objects are constant in their nature, and the disguising characters of the imitating species remain constant throughout the lifetime of each individual. As regards leaf-butterflies and others which resemble withered leaves, the constancy of the individual is no less perfect, but the imitated objects vary slightly in hues, calling forth a corresponding variability of colour among the copying species. There are a few examples where each insect under- goes a rapid change of colour once during its lifetime. It acquires a new habit, entailing change of environ- ment, and with the fresh surroundings relationship must be set up. Obviously this change of habit in vi DEFENCES OF INSECTS 227 the species is equivalent to a change of character in the imitated object. Among insects in this class may be mentioned the larva of Sphinx ligustri. When full-fed previous to pupation, it deserts its food- plant and descends to the ground to find a suitable burying-place, where its bright green coat would be conspicuous and rife with danger. Accordingly the caterpillars lose their original colour, and become brown, bringing them into consonance with their new surroundings. Professor Meldola was the first to perceive the true meaning of this change. An in- stance is afforded by Geometrse of exactly the op- posite alteration at a corresponding period. In its young days the larva (Ennomos angularia) is a brown " stick-caterpillar," and receives special protection from its resemblance to twigs. Eventually it forms a cocoon of green leaves loosely put together, so that its body is plainly visible through the leafy screen But at the same time its brown colour disappears, and its surface becomes green, due to its green blood, which is visible through the transparent skin. The tendency in caterpillars is to become dull in colour on the approach of pupation, and these inci- dental changes, in all probability, have constituted the accidental resemblance to the soil, the initial start as it were, from which the definite alteration has been developed by natural selection.* That the change must sometimes prove disastrous to the individual is unquestionable. If at this crisis of life a caterpillar of the Privet Hawk Moth were to descend upon turf, or ground covered with other green vegetation, it would still turn brown ; although its green dress would Q 2 228 ROMANCE OF THE INSECT WORLD CHAP. conceal it more effectively. But assuredly on the whole the change must be advantageous to the FIG. 43. A inosa, 153 Forms of animal life, more advanced, pro- duced by Old World than New, 164 Fossorial hymenoptera, 85 strange food of young, 85 Odynerus, homes of, 86 sand-wasps, 87 Frequency of moults of larva, 7 Freshly-formed pupa?, description of, 9 GAD FLIES, parasitism of, 37 Galleridae, caterpillars of, 42 Gall flies, or Cynipidae, their habits, 90 Gall makers other than Cynipidae, 95 Galls, 89, 91 oak especially subject to, 89, 91 cherry, 91 spangle, 92 currant, 92 Robin Redbreast's pincushion, 92 of commerce, 93 Dead Sea fruits, 94 oak apples, 91 Garden Whites, see Pieridae Geometrae, larvae of, special protective resemblance of, 210 Goat moth caterpillar, increase of, 7 a burrower into wood, 97 Gosse, Mr., on trapdoor spiders, 112 Grasshopper, crop in, 22 mimicry of, 268 metamorphoses of, 3 Great development of thorax, when it occurs, 1 8 Gregarious habit of caterpillars, itself a "warning," 248 Gregarious sawflies, emission of offensive fluids, 244 Guardians of plants, ants as, 149 H HABITATIONS, of solitary larvae, 95 simplest form of, 95 of solitary insects for young, 73, 89 of solitary architects for own use, 72, 95 Jo? Hairs, irritating, of caterpillars, 245 Halictus, homes of, 74 Harmony of colouring between insects and tints of nature, commonness of, 206 Harvesting ants, in East, 55 ; record in Mishna of, 55 of Europe, 55, 145; nests of, 145; domes wanting in nests, 145 ; prevention of germination of seeds by, 56 in America, 56, 135 ; disks of, 56, 135, 140 ; harvest fields of, 56, 137 Head of insects, made