lOS ANGELA ^OF-CAUFORto ^^^'fr Si X~^v £ •CAIIFO% x — .4r § | 1 1 I a UNIVERSE £ i 33NVS01*N UN!VER% ^AOS ANGELA g 3 30NVSOV 1 S I § rj- OC s 5^ £ 3 s i < 1 § 1 8 I $ * * 5 WfW>J» I 3 § ^flWITCHO^ 'SftEAiNrf ^ME-UNIVER% ^lOSANGEtfj^. 8 1 PS ?- si 1 S ^ WP i^ fr ^^»i-5 ^ ^AHVMIB^ ^AbvaaiH^ ^•LIBRARY^ ^EUNIVERS/A ^lOS-ANCElfju — ' *"" ^ g ,^*v ^ % "*? 1 I " ! I THE GLOW-WORM AND OTHER BEETLES BOOKS BY J. HENRI FABRE THE LIFE OF THE SPIDER THE LIFE OF THE FLY THE MASON-BEES BRAMBLE-BEES AND OTHERS THE HUNTING WASPS THE LIFE OF THE CATERPILLAR THE LIFE OF THE GRASSHOPPER THE SACRED BEETLE AND OTHERS THE MASON-WASPS THE GLOW-WORM AND OTHER BEETLES THE GLOW-WORM AND OTHER BEETLES BY J. HENRI FABRE TRANSLATED BY ALEXANDER TEIXEIRA DE MATTOS FELLOW OP THB ZOOLOGICAL SOCIETY OF LONDON NEW YORK DODD, MEAD AND COMPANY 1919 COPYEIOHT, 1919 BY DODD, MEAD AND COMPANY, INC. QL 576 CONTENTS PAGE I THE GLOW-WORM .... I II THE SITARES 28 III THE PRIMARY LARVA OF THE SITARES 46 IV THE PRIMARY LARVA OF THE OIL- BEETLES 84 V HYPERMETAMORPHOSIS . . .109 VI CEROCOM^E, MYLABRES AND ZO- NITES 144 VII THE CAPRICORN . . . .185 VIII THE PROBLEM OF THE SIREX . 207 IX THE DUNG-BEETLES OF THE PAM- PAS 235 X INSECT COLOURING . . . . 273 XI THE BURYING-BEETLES : THE BURIAL 294 xii THE BURYING-BEETLES: EXPERI- MENTS 319 Contents PAGE XIII THE GIANT SCARITES . . -352 XIV THE SIMULATION OF DEATH . 370 XV SUICIDE OR HYPNOSIS? . . . 390 XVI THE CRIOCERES 411 xvii THE CRIOCERES (continued) . 428 XVIII THE CLYTHR^: . . , . . 446 XIX THE CLYTHR^: THE EGG . . 463 TRANSLATOR'S NOTE This is the second volume on Beetles in the complete English edition of Henri Fa- bre's entomological works. The first is en- titled The Sacred Beetle and Others; the second and the third will be known as The Life of the Weevil and More Beetles respec- tively. The Glow-worm, which gives its name to the present book, did not form part of the Souvenirs entomologiques as originally pub- lished. It is one of two essays written spe- cially, at my request, for translation into English, towards the close of Henri Fabre's life; in fact, this and The Ant-lion, a short essay for children, were the last works that came from the veteran author's pen. The Glow-worm appeared first in the Century Magazine. Of the remaining chapters, sev- eral have appeared in various periodicals, notably the English Review and in Land and Water, the editor and proprietors of which admirable weekly have shown the most en- lightened interest in Fabre's work. Translator's Note A part of the chapter entitled The Dung- beetles of the Pampas figures in Messrs. Adam & Charles Black's volume, The Life and Love of the Insect (New York: the Macmillan Co.), translated by myself; and the chapters on the Capricorn and Burying- beetles will be found in Mr. T. Fisher Un- win's volume, The Wonders of Instinct (New York: the Century Co.), translated by myself and Mr. Bernard Miall, which also contains The Glow-worm. These chapters are included in the present edition by consent of and arrangement with the publishers named. Lastly, Mr. Bernard Miall has earned my gratitude by the valuable assistance which he has given me in preparing the translation of the greater part of this volume. ALEXANDER TEIXEIRA DE MATTOS. CHELSEA, 5 September, 1919. CHAPTER I THE GLOW-WORM "C^EW insects in our climes vie in popular ••• fame with the Glow-worm, that curious little animal which, to celebrate the little joys of life, kindles a beacon at its tail-end. Who does not know it, at least by name? Who has not seen it roam amid the grass, like a spark fallen from the moon at its full? The Greeks of old called it Aa/Mroupw, mean- ing, the bright-tailed. Science employs the same term: it calls the lantern-bearer, Lam- pyris noctiluca, LIN. In this case, the common name is inferior to the scientific phrase, which, when translated, becomes both expressive and accurate. In fact, we might easily cavil at the word " worm." The Lampyris is not a worm at all, not even in general appearance. He has six short legs, which he well knows how to use; he is a gad-about, a trot-about. In the adult state, the male is correctly garbed in wing-cases, like the true Beetle that he is. The female is an ill-favoured thing who The Glow- Worm and Other Beetles knows naught of the delights of flying: all her life long, she retains the larval shape, which, for the rest, is similar to that of the male, who himself is imperfect so long as he has not achieved the maturity that comes with pairing-time. Even in this initial stage, the word " worm " is out of place. We French have the expression " Naked as a worm," to point to the lack of any defensive covering. Now the Lampyris is clothed, that is to say, he wears an epidermis of some consistency; moreover, he is rather richly coloured: his body is dark brown all over, set off with pale pink on the thorax, especially on the lower surface. Finally, each segment is decked at the hinder edge with two spots of a fairly bright red. A costume like this was never worn by a worm. Let us leave this ill-chosen denomination and ask ourselves what the Lampyris feeds upon. That master of the art of gastro- nomy, Brillat-Savarin,1 said : " Show me what you eat and I will tell you what you are." A similar question should be addressed, by way of a preliminary, to every insect whose habits we propose to study, for, from the 1Anselme Brillat-Savarin (1755-1826), author of La Psychologie du gout. — Translator's Note, The Glow-Worm least to the greatest in the zoological pro- gression, the stomach sways the world; the data supplied by food are the chief of all the documents of life. Well, in spite of his in- nocent appearance, the Lampyris is an eater of flesh, a hunter of game; and he follows his calling with rare villainy. His regular prey is the Snail. This detail has long been known to en- tomologists. What is not so well-known, what is not known at all yet, to judge by what I have read, is the curious method of attack, of which I have seen no other instance any- where. Before he begins to feast, the Glow-worm administers an anaesthetic: he chloroforms his victim, rivalling in the process the won- ders of our modern surgery, which renders the patient insensible before operating on him. The usual game is a small Snail hardly the size of a cherry, such as, for in- stance, Helix variabilis, DRAP., who, in the hot weather, collects in clusters on the stiff stubble and on other long, dry stalks, by the roadside, and there remains motionless, in profound meditation, throughout the scorch- ing summer days. It is in some such resting- place as this that I have often been privileged to light upon the Lampyris banqueting on the The Glow- Worm and Other Beetles prey which he had just paralyzed on its shaky support by his surgical artifices. But he is familiar with other preserves. He frequents the edges of the irrigating- ditches, with their cool soil, their varied vegetation, a favourite haunt of the mol- lusc. Here, he treats the game on the ground; and, under these conditions, it is easy for me to rear him at home and to fol- low the operator's performance down to the smallest detail. I will try to make the reader a witness of the strange sight. I place a little grass in a wide glass jar. In this I install a few Glow- worms and a provision of Snails of a suit- able size, neither too large nor too small, chiefly Helix variabilis. We must be pa- tient and wait. Above all, we must keep an assiduous watch, for the desired events come unexpectedly and do not last long. Here we are at last. The Glow-worm for a moment invesigates the prey, which, according to its habit, is wholly withdrawn in the shell, except the edge of the mantle, which projects slightly. Then the hunter's weapon is drawn, a very simple weapon, but one that cannot be plainly perceived with- out the aid of a lens. It consists of two mandibles bent back powerfully into a hook, 4 The Glow- Worm very sharp and as thin as a hair. The micro- scope reveals the presence of a slender groove running throughout the length. And that is all. The insect repeatedly taps the Snail's mantle with its instrument. It all happens with such gentleness as to suggest kisses rather than bites. As children, teasing one