up of segments, number of, 19 appendages of, 19 Heliconidae, similarity to Danaidae, good results, 252 as models for mimicry, 255, 258 Heliconoid Danaidte, 252 INDEX 293 Hemiptera mimicking hymenoptera, 268 Hepialidae. caterpillars of, 96 Hermit homes, 71 Heteromorpha, the series so-called, 3 Hive bee, 73, 156, 162, 164, 267 Homes, hermit, 71 necessary to insects, 71 of spiders, English, 109, 115 social, 118 Homomorpha, the series so-called, 3 Honey ant, 51, 53, 144 the rotunds, 51 analogy between economy of and that of bee in storage of food, 51 Dr. McCook on, 53 Sir John Lubbock on, 53 nests of, 144 habits of, 52, 144 Honey bees in East, 162 Honey wasps, 198, 200 St. Hilaire on, 199 Hornet's nest, compared with wasp's, 178 favourite spots for, 178 frequent absence of envelope, 178 entrances to envelope, use, 179 sometimes great size of, 180 materials for manufacture of envelope, 1 80 Reaumur on, 179 Hornet Clear-wing, mimicry of, 265 House-builder moth, 103 Huber, on ash-coloured ant, 132 on F. brnnnea, 129 Humble bees, state of, at first emergence from cells, 13 in North America, 163 as models for mimicry, 265, 273 Hydrocampidae, larvae of, 107 Hymenoptera, fossorial, 85 mimicked by lepidoptera, 263 mimicked by diptera, 266, 272 mimicked by coleoptera, 267 mimicked by orthpptera, 267 mimicked by hemiptera, 268 dimorphism among females, 229, 231 as models for mimicry, 265, 266, 267 268, 272, 273 sting of, a means of defence, 246 warning colours of, 247 offensiveness of, 244 Hyinenopus bicornis, 223 Ic ARIAS, description of nests, 183 problems of economy of societies of, 184 Imago state, assumption of, 12 Imitation of surroundings, manoeuvre to effect, 209 Incomplete metamorphoses, examples of, 3 I ncrease of larva, reasons for, 7 Individual differences, Darwin on, 231 Insect architecture, diversity of method, 118 Insect architecture, its beauty, 118 size as coanpared with makers, 118 propriety of use of word, 119 Insect parasites upon insects, mighty business of, 40 Insects, means of procuring food, 65 which mimic vertebrates, 270, 271 Instruments of nutrition of insects, 58 for biting, 59 for sucking, 59 reduction to one design, 59 Internal organs, modification of, during metamorphoses, 21 Intimate connection of ants, with cocci, 45, . I5 with beetles, 45 KALLIMA, protective resemblance of, 215 LADY-BIRDS, as models for mimicry, 268 eject disagreeable fluids, 245 Lamia ainputator, larvae of, 99 Larva, produced alive, 3 meaning of term, 5 English terms for, 5 change to pupa, 8 stage, especially liable to parasites, reason of, 40 cold, damp, effects on, 8 Larva of Puss Moth, mimicry of, 271 elaborate means of defence of, 272 Larva of Tabby, its partiality for grease, 41 adaptation of structures for mode life, 4 1 evolved from ancestors living different lives, 41 Larvae, solitary habitations of, 95 Larvae of Coleoptera, burrowers into wood, 98 Scarabaeidoe, 98 Scolytiis destructor, 98 Calandra, 99 Titan-its gigantens, 99 Lamia amputator, 99 Larvae of flies, destitute of legs, 16 Larvae of Geometrae as instances of special protective resemblance, 210 Larvae, leaf-mining, 102 Larvse of Lepidoptera, burrowers into wood, 95 of Sesia apiformis, 95 Hepialidae, 96 Goat moth caterpillar, 97 Larval life, length of, 8 Leaf-butterflies, 215 _ _ Leaf-cutting propensities of ant, Sauba, 134 Leaf-cutting bees, 82 Megachile, curious homes for young, 82 ; account of genus, 82 ; method of obtaining building material, 83 294 INDEX Leaf-cutting bees M. centuncularis 82 the upholsterer, 84 exotic species, 84 Leaf-insects, 221 Leaf-rolling caterpillars, 101, 102 Leaf-sewing caterpillars, 102 Lecheguana, 199 Legs, larva? of flies destitute of, 16 difference between true and false, 17 Length, of larval life, 8 of life of insects, 14 Lepidoptera, mimicry in, 254, 258 protective resemblance to bark and lichen, 213, 214, 218 offensiveness of, 244, 245 protective pupal covering of, 10 high adaptation to floral diet. 62 mimicking hymenoptera, 265 Lepidopterous eggs attacked by parasites, 40 