another, we used to talk of " tweaksies " to express a slight squeeze of the finger-tips, something more like a tickling than a serious pinch. Let us use that word. In conver- sing with animals, language loses nothing by remaining juvenile. It is the right way for the simple to understand one another. The Lampyris doles out his tweaks. He distributes them methodically, without hurry- ing, and takes a brief rest after each of them, as though he wished to ascertain the effect produced. Their number is not great: half-a-dozen, at most, to subdue the prey and deprive it of all power of movement. That other pinches are administered later, at the time of eating, seems very likely, but I can- not say anything for certain, because the sequel escapes me. The first few, however — there are never many — are enough to impart inertia and loss of all feeling to the mollusc, thanks to the prompt, I might al- 5 The Glow-Worm and Other Beetles most say, lightning methods of the Lampyris, who, beyond a doubt, instils some poison or other by means of his grooved hooks. Here is the proof of the sudden efficacity of those twitches, so mild in appearance : I take the Snail from the Lampyris, who has operated on the edge of the mantle some four or five times. I prick him with a fine needle in the fore-part, which the animal, shrunk into its shell, still leaves exposed. There is no quiver of the wounded tissues, no reaction against the brutality of the needle. A corpse itself could not give fewer signs of life. Here is something even more conclusive: chance occasionally gives me Snails attacked by the Lampyris while they are creeping along, the foot slowly crawling, the ten- tacles swollen to their full extent. A few disordered movements betray a brief excite- ment on the part of the mollusc and then everything ceases: the foot no longer slugs; the front-part loses its graceful swan-neck curve ; the tentacles become limp and give way under their weight, dangling feebly like a broken stick. This conditions persists. Is the Snail really dead? Not at all, for I am free to resuscitate the seeming corpse. After two or three days of that singular con- 6 The Glow- Worm dition which is no longer life and yet not death, I isolate the patient and, although this is not really necessary to success, I give him a douche which will represent the shower so dear to the able-bodied mollusc. In about a couple of days, my prisoner, but lately injured by the Glow-worm's treachery, is re- stored to his normal state. He revives, in a manner; he recovers movement and sensi- bility. He is affected by the stimulus of a needle; he shifts his place, crawls, puts out his tentacles, as though nothing unusual had occurred. The general torpor, a sort of deep drunkenness, has vanished outright. The dead returns to life. What name shall we give to that form of existence which, for a time, abolishes the power of movement and the sense of pain? I can see but one that is approximately suitable: anaesthesia. The exploits of a host of Wasps whose flesh- eating grubs are provided with meat that is motionless though not dead l have taught us the skilful art of the paralyzing insect, which numbs the locomotory nerve-centres with its venom. We have now a humble little animal that first produces complete anaes- 1 Cf. The Hunting Wasps, by J. Henri Fabre, translated by Alexander Teixeira de Mattos : passim. — Translator's Note. The Glow- Worm and Other Beetles thesia in its patient. Human science did not in reality invent this art, which is one of the wonders of our latter-day surgery. Much earlier, far back in the centuries, the Lampy- ris and, apparently, others knew it as well. The animal's knowledge had a long start of ours; the method alone has changed. Our operators proceed by making us inhale the fumes of ether or chloroform; the insect proceeds by injecting a special virus that comes from the mandibular fangs in in- finitesimal doses. Might we not one day be able to benefit by this hint? What glorious discoveries the future would have in store for us, if we understood the beastie's secrets better ! What does the Lampyris want with ansesthetical talent against a harmless and moreover eminently peaceful adversary, who would never begin the quarrel of his own accord? I think I see. We find in Algeria a Beetle known as Drilus maroccanus, who, though non-luminous, approaches our Glow- worm in his organization and especially in his habits. He too feeds on land molluscs. His prey is a Cyclostome with a graceful spiral shell, tight-closed with a stony lid which is attached to the animal by a powerful muscle. The lid is a movable door which is 8 The Glow- Worm quickly shut by the inmate's mere withdrawal into his house and as easily opened when the hermit goes forth. With this system of closing, the abode becomes inviolable; and the Drilus knows it. Fixed to the surface of the shell by an adhesive apparatus whereof the Lampyris will presently show us the equivalent, he re- mains on the look-out, waiting, if necessary, for whole days at a time. At last, the need of air and food oblige the besieged non- combatant to show himself; at least, the door is set slightly ajar. That is enough. The Drilus is on the spot and strikes his blow. The door can no longer be closed and the assailant is henceforth master of the fortress. Our first impression is that the muscle moving the lid has been cut with a quick-acting pair of shears. This idea must be dismissed. The Drilus is not well enough equipped with jaws to gnaw through a fleshy mass so promptly. The operation has to succeed at once, at the first touch: if not, the animal attacked would retreat, still in full vigour, and the siege must be recommenced, as ardu- ous as ever, exposing the insect to fasts in- definitely prolonged. Although I have never come across the Drilus, who is a stranger to my district, I conjecture a method of attack 9 The Glow-Worm and Other Beetles very similar to that of the Glow-worm. Like our own Snail-eater, the Algerian in- sect does not cut its victim into small pieces : it renders it inert, chloroforms it by means of a few tweaks which are easily distributed, if the lid but half-opens for a second. That will do. The besieger thereupon enters and, in perfect quiet, consumes a prey incapable of the least muscular effort. That is how I see things by the unaided light of logic. Let us now return to the Glow-worm. When the Snail is on the ground, creeping, or even shrunk into his shell, the attack never presents any difficulty. The shell possesses no lid and leaves the hermit's fore-part to a great extent exposed. Here, on the edges of the mantle contracted by the fear of danger, the mollusc is vulnerable and in- capable of defence. But it also frequently happens that the Snail occupies a raised posi- tion, clinging to the tip of a grass-stalk or perhaps to the smooth surface of a stone. This support serves him as a temporary lid; it wards off the aggression of any churl who might try to molest the inhabitant of the cabin, always on the express condition that no slit show itself anywhere on the protecting circumference. If, on the other hand, in the frequent case when the shell does not fit its The Glow-Worm support quite closely, some point, however tiny, be left uncovered, this is enough for the subtle tools of the Lampyris, who just nibbles at the mollusc and at once plunges him into that profound immobility which favours the tranquil proceedings of the con- sumer. These proceedings are marked by extreme prudence. The assailant has to handle his victim gingerly, without provoking contract- ions which would make the Snail let go his support and, at the very least, precipitate him from the tall stalk whereon he is bliss- fully slumbering. Now any game falling to the ground would seem to be so much sheer loss, for the Glow-worm has no great zeal for hunting-expeditions : he profits by the dis- coveries which good luck sends him, without undertaking assiduous searches. It is es- sential, therefore, that the equilibrium of a prize perched on the top of a stalk and only just held in position by a touch of glue should be disturbed as little as possible during the onslaught; it is necessary that the assailant should go to work with infinite circumspect- ion and without producing pain, lest any muscular reaction should provoke a fall and endanger the prize. As we see, sudden and profound anaesthesia is an excellent means of The Glow- Worm and Other Beetles enabling the Lampyris to attain his object, which is to consume his prey in perfect quiet. What is his manner of consuming it? Does he really eat, that is to say, does he divide his food piecemeal, does he carve it into minute particles, which are afterwards ground by a chewing-apparatus? I think not. I never see a trace of solid nourishment on my captives' mouths. The Glow-worm does not eat in the strict sense of the word: he drinks his fill; he feeds on a thin gruel into which he transforms his prey by a method recalling that of the maggot. Like the flesh-eating grub of the Fly, he too is able to digest before consuming; he liquefies his prey before feeding on it. This is how things happen: a Snail has been rendered insensible by the Glow-worm. The operator is nearly always alone, even when the prize is a large one, like the Com- mon Snail, Helix aspersa. Soon a number of guests hasten up — two, three or more — and, without any quarrel with real proprietor, all alike fall to. Let us leave them to them- selves for a couple of days and then turn the shell, with the opening downwards. The contents flow out as easily as would soup from an overturned saucepan. When the 12 The Glow- Worm sated diners retire from this gruel, only in- significant leavings remain. The matter is obvious: by repeated tiny bites, similar to the tweaks which we saw distributed at the outset, the flesh of the mollusc is converted into a gruel on which the various banqueters nourish themselves without distinction, each working at the broth by means of some special pepsine and each taking his own mouthfuls of it. In conse- quence of this method, which first converts the food into a liquid, the Glow-worm's mouth must be very feebly armed apart from the two fangs which sting the patient and inject the anaesthetic poison and, at the same time, no doubt, the serum capable of turn- ing the solid flesh into fluid. These two tiny implements, which can just be examined through the lens, must, it seems, have some other object. They are hollow and in this resemble those of the Ant-lion, which sucks and drains its capture without having to divide it; but there is this great difference, that the Ant-lion leaves copious remnants, which are afterwards flung outside the fun- nel-shaped trap dug in the sand, whereas the Glow-worm, that expert liquefier, leaves nothing, or next to nothing. With similar tools, the one simply sucks the blood of its 13 The Glow- Worm and Other Beetles prey and the other turns every morsel of his to account, thanks to a preliminary lique- faction. And this is done with exquisite precision, though the equilibrium is sometimes anything but steady. My rearing-glasses supply me with magnificent examples. Crawling up the sides, the Snails imprisoned in my appa- ratus sometimes reach the top, which is closed with a glass pane, and fix themselves to it by means of a speck of glair. This is a mere temporary halt, in which the mollusc is miserly with its adhesive product, and the merest shake is enough to loosen the shell and send it to the bottom of the jar. Now it is not unusual for the Glow-worm to hoist himself to the top, with the help of a certain climbing-organ that makes up for his weak legs. He selects his quarry, makes a minute inspection of it to find an entrance- slit, nibbles it a little, renders it insensible and, without delay, proceeds to prepare the gruel which he will consume for days on end. When he leaves the table, the shell is found to be absolutely empty; and yet this shell, which was fixed to the glass by a very faint stickiness, has not come loose, has not even shifted its position in the smallest degree : without any protest from the hermit 14 The Glow- Worm gradually converted into broth, it has been drained on the very spot at which the first attack was delivered. These small details tell us how promptly the anaesthetic bite takes effect; they teach us how dexterously the Glow-worm treats his Snail without causing him to fall from a very slippery vertical sup- port and without even shaking him on his slight line of adhesion. Under these conditions of equilibrium, the operator's short, clumsy legs are obviously not enough; a special accessory apparatus is needed to defy the danger of slipping and to seize the unseizable. And this apparatus the Lampyris possesses. At the hinder end of the animal we see a white spot which the lens separates into some dozen short, fleshy appendages, sometimes gathered into a cluster, sometimes spread into a rosette. There is your organ of adhesion and locomo- tion. If he would fix himself somewhere, even on a very smooth surface, such as a grass-stalk, the Glow-worm opens his rosette and spreads it wide on the support, to which it adheres by its own stickiness. The same organ, rising and falling, opening and clo- sing, does much to assist the act of progress- ion. In short, the Glow-worm is a new sort of self-propelled cripple, who decks his hind- is The Glow-Worm and Other Beetles quarters with a dainty white rose, a kind of hand with twelve fingers, not jointed, but moving in every direction: tubular fingers which do not seize, but stick. The same organ serves another purpose: that of a toilet-sponge and brush. At a moment of rest, after a meal, the Glow-worm passes and repasses the said brush over his head, back, sides and hinder-parts, a per- formance made possible by the flexibility of his spine. This is done point by point, from one end of the body to the other, with a scrupulous persistency that proves the great interest which he takes in the operation. What is his object in thus sponging himself, in dusting and polishing himself so carefully? It is a question, apparently, of removing a few atoms of dust or else some traces of viscidity that remain from the evil contact with the snail. A wash and brush-up is not superfluous when one leaves the tub in which the mollusc has been treated. If the Glow-worm possessed no other talent than that of chloroforming his prey by means of a few tweaks resembling kisses, he would be unknown to the vulgar herd; but he also knows how to light himself like a beacon; he shines, which is an excellent manner of achieving fame. Let us consider 16 The Glow-Worm more particularly the female, who, while re- taining her larval shape, becomes marriage- able and glows at her best during the hottest part of summer. The lighting-apparatus occupies the last three segments of the ab- domen. On each of the first two, it takes the form, on the ventral surface, of a wide belt covering almost the whole of the arch; on the third, the luminous part is much less and consists simply of two small crescent- shaped markings, or rather two spots which shine through to the back and are visible both above and below the animal. Belts and spots emit a glorious white light, delicately tinged with blue. The general lighting of the Glow-worm thus comprises two groups: first, the wide belts of the two segments pre- ceding the last; secondly, the two spots of the final segments. The two belts, the ex- clusive attribute of the marriageable female, are the part richest in light: to glorify her wedding, the future mother dons her bright- est gauds ; she lights her two resplendent scarves. But, before that, from the time of the hatching, she had only the modest rush- light of the stern. This efflorescence of light is the equivalent of the final metamorphosis, which is usually represented by the gift of wings and flight. Its brilliance heralds the 17 The Glow- Worm and Other Beetles pairing-time. Wings and flight there will be none : the female retains her humble larval form, but she kindles her blazing beacon. The male, on his side, is fully transformed, changes his shape, acquires wings and wing- cases; nevertheless, like the female, he pos- sesses, from the time when he is hatched, the pale lamp of the end segment. This lumin- ous aspect of the stern is characteristic of the entire Glow-worm tribe, independently of sex and season. It appears upon the