Leptalis, mimicry in, 259 Life history of insects, character of, 2 story of, 5 often an ephemeral span, 14 Linnaeus, on adoption of term larva, 5 Locomotion, acquisition of power of, at end of pupal period, 12 Locusts, voyages of, 29 metamorphoses of, 3 mimicking a tiger-beetle, 268 Lubbock, Sir John, on ants as cattle breeders, 44 on honey ant of Australia, 53 Lycosa. piratica, 117 Lycosides, 113 M MANNER of adjustment of pupal colour, discarded theory, 233 Manoeuvre, to effect imitation of surround- _ ings, 209 Mantidse, aggressive resemblances in, 223, 226 aggressive mimicry of, 272 Mantis, resembling white ants, 272 Mantises, resemblance to flowers, 223 to excreta of birds, 226 Mason ants, 51, 119, 128 nest of F. brunnea, 129 building material, 129 Huber on, 129, 130 moisture necessary to, 130 work after dusk and during rain, 131 of New World, 51, 56, 135 Mason bees, social, 164 Mason bees, solitary, 79 Osmia and Chalicodoma, architecture of, 79 C. muraria, building operations, 79 occupation of old nests, 81 May-fly, pseudo-imago state of, 13 McCook, Dr., on honey ant, 53 on Occident ant of American plains, M3 Megachile, 82 Meldola, on photographic sensitiveness of chrysalides, 233 Prof., on the larva of S. ligustri, 227 Prof. , explanation of general similarity in groups of unpalatable butterflies, 2 5i on aggressive mimicry of ant-like spiders, 273 Meliponafasciculata, 164 Mehponae, domestication of, 166 supposed presence of several fertile females in colonies, 164 homes of, compared with hive, 164 restricted to New World, 166 Metamorphic stages, considered in detail, 3 changes, apparent suddenness of, 31 Metamorphoses of insects, i study of structures implicated in, 15 explanation of, 30 old ideas of, 14 modern theory, 14 is a progressive development, 15 Mimetic analogies among beetles, 265 Mimicry, a phase of protective resem- blance, 258 natural selection concerned alike in both phenomena, 258 the term, 257 true, confined to tropics, cause of, 274 frequency and perfection of, in insects, some reasons of, 274 as distinct from all warning appear- ances, 256 two supposed explanations of, 263 is produced by natural selection, 258, 262 ; conclusive argument in favour of theory, 262 Bates, Mr., on, 254 Mimicry of ants by spiders, 269, 272, 273 Mimicry of butterflies, American, 255, 258 Asiatic, 260 African, 260 Mimicry of coleoptera by orthoptera, 268 Mining bees, 74 Andrenidse, 74 Halictus, 74 Mishna, record of ants in, 55 Modification of internal organs during metamorphoses, 21 Mole cricket, home of, 107 Moths, British and European, special pro- tection of, 218 Moults of larvae, 6 frequency of, 7 Moults of lining of internal organs, 6 Mouth organs, as appendages of head, 19 Miiller, Fritz, explanation of resemblance of unpalatable butterflies, 251 upon a S. American Swallow-tail, 237 Mushroom growers, saiiba ants as, 135 Muslin moth, probable mimicry of, 260 Mygalida?, tunnels of, 109 Myrapctra scutellaris, 196 tuberculated covers of nest, 197 nest, formed of dung of Capincha, 197 INDEX 295 Myrctpetrct scutellaris longitudinal section through nest, 198 as a honey gatherer, 198 Myrmecophilous, or ants'-nest beetles, 45 Myrmica Kirbii, 151 NATURAL SELECTION, theory of, solves principle of adaptive colouring, 205 part played by, in association of bright colour with distasteful qualities, 247 and mimicry, 258, 262 Nectar of flowers, specially attractive to insects, 36, 62, 63 Nectarinia, admired globular nests of, 200 where found, 200 construction of nest, 200 their flight of stairs, 201 method of enlargement of nest, 202 enormous cell-capacity of nest, 202 Need of insects of means of defence, 203 Nervous system, in insects, 23 design of, constant, 23 in vermiform larvae, 23 modification of, for perfect insects, 24 Nests, wasps', principles of enlargement, i7S Newport, on chitine, 20 on moulting of skin, 20 Nurses, need of, by young of social hymenoptera, 47 Nursing bees, 48 Nutrition, instruments of, 58 Nymph, term for pupa stage, 10 OAK especially liable to galls, 89, 91 Oak-apples, 91 Occident ant of American plains, where found, 140 architecture, 140 "clearing," reason for, 140 path-ways absent, why, 141 roofing of mound, entrances, 142 interior of nest, 143 habits different from Agriculturist, 140, 141, 142, 143 Dr. McCook on, 143 Odynerus, 86, 267 lEcophylla sinaragdina, 152 Old world, has produced more advanced forms of animal life than New, 164 Meliponae, absence of, in, 166 Orchids, epiphytal, 150 Orthoptera, offensiveness of, 244 mimicking coleoptera, 268 protective resemblance in, 219 mimicking hymenoptera, 267 metamorphoses of, 3 O.smia, homes in shrubs, 81 contrivances in snail-shells, under stones, 8 1 PAPILIOS, mimicry in African, 260 mimicry in South American, 259 mimicry in Asiatic, 260 as objects of mimicry, 260 Parasites, 37 insect pests, and vegetables, balance of life between, 41 a protection to pur crops, 40 upon insects, mighty business of, 40 adult insects subject to, 40 Parasitic bees, 49, 273 Parasitic hymenoptera, 38, 49, 273 habits of, 38 ; unvarying, 39 condition of insects attacked by, 38 their power to detect victim concealed from sight, 39 their power to gauge appetites of young, 39 eggs of insects attacked by, 40 Parasol ant, 134 Patterns, similarity of, for warning, 250 Peckham, Elizabeth, on mimicry of ants by spiders, 269 Pelopaeus, 88 Pensile nests, of Crematogaster, 151 of Formica elata, and Myrmica Kirbii, 151 vlCEcophylla smaragdina, 152 Period of quiescence, the death-like, n, 33 Photographic sensitiveness of chrysalides, Meldola on, 233 Phytophagous insects, how kept in check, 40 Pieridae, mimicking Heliconidae, 259 females more beautiful than males, 262 Polistes, description of, 180 system of nidification, 180 shape of nest, variable, 181 nest protected by varnish, position &c., 1 80, 181 problems of economy of societies of, 183, 184 Polistes aterrima, 182 Polybia, nests of, 193 P. palmar urn^ and seifiela, 193 P. liliacea, 195 P. rejecta, 196 principle of enlargement of nests, 194, . J 9 6 . direction of cells, 196 communication in nests, 196 Possibility of enlargement in all honey- feeding ants, 54 Poulton, Mr., experiments on variable protective resemblance, 233 ; deter- mination of period of susceptibility, 234 ; of organ or part susceptible, 2 35 on insects which mimic vertebrates 271 Power of locomotion, acquisition of, at end of pupal period, 12 2 9 6 INDEX Predaceous insects that resemble their prey, 272, 273 or a form to which their prey is in- different, 273 Privet Hawk Moth, brilliant colour of, enhances concealment, 208 change of colour of larva, 227 Problems of economy of societies, of Polishes, 183, 184 of Icarias, 184 Proboscis of butterflies, how formed, 60, 62 appendages of, 63 use of, 62, 63 position in rest, 63 various lengths, 64 ascent of fluid in, 64 Protection of insects by means other than protective colouring, 243 by nauseous properties, 244 by irritating hairs, and spines, 245, 246 by the sting, 246 hardness of substance, &c., 246 Protective mimicry, 254 in lepidoptera, 254, 258 by female butterflies only, 261 ; inter- pretation of phenomenon affords confirmation of theory that mimicry is produced by natural selection, 262 in British lepidoptera, 260 Protective pupal covering of Lepidoptera, 10 Protective resemblance, 204 herein find explanation of first and most widespread use of colour among animals, 205 in butterflies and moths, 209, 215, 218, . 2I 9 L in orthoptera, 219 in beetles, bugs, spiders, 208, 209, 222 specialised forms of, 210 distinguished from protective mimicry, 252, 256, 258 Providence of European ants, 55, 57, 146 Pseudo-imago, 13 Psithyrus, aggressive mimicry of, 273 Psychidae, building performances of, 103 Pupa, state of, various terms for, 10 meaning of term, 10 nature of condition in insects with complete metamorphoses, n, 33 length of period, n ; determining causes, 12 indications of approaching change, 12 change to imago, 13 Pupae, freshly-formed, description of, 9 shelters for, 8 butterflies, preparation for change to, 9 Puss Moth, mimicry of