bud- ding grub and continues throughout life un- changed. And we must not forget to add that it is visible on the dorsal as well as on the ventral surface, whereas the two large belts peculiar to the female shine only under the abdomen. My hand is not so steady nor my sight so good as once they were, but, as far as they allow me, I consult anatomy for the structure of the luminous organs. I take a scrap of the epidermis and manage to separate pretty neatly half of one of the shining belts. I place my preparation under the microscope. On the skin, a sort of white-wash lies spread, formed of a very fine, granular substance. This is certainly the light-producing matter. To examine this white layer more closely is beyond the power of my weary eyes. Just 18 The Glow- Worm beside it is a curious air-tube, whose short and remarkably wide stem branches suddenly into a sort of bushy tuft of very delicate rami- fications. These creep over the luminous sheet, or even dip into it. That is all. The luminescence, therefore, is controlled by the respiratory organs and the work pro- duced is an oxidization. The white sheet supplies the oxidizable matter and the thick air-tube spreading into a tufty bush dis- tributes the flow of air over it. There re- mains the question of the substance whereof this sheet is formed. The first suggestion was phosphorus, in the chemist's sense of the word. The Glow-worm has been calcined and treated with the violent reagents that bring the simple substances to light; but no one, so far as I know, has obtained a satis- facory answer along these lines. Phos- phorus seems to play no part here, in spite of the name of phosphorescence which is some- times bestowed upon the Glow-worm's gleam. The answer lies elsewhere, no one knows where. We are better informed as regards an- other question. Has the Glow-worm a free control of the light which he emits? Can he turn it on or down or put it out as he pleases? Has he an opaque screen which 19 The Glow-Worm and Other Beetles is drawn over the flame at will, or is that flame always left exposed? There is no need for any such mechanism: the insect has something better for its revolving light. The thick tube supplying the light-pro- ducing sheet increases the flow of air and the light is intensified; the same air-tube, swayed by the animal's will, slackens or even suspends the passage of air and the light grows fainter or even goes out. It is, in short, the mechanism of a lamp which is regulated by the access of air to the wick. Excitement can set the attendant air-duct in motion. We must here distinguish be- tween two cases: that of the gorgeous scarves, the exclusive ornament of the female ripe for matrimony, and that of the modest fairy-lamp on the last segment, which both sexes kindle at any age. In the second case, the extinction caused by a flurry is sudden and complete, or nearly so. In my noc- turnal hunts for young Glow-worms, measur- ing about 5 millimetres long,1 I can plainly see the glimmer on the blades of grass; but, should the least false step disturb a neigh- bouring twig, the light goes out at once and the coveted insect becomes invisible. Upon the full-grown females, lit up with their 1 .195 inch. — Translator's Note. 20 The Glow- Worm nuptial scarves, even a violent start has but a slight effect and often none at all. I fire a gun beside a wire-gauze cage in which I am rearing my menagerie of females in the open air. The explosion produces no result. The illumination continues, as bright and placid as before. I take a spray and rain down a slight shower of cold water upon the flock. Not one of my animals puts out its light; at the very most, there is a brief pause in the radiance; and then only in some cases. I send a puff of smoke from my pipe into the cage. This time, the pause is more marked. There are even some ex- tinctions, but these do not last long. Calm soon returns and the light is renewed as brightly as ever. I take some of the captives in my fingers, turn and return them, tease them a little. The illumination continues and is not much diminished, if I do not press too hard with my thumb. At this period, with the pairing close at hand, the insect is in all the fervour of its passionate splendour; and nothing short of very serious reasons would make it put out its signals altogether. All things considered, there is not a doubt but that the Glow-worm himself manages his lighting-apparatus, extinguishing and re- kindling it at will; but there is one point at 21 The Glow-Worm and Other Beetles which the voluntary agency of the insect is without effect. I detach a strip of the epidermis showing one of the luminescent sheets and place it in a glass tube, which I close with a plug of damp wadding, to avoid too rapid an evaporation. Well, this scrap of carcass shines away merrily, although not quite as brilliantly as on the living body. Life's aid is now superfluous. The oxi- dizable substance, the luminescent sheet, is in direct communication with the surrounding atmosphere; the flow of oxygen through an air-tube is not necessary; and the luminous emission continues to take place, in the same way as when it is produced by the contact of the air with the real phosphorus of the chem- ists. Let us add that, in aerated water, the luminousness continues as brilliant as in the free air, but that it is extinguished in water deprived of its air by boiling. No better proof could be found of what I have already propounded, namely, that the Glow-worm's light is the effect of a slow oxidization. The light is white, calm and soft to the eyes and suggests a spark dropped by the full moon. Despite its splendour, it is a very feeble illuminant. If we move a Glow-worm along a line of print, in perfect darkness, we can easily make out the letters, one by one, The Glow-Worm and even words, when these are not too long; but nothing more is visible beyond a narrow zone. A lantern of this kind soon tires the reader's patience. Suppose a group of Glow-worms placed almost touching one another. Each of them sheds its glimmer, which ought, one would think, to light up its neighbours by reflexion and give us a clear view of each individual specimen. But not at all : the luminous party is a chaos in which our eyes are unable to distinguish any definite form at a medium distance. The collective lights confuse the link-bearers into one vague whole. Photography gives us a striking proof of this. I have a score of females, all at the height of their splendour, in a wire-gauze cage in the open air. A tuft of thyme forms a grove in the centre of their establishment. When night comes, my captives clamber to this pinnacle and strive to show off their luminous charms to the best advantage at every point of the horizon, thus forming along the twigs marvellous clusters from which I expected magnificent effects on the photographer's plates and paper. My hopes are disappointed. All that I obtain is white, shapeless patches, denser here and less dense there according to the numbers forming the 23 The Glow-Worm and Other Beetles group. There is no picture of the Glow- worms themselves; not a trace either of the tuft of thyme. For want of satisfactory light, the glorious firework is represented by a blurred splash of white on a black ground. The beacons of the female Glow-worms are evidently nuptial signals, invitations to the pairing; but observe that they are lighted on the lower surface of the abdomen and face the ground, whereas the summoned males, whose flights are sudden and uncertain, travel overhead, in the air, sometimes a great way up. In its normal position, therefore, the glittering lure is concealed from the eyes of those concerned; it is covered by the thick bulk of the bride. The lantern ought really to gleam on the back and not under the belly; otherwise the light is hidden under a bushel. The anomaly is corrected in a very in- genious fashion, for every female has her little wiles of coquetry. At nightfall, every evening, my caged captives make for the tuft of thyme with which I have thoughtfully furnished the prison and climb to the top of the upper branches, those most in sight. Here, instead of keeping quiet, as they did at the foot of the bush just now, they indulge in violent exercises, twist the tip of their very 24 The Glow- Worm flexible abdomen, turn it to one side, turn it to the other, jerk it in every direction. In this way, the search-light cannot fail to gleam, at one moment or another, before the eyes of every male who goes a-wooing in the neighbourhood, whether on the ground or in the air. It is very like the working of the revolving mirror used in catching Larks. If station- ary, the little contrivance would leave the bird indifferent; turning and breaking up its light in rapid flashes, it excites it. While the female Glow-worm has her tricks for summoning her swains, the male, on his side, is provided with an optical ap- paratus suited to catch from afar the least reflection of the calling-signal. His corse- let expands into a shield and overlaps his head considerably in the form of a peaked cap or eye-shade, the object of which appears to be to limit the field of vision and concen- trate the view upon the luminous speck to be discerned. Under this arch are the two eyes, which are relatively enormous, exceed- ingly convex, shaped like a skull-cap and con- tiguous to the extent of leaving only a narrow groove for the insertion of the antennae. This double eye, occupying almost the whole 25 The Glow- Worm and Other Beetles face of the insect and contained in the ca- vern formed by the spreading peak of the corselet, is a regular Cyclop's eye. At the moment of the pairing, the illumina- tion becomes much fainter, is almost extin- guished; all that remains alight is the humble fairy-lamp of the last segment. This dis- creet night-light is enough for the wedding, while, all around, the host of nocturnal in- sects, lingering over their respective affairs, murmur the universal marriage-hymn. The laying follows very soon. The round, white eggs are laid, or rather strewn at random, without the least care on the mother's part, either on the more or less cool earth or on a blade of grass. These brilliant ones know nothing at all of family-affection. Here is a very singular thing: the Glow- worm's eggs are luminous even when still contained in the mother's womb. If I hap- pen by accident to crush a female big with germs that have reached maturity, a shiny streak runs along my fingers, as though I had broken some vessel filled with a phos- phorescent fluid. The lens shows me that I am wrong. The luminosity comes from the cluster of eggs forced out of the ovary. Be- sides, as laying-time approaches, the phos- phorescence of the eggs is already made mani- 2)6 The Glow- Worm fest without this clumsy midwifery. A soft opalescent light shines through the skin of the belly. The hatching follows soon after the lay- ing. The young of either sex have two lit- tle rush-lights on the last segment. At the approach of the severe weather, they go down into the ground, but not very far. In my rearing-jars, which are supplied with fine and very loose earth, they descend to a depth of three or four inches at most. I dig up a few in mid-winter. I always find them car- rying their faint stern-light. About the month of April, they come up again to the surface, there to continue and complete their evolution. From start to finish, the Glow-worm's life is one great orgy of light. The eggs are luminous; the grubs likewise. The full- grown females are magnificent light-houses, the adult males retain the glimmer which the grubs already possessed. We can under- stand the object of the feminine beacon; but of what use is all the rest of the pyrotechnic display? To my great regret, I cannot tell. It is and will be, for many a day to come, per- haps for all time, the secret of animal physics, which is deeper than the physics of the books. CHAPTER II THE SITARES 'T^HE high banks of sandy clay in the ••• country round about Carpentras are the favourite haunts of a host of Bees and Wasps, those lovers of a thoroughly sunny aspect and of soils that are easy to excavate. Here, in the month of May, two Antho- phorae l are especially abundant, gatherers of honey and, both of them, makers of sub- terranean cells. One, A. parietina, builds at the entrance of her dwelling an advanced fortification, an earthy cylinder, wrought in open work, like that of the Odynerus,2 and curved like it, but of the width and length of a man's finger. When the community is a populous one, we stand amazed at the rustic ornamentation formed by all these stalactites of clay hanging from the facade. The other, 1 Cf. The Mason-bees, by J. Henri Fabre, translated by Alexander Teixeira de Mattos: chap. viii. ; and Bram- ble-bees and Others, by J. Henri Fabre, translated by Alex- ander Teixeira de Mattos: passim. — Translator's Note. 2 Cf. The Mason-wasps, by J. Henri Fabre, translated by Alexander Teixeira de Mattos: chaps, vi. and x. — Translator's Note. 28 The Shares A. pilipes, who is very much more frequent, leaves the opening of her corridor bare'. The chinks between the stones in old walls and abandoned hovels, the surfaces of ex- cavations in soft sandstone or marl, are found suitable for her labours; but the fa- vourite spots, those to which the greatest num- ber of swarms resort, are vertical stretches, exposed to the south, such as are afforded by the cuttings of deeply sunken roads. Here, over areas many yards in width, the wall is drilled with a multitude of holes, which im- part to the earthy mass the look of some enormous sponge. These round holes might be fashioned with an auger, so regular are they. Each is the entrance to a winding cor- ridor, which runs to a depth of four to six inches. The cells are distributed at the far end. If we would witness the labours of the industrious Bee, we must repair to her work- shop during the latter half of May. Then, but at a respectful distance, if, as novices, we are afraid of being stung, we may contem- plate, in all its bewildering activity, the tumultuous, buzzing swarm, busied with the building and the provisioning of the cells. It is most often during the months of August and September, those happy months of the summer holidays, that I have visited 29 The Glow- Worm and Other Beetles the banks inhabited by the Anthophora. At this period all is silent near the nests; the work has long been completed; and numbers of Spiders' webs line the crevices or plunge their silken tubes into the Bee's corridors. Let us not, however, hastily abandon the city once so populous, so full of life and bustle and no\7 deserted. A few inches below the surface, thousands of larvae and nymphs, im- prisoned in their cells of clay, are resting until the coming spring. Might not such a succulent prey as these larvae, paralysed and incapable of defence, tempt certain parasites who are industrious enough to attain them? Here indeed are some Flies clad in a dis- mal livery, half-black, half-white, a species of Anthrax (A. sinuata),1 flying indolently from gallery to gallery, doubtless with the object of laying their eggs there; and here are others, more numerous, whose mission is fulfilled and who, having died in harness, are hanging dry and shrivelled in the Spiders' webs. Elsewhere the entire surface of a per- pendicular bank is hung with the dried corpses of a Beetle (Sitaris humeralis) , slung, like the Flies, in the silken meshes of 1 Cf. The Life of the Fly, by J. Henri Fabre, translated by Alexander Teixeira de Mattos: chaps, ii. and iv. — Translator's Note. The Shares the Spiders. Among these corpses some male Sitares circle, busy, amorous, heedless of death, mating with the first female that passes within reach, while the fertilized females thrust their bulky abdomens into the opening of a gallery and disappear into it backwards. It is impossible to mistake the situation: some grave interest attracts to this spot these two insects, which, within a few days, make their appearance, mate, lay their eggs and die at the very doors of the Anthophora's dwellings. Let us now give a few blows of the pick to the surface beneath which the singular in- cidents already in our mind must be oc- curring, beneath which similar things oc- curred last year; perhaps we shall find some evidence of the parasitism which we sus- pected. If we search the dwellings of the Anthophorae during the early days of August, this is what we