larva, 271 elaborate means of defence of larva, 272 QUIESCENCE, of the death-like period of, ", 33 RAFT spider, u6 Reaumur, experiments of, regarding de- velopment of chrysalis, 12 on hornet, 179 on Chartergus chartarius 188 Regionsof body of insects, how formed, 15 Remarkable instance of foresight of ants, Resemblance, between warning colours and patterns, determining causes of repetition, 249, 250 of spiders to ants, explanation of, 270, 272, 273 of mantis to white ants, explanation, 272 Respiration, increase of, at change to imago, 12 of insects in water, 27, 28 Respiratory system in insects, 26 Restriction, of larger herbivorous animals to certain parts of plants, 35 of one species of insect to one species of tree for resemblance sake, 209 ; usefulness of, 209 usual, of insects to vegetable or animal diet, 45 ; exceptions, 45 Retarded birth of insects, 3 Robin-Redbreast's pincushion, 92 SALIVARY GLANDS, 23 in lepidopterous larvae, 19, 23 Sand-wasps, 87 as models for mimicry, 267 Saiiba ant, 133 nests where found, 133 domes, 133 underground earth-works, extra- ordinary dimensions of, 133 Mr. Bates on, 134 chambers, entrances, latter generally closed, 134 leaf-cutting propensities, 134 as mushroom growers, 135 Saus-ure, on entrances to nest hornet, 179 Sawflies, defensive fluid of larvae, 244 as objects of mimicry, 267 Scarabaeidae beetles, larvae of, 98 Scolytiis destructor, larvae, 98 Segments, body of insects formed of, 15 of thorax, how recognised, 17 Scsia apiformis, caterpillars of, 95 Sesiidse, mimicry of, 265 Sexton or burying beetles, 37 Sexual difference of form and colour, an explanation of, 263 Sexual colours, made use of for warning, 251 ; their similarity, 251 their transition to warning colours, 251 and warning colours, difference between, 250 INDEX 297 Shelters for pupae, 8 Silk of lepidopterous larva, 19 Similarity between unpalatable forms, their possession of element of mimicry, 252 Size, of inssct-architecture as compared with makers, 118 of tracheae of larvae of bee family, 27 Skin of insects, 18. 20 Snakes as models for mimicry, 270 Social, wasps and bees, feeding their young, 48, 49 homes, 118, 154 caterpillars, societies of, 119 Solitary, homes, various kinds of, 73 bees, 73 architects, homes of, for own use, 95, 107 ; for young, 72 Spangle galls, 92 Specialised forms of protective resem- blance, 210 Sphecia apiformis, mimicry of, 265 Sphingidae as honey-gatherers, 64 Sphinx ligustri, increasa of, 7 brilliant colour of, enhances conceal- ment, 208 change of colour of larva, 227 Prof. Meldola on, 227 Sphinx moths, length of pupal period of, ii Spiders, resembling ants, explanation of, 270, 272, 273 ordinary tube-constructing, 109 homes of, English, 109, 115 protective resemblance of, 222 resemblance to flowers, 224 resemblance to excreta of birds, 226 ; explained by natural selection, 226 mimicking ants, 269, 272, 273 Spilosoma menthastri, probably a model for mimicry, 260 Spinneret, the, 19 Spiracles, 26 position and design of, 27 of abdomen and of thorax compared, 27 St. Hilaire, on honey wasps, 199 Standing army of bull's horn, 149 Stick caterpillars, special protective re- semblance of, 2 10 Stingless bees of South America, 163, 166 Meliponae, 163, 166 supposed presence of several fertile females in colonies, 164, 166 homes of, compared with hive, 16}. M. fasciculata^ 164 ; appoints senti- nels to guard the gates, 165 Trigona, nests of, 166 Stomach, the, 21, 22 digestion of food in, 22 Story of life-history of insects, 5 Strange food of young of fossorial hyinen- pptera, 85 Strepsiptera, parasites on bees, 37 Structure of a wing, 18 Study of structures implicated in metamor- phoses, 15 Synageles picata, mimicry of, 269 Syneiitosyna formica, mimicry of, 269 TABBY, larva of, 41 Tatuz jnorio, and nest, 192 Thorax, development of, 17 appendages of, 16, 18 segments of, how recognised, 17 great development of, when it occurs, 18 Thrips, metamorphoses of, 3 Tiger beetle, a, an object of mimicry, 268 Tiger beetles, habits of larvae, 100 colour of, an