see : the cells forming the sup- erficial layer are not like those situated at a greater depth. This difference arises from the fact that the same establishment is ex- ploited simultaneously by the Anthophora and by an Osmia (O. tricornis)1 as is proved by an observation made at the working- 1 Cf. Bramble-bees and Others; passim. — Translator's Note. 31 The Glow-Worm and Other Beetles period, in May. The Anthophorae are the actual pioneers, the work of boring the gal- leries is wholly theirs; and their cells are situated right at the end. The Osmia profits by the galleries which have been abandoned either because of their age, or because of the completion of the cells occupying the most distant part; she builds her cells by dividing these corridors into unequal and inartistic chambers by means of rude earthen parti- tions. The Osmia's sole achievement in the way of masonry is confined to these parti- tions. This, by the way, is the ordinary building-method adopted by the various Os- miae, who content themselves with a chink between two stones, an empty Snail-shell, or the dry and hollow stem of some plant, wherein to build their stacks of cells, at small expense, by means of light partitions of mor- tar. The cells of the Anthophora, with their faultless geometrical regularity and their per- fect finish, are works of art, excavated, at a suitable depth, in the very substance of the loamy bank, without any manufactured part save the thick lid that closes the orifice. Thus protected by the prudent industry of their mother, well out of reach in their dis- tant, solid retreats, the Anthophora's larvae 32 The Sitares are devoid of the glandular apparatus de- signed for secreting silk. They therefore never spin a cocoon, but lie naked in their cells, whose inner surface has the polish of stucco. In the Osmia's cells, on the other hand, means of defence are required, for these are situated in the surface layer of the bank; they are irregular in form, rough inside and barely protected, by their thin earthen par- titions, against external enemies. The Os- mia's larvae, in fact, contrive to enclose them- selves in an egg-shaped cocoon, dark brown in colour and very strong, which preserves them both from the rough contact of their shapeless cells and from the mandibles of voracious parasites, Acari,1 Cleri 2 and An- threni,3 those manifold enemies whom we find prowling in the galleries, seeking whom they may devour. It is by means of this equipoise between the mother's talents and the larva's that the Osmia and the Antho- phora, in their early youth, escape some part 1 Mites and Ticks. — Translator's Note. 2 A genus of Beetles of which certain species (Clerus aplarius and C. alvearius) pass their preparatory state in the nests of Bees, where they feed on the grubs. — Trans- lator's Note, 3 Another genus of Beetles. The grub of A. musa- orum, the Museum Beetle, is very destructive to insect- collections. — Translator's Note. 33 The Glow- Worm and Other Beetles of the dangers which threaten them. It is easy therefore, in the bank excavated by these two Bees, to recognize the property of either species by the situation and form of the cells and also by their contents, which consist, with the Anthophora, of a naked larva and, with the Osmia, of a larva enclosed in a cocoon. On opening a certain number of these co- coons, we end by discovering some which, in place of the Osmia's larva, contain each a curiously shaped nymph. These nymphs, at the least shock received by their dwelling, in- dulge in extravagant movements, lashing the walls with their abdomen till the whole house shakes and dances. And, even if we leave the cocoon intact, we are informed of their presence by a dull rustle heard inside the silken dwelling the moment after we move it. The fore-part of this nymph is fashioned like a sort of boar's-snout armed with six strong spikes, a multiple ploughshare, emi- nently adapted for burrowing in the soil. A double row of hooks surmounts the dorsal ring of the four front segments of the ab- domen. These are so many grappling-irons, with whose assistance the creature is en- abled to progress in the narrow gallery dug by the snout. Lastly, a sheaf of sharp points 34 The Shares forms the armour of the hinder-part. If we examine attentively the surface of the ver- tical wall which contains the various nests, it will not be long before we discover nymphs like those which we have been describing, with one extremity held in a gallery of their own diameter, while the fore-part projects freely into the air. But these nymphs are reduced to their cast skins, along the back and head of which runs a long slit through which the perfect insect has escaped. The purpose of the nymph's powerful weapons is thus made manifest: it is the nymph that has to rend the tough cocoon which imprisons it, to excavate the tightly-packed soil in which it is buried, to dig a gallery with its six- pointed snout and thus to bring to the light the perfect insect, which apparently is in- capable of performing these strenuous tasks for itself. And in fact these nymphs, taken in their cocoons, have in a few days' time given me a feeble Fly (Anthrax sinuata) who is quite in- capable of piercing the cocoon and still more of making her exit through a soil which I cannot easily break up with my pick. Al- though similar facts abound in insect history, we always notice them with a lively interest. They- tell us of -an incomprehensible power 35 The Glow-Worm and Other Beetles which suddenly, at a given moment, irre- sistibly commands an obscure grub to aban- don the retreat in which it enjoys security, in order to make its way through a thousand difficulties and to reach the light, which would be fatal to it on any other occasion, but which is necessary to the perfect insect, which could not reach it by its own efforts. But the layer of Osmia-cells has been re- moved; and the pick now reaches the Antho- phora's cells. Among these cells are some which contain larvae and which result from the labours of last May; others, though of the same date, are already occupied by the perfect insect. The precocity of metamor- phosis varies from one larva to another; however, a few days' difference of age is enough to explain these inequalities of de- velopment. Other cells, as numerous as the first, contain a parasitical Hymenopteron, a Melecta (M. armata), likewise in the per- fect state. Lastly, there are some, indeed many, which contain a singular egg-shaped shell, divided into segments with projecting breathing-pores. This shell is extremely thin and fragile; it is amber-coloured and so transparent that one can distinguish quite plainly, through its sides, an adult Sitaris (S. humeralis), who occupies the interior and 36 The Shares is struggling as though to set herself at liberty. This explains the presence here, the pairing and the egg-laying of the Sitares whom we but now saw roaming, in the com- pany of the Anthrax-flies, at the entrance to the galleries of the Anthophorae. The Os- mia and the Anthophora, the joint owners of the premises, have each their parasite: the Anthrax attacks the Osmia and the Sitaris the Anthophora. But what is this curious shell in which the Sitaris is invariably enclosed, a shell unex- ampled in the Beetle order? Can this be a case of parasitism in the second degree, that is, can the Sitaris be living inside the chrysalis of a first parasite, which itself exists at the cost of the Anthophora's larva or of its pro- visions? And, even so, how can this para- site, or these parasites, obtain access to a cell which seems to be inviolable, because of the depth at which it lies, and which, moreover, does not reveal, to the most careful examina- tion under the magnifying-glass, any violent inroad on the enemy's part? These are the questions that presented themselves to my mind when for the first time, in 1855, I ob- served the facts which I have just related. Three years of assiduous observation enabled me to add one of its most astonishing chap- 37 The Glow- Worm and Other Beetles ters to the story of the formation of insects. After collecting a fairly large number of these enigmatical shells containing adult Sitares, I had the satisfaction of observing, at leisure, the emergence of the perfect insect from the shell, the act of pairing and the laying of the eggs. The shell is easily broken; a few strokes of the mandibles, dis- tributed at random, a few kicks are enough to deliver the perfect insect from its fragile prison. In the glass jars in which I kept my Sitares I saw the pairing follow very closely upon the first moments of freedom. I even wit- nessed a fact which shows emphatically how imperious, in the perfect insect, is the need to perform, without delay, the act intended to ensure the preservation of its race. A female, with her head already cut out of the shell, is anxiously struggling to release her- self entirely; a male, who has been free for a couple of hours, climbs on the shell and, tugging here and there, with his mandibles, at the fragile envelope, strives to deliver the female from her shackles. His efforts are soon crowned with success; and, though the female is still three parts swathed in her swaddling-bands, the coupling takes place immediately, lasting about a minute. During 38 The Shares the act, the male remains motionless on the top of the shell, or on the top of the female when the latter is entirely free. I do not know whether, in ordinary circumstances, the male occasionally thus helps the female to gain her liberty; to do so he would have to penetrate into a cell containing a female, which, after all, is not beyond his powers, seeing that he has been able to escape from his own. Still, on the actual site of the cells, the coupling is generally performed at the entrance to the galleries of the Anthophorae; and then neither of the sexes drags about with it the least shred of the shell from which it has emerged. After mating, the two Sitares proceed to clean their legs and antennae by drawing them between their mandibles; then each goes his own way. The male cowers in a crevice of the earthen bank, lingers for two or three days and perishes. The female also, after getting rid of her eggs, which she does with- out delay, dies at the entrance to the corridor in which the eggs are laid. This is the ori- gin of all those corpses swinging in the Spiders' web with which the neighbourhood of the Anthophora's dwellings is upholstered. Thus the Sitares in the perfect state live long enough only to mate and to lay their The Glow-Worm and Other Beetles eggs. I have never seen one save upon the scene of their loves, which is also that of their death; I have never surprised one browsing on the plants near at hand, so that, though they are provided with a normal digestive apparatus, I have grave reasons to doubt whether they actually take any nourishment whatever. What a life is theirs! A fortnight's feasting in a store- house of honey; a year of slumber under- ground; a minute of love hi the sunlight; then death ! Once fertilized, restlessly the female at once proceeds to seek a favourable spot wherein to lay her eggs. It was important to note where this exact spot is. Does the female go from cell to cell, confiding an egg to the succulent flanks of each larva, whether this larva belong to the Anthophora or to a parasite of hers, as the mysterious shell whence the Sitaris emerges would incline one to believe ? This method of laying the eggs, one at a time in each cell, would appear to be essential, if we are to explain the facts al- ready ascertained. But then why do the cells usurped by the Sitares retain not the slightest trace of the forcible entry which is indis- pensable? And how is it that, in spite of lengthy investigations during which my per- 40 The Shares severance has been kept up by the keenest de- sire to cast some light upon all these mys- teries, how is it, I say, that I have never come across a single specimen of the supposed parasites to which the shell might be at- tributed, since this shell appears not to be a Beetle's? The reader would hardly suspect how my slight acquaintance with entomology was unsettled by this inextricable maze of contradictory facts. But patience ! We may yet obtain some light. Let us begin by observing precisely at what spot the eggs are laid. A female has just been fertilized before my eyes; she is forthwith placed in a large glass jar, into which I put, at the same time, some clods of earth containing Anthophora-cells. These cells are occupied partly by larvae and partly by nymphs that are still quite white; some are slightly open and afford a glimpse of their contents. Lastly, in the inner surface of the cork which closes the jar I sink a cylin- drical well, a blind alley, of the same diameter as the corridors of the Anthophora. In or- der that the insect, if it so desire, may enter this artificial corridor, I lay the bottle hori- zontally. The female, painfully dragging her big abdomen, perambulates all the nooks and 41 The Glow- Worm and Other Beetles corners of her makeshift dwelling, exploring them with her palpi, which she passes every- where. After half an hour of groping and careful investigation, she ends by selecting the horizontal gallery dug in the cork. She thrusts her abdomen into this cavity and, with her head hanging outside, begins her laying. Not until thirty-six hours later was the operation completed; and during this in- credible lapse of time the patient creature re- mained absolutely motionless. The eggs are white, oval and very small. They measure barely two-thirds of a milli- metre * in length. They stick together slightly and are piled in a shapeless heap which might be likened to a good-sized pinch of the unripe seeds of some orchid. As for their number, I will admit that it tried my patience to no purpose. I do not, however, believe that I am exaggerating when I esti- mate it as at least two thousand. Here are the data on which I base this figure : the lay- ing, as I have said, lasts thirty-six hours; and my frequent visits to the female working in the cavity in the cork convinced me that there was no perceptible interruption in the suc- cessive emission of the eggs. Now less than a minute elapses between the arrival of one 1 .026 inch.— Translator's Note. 42 The Shares egg and that of the next; and the number of these eggs cannot therefore be lower than the number of minutes contained in thirty- six hours, or 2160. But the exact number is of no importance : we need only note that it is very large, which implies, for the young larvae issuing from the eggs, very numerous chances of destruction, since so lavish a sup- ply of germs is necessary to maintain the species in the requisite proportions. Enlightened by these observations and in- formed of the shape, the number and the arrangement of the eggs, I searched the gal- leries of the Anthophorae for those which the Sitares had laid there and invariably found them gathered in a heap inside the galleries, at a distance of an inch or two from the orifice, which is always open to the outer world. Thus, contrary to what one was to some extent entitled to suppose, the eggs are not laid in the cells of the pioneer Bee ; they are simply dumped in a heap inside the en- trance to her dwelling. Nay more, the mother does not make any protective struc- ture for them; she takes no pains to shield them from the rigours of winter; she does not even attempt, by stopping for a short dis- tance, as best she can, the entrance-lobby in which she has laid them, to protect them 43 The Glow-Worm and Other Beetles from the thousand enemies that threaten them ; for, as long as the frosts of winter have not arrived, these open galleries are trodden by Spiders, by Acari, by Anthrenus-grubs and other plunderers, to whom these eggs, or the young larvae about to emerge from them, must be a dainty feast. In consequence of the mother's heedlessness, the number of those who escape all these voracious hunters and the inclemencies of the weather must be curiously small. This perhaps explains why she is compelled to make up by her fecundity for her deficient industry. The hatching occurs a month later, about the end of September or the beginning of October. The season being still propitious, I was led to suppose that the young larvae must at once make a start and disperse, in order that each might seek to gain access, through some imperceptible fissure, to an Anthophora-cell. This presumption turned out to be entirely at fault. In the boxes in which I had placed the eggs laid by my cap- tives, the young larvae, little black creatures at most a twenty-fifth of an inch long, did not move away, provided though they were with vigorous legs; they remained higgledy- piggledy with the white skins of the eggs whence they had emerged. 