exact reproduction of colours of surroundings, 208 Tinea tapetzella, tube of, 103 Tineina and Tortricina, caterpillars of, 101 Titanus giganteiis, larvae of, 99 Tracheae, and spiracles, function of, 26 formation of, 26, 27 development into vesicles, 28 ; use of, 28 of larvae of bee family, size of, 27 Tracheal vessels of humble bee, 29 Trap-door spiders, no typical nest, no barricading door, 112 of southern Europe, 113 multiplication of precautionary mea- sures, 113 Mr. Gosse on, 112 Treat, Mrs., on a dome-constructing spider, 114 Tree wasps, British, 175 Trichoptera, homes of larvae, 105 Trigona, exists both in Old and New Worlds, 163, 166 honey of, 166 nests of, 1 66 True legs of insects, their nature, develop- ment, 16, 17 Tube of Tinea tapetzella, 103 Turret spiders, 113 Two classes of legs, number of, 16 U UNDERSIDES of wings of butterflies, sober tints of, 209 imitative tints of, 209, 215, 216, 253 concealment afforded effective, 210, 216 Unpleasant qualities possessed by cater- pillars, 244, 245, 246 Upholsterer, the, bee, 84 VAKIABLE protective resemblance, 231 history of discovery of, in pupse of butterflies, 232 in caterpillars, Mr. Poulton on, 239 INDEX Variable protective resemblance in cocoons, 240 probable in certain perfect insects, 240 no explanation of the origin of colour, 240 Vegetable food, choice of, almost limitless for insects, 34 Vegetation that is poisonous or distasteful to higher animals, 35 Vertebrates, insects which mimic, 270, 271 Vespa. britannica, beautiful globe-like dwelling of, 175 Vespa orientalis, an object of mimicry, 266 Vespa vulgaris, particulars of home, 168 formation of home, and of society, 169 dissolution of company, 173 pendent nests of, 175 as object of mimicry, 272 Vespidae, 167 beauty and delicacy of architecture, 167 building material, 168 disposition of combs, 168 Vine, caterpillars destructive to, 101 Volucella, aggressive mimicry of, 272 Voyages of locusts, 29 W " WALKING LEAF " insect, 221 "Walking stick" insects, 221, 222 Wallace, on Kalliina paralekta, 215, 217 on a "walking stick" insect, 221 on dimorphism, 230 on protective mimicry in British le- pidoptera, 260 on liability of female butterflies to assume protection of mimicry, 262 Warning, sexual colours made use of for, 2 5i Warning, a, bright colour as, 247 Warning colours, and those produced by courtship, distinction between, 250 defences usually attended by, 249 and patterns, resemblance between, 249 in caterpillars, 244, 245 Wasp, defensive bright colours of, 247 Wasps, as objects of mimicry, 265, 266, 267, 272 British tree, 175 as honey gatherers, 198, 200 Wasps' nest, enlargement of, 175 papery envelope of, its fabrication ; imbrication of sheets, 176, 177 Wasps' nests, without cover, 180, 183 with cover, but not distinct, 184 Water-spiders, 115 Wax, caterpillars with a liking for, 42 Weevils, subject to parasites, 40 colour of, exactly reproduces colour of surroundings, 209 White ants as objects of mimicry, 272 White Ermine Moth, probable object of mimicry, 260 Wild bees, British. 74, 79, 82, 154 Wings, condition of, at assumption of imago state, 13 of butterflies, meaning of dull colours of undersides of, 209, 210 attachment of, 17 structure of, 18 association of, with function of re- spiration, 1 8 broad expanse of, of showy butterflies, one explanation of, 253 Wood carved by F. fuliginosa becomes black, 147 Wood ant, home, 120 various names of, 120 external conformation of home, 120 internal plan of dome, and dwelling underground, 120, 122 doors, 122 swarming, and regulation of society, 123 ' care of young, 124 a solitary "queen" as founder of a colony, 126 singularity of preference for open-air life, 127 precaution against attack, 122, 127 closure of apertures of dwelling, 127 in Scotland, 128 in warm climates, 128 Wood-carving ants, 146 F. fnliginosa, 146 F. aethiops, habits of, 147 F.jffava, habits of, 147 Xylocopa violacea, interesting home of, 75 YELLOW ant, ingenuity in building, 147 THE END. 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