44 The Shares In vain I placed within their reach lumps of earth containing nests of the Anthophora, open cells, larvae and nymphs of the Bee : nothing was able to tempt them; they per- sisted in forming, with the egg-skins, a powdery heap of speckled black and white. It was only by drawing the point of a needle through this pinch of living dust that I was able to provoke an active wriggling. Apart from this, all was still. If I forcibly re- moved a few larvae from the common heap, they at once hurried back to it, in order to hide themselves among the rest. Perhaps they had less reason to fear the cold when thus collected and sheltered beneath the egg- skins. Whatever may be the motive that impels them to remain thus gathered in a heap, I recognized that none of the means suggested by my imagination succeeded in forcing them to abandon the little spongy mass formed by the skins of the eggs, which were slightly glued together. Lastly, to as- sure myself that the larvae, in the free state, do not disperse after they are hatched, I went during the winter to Carpentras and in- spected the banks inhabited by the Antho- phorae. There, as in my boxes, I found the larvae piled into heaps, all mixed up with the skins of the eggs. 45 CHAPTER III THE PRIMARY LARVA OF THE SITARES NOTHING new happens before the end of the following April. I shall profit by this long period of repose to tell you more about the young larva, of which I will begin by giving a description. Its length is a twenty-fifth of an inch, or a little less. It is hard as leather, a glossy greenish black, con- vex above and flat below, long and slender, with a diameter increasing gradually from the head to the hinder extremity of the meta- thorax, after which it rapidly diminishes. Its head is a trifle longer than it is wide and is slightly dilated at the base; it is pale-red near the mouth and darker about the ocelli. The labrum forms a segment of a circle; it is reddish, edged with a small number of very short, stiff hairs. The mandibles are powerful, red-brown, curved and sharp; when at rest they meet without crossing. The maxillary palpi are rather long, consist- ing of two cylindrical sections of equal length, the outer ending in a very short bristle. The jaws and the lower lip are not sufficiently 46 The Primary Larva of the Sitares visible to lend themselves to accurate de- scription. The antennae consist of two cylindrical segments, equal in length, not very definitely divided; these segments are nearly as long as those of the palpi; the outer is surmounted by a cirrus whose length is as much as thrice that of the head and tapers off until it be- comes invisible under a powerful pocket-lens. Behind the base of either antennae are two ocelli, unequal in size and almost touching. The thoracic segments are of equal length and increase gradually in width from front to back. The prothorax is wider than the head, but is narrower in front than at the base and is slightly rounded at the sides. The legs are of medium length and fairly robust, ending in a long, powerful, sharp and very mobile claw. On the haunch and thigh of each leg is a long cirrus, like that of the antennae, almost as long as the whole limb and standing at right angles to the plane of locomotion when the creature moves. There are a few stiff bristles on the legs. The abdomen has nine segments, of prac- tically equal length, but shorter than those of the thorax and diminishing very rapidly in width toward the last. Fixed below the eighth segment, or rather below the strip of 47 The Glow-Worm and Other Beetles membrane separating this segment and the last, we see two spikes, slightly curved, short, but with strong, sharp, hard points, and placed one to the right and the other to the left of the median line. These two ap- pendages are able, by means of a mechanism recalling, on a smaller scale, that of the Snail's horns, to withdraw into themselves, as a result of" the membranous character of their base. They can also retreat under the eighth segment, borne, as they are, by the anal segment, when this last, as it contracts, withdraws into the eighth. Lastly, the ninth or anal segment bears on its hinder edge two long cirri, like those of the legs and the an- tennae, curving backwards from tip to base. At the rear of this segment a fleshy nipple appears, more or less prominent; this is the anus. I do not know where the stigmata are placed; they have evaded my investigations, though these were undertaken with the aid of the microscope. When the larva is at rest, the various seg- ments overlap evenly; and the membranous intervals, corresponding with the articula- tions, do not show. But, when the larva walks, all the articulations, especially those of the abdominal segments, are distended and end by occupying almost as much 48 The Primary Larva of the Shares space as the horny arches. At the same time the anal segment emerges from the sheath formed by the eighth; the anus, in turn, is stretched into a nipple; and the two points of the penultimate ring rise, at first slowly, and then suddenly stand up with an abrupt motion similar to that of a spring when released. In the end, these two points diverge like the horns of a crescent. Once this complex apparatus is unfolded, the tiny creature is ready to crawl upon the most slippery surface. The last segment and its anal button are curved at right angles to the axis of the body; and the anus comes and presses upon the surface of locomotion, where it ejects a tiny drop of transparent, treacly fluid, which glues and holds the little creature firmly in position, supported on a sort of tripod formed by the anal button and the two cirri of the last segment. If we are observing the animal's manner of locomotion on a strip of glass, we can hold the strip in a vertical position, or even turn it upside down, or shake it lightly, without causing the larva to become detached and fall, held fast as it is by the glutinous secretion of the anal button. If it has to proceed along a surface where there is no danger of a fall, the microscopic The Glow-Worm and Other Beetles creature employs another method. It crooks its belly and, when the two spikes of the eighth segment, now fully outspread, have found a firm support by ploughing, so to speak, the surface of locomotion, it bears upon that base and pushes forward by ex- panding the various abdominal articulations. This forward movement is also assisted by the action of the legs, which are far from remaining inactive. This done, it casts an- chor with the powerful claws of its feet; the abdomen contracts ; the various segments draw together; and the anus, pulled forward, obtains a fresh purchase, with the aid of the two spikes, before beginning the second of these curious strides. During these manoeuvres, the cirri of the flanks and thighs drag along the supporting surface and by their length and elasticity ap- pear fitted only to impede progress. But let us not be in a hurry to conclude that we have discovered an inconsistency : the least of creatures is adapted to the conditions amid which it has to live; there is reason to be- lieve that these filaments, far from hamper- ing the pigmy's progress, must, in normal circumstances, be of some assistance to it. Even the little that we have just learnt shows us that the young Sitaris-larva is not The Primary Larva of the Sitares called upon to move on an ordinary surface. The spot, whatever it may be like, where this larva is to live later exposes it to the risk of many dangerous falls, since, in order to pre- vent them, it is not only equipped with strong and extremely mobile talons and a steel-shod crescent, a sort of ploughshare capable of biting into the most highly polished substance, but is further provided with a viscous liquid, sufficiently tenacious and adhesive to hold it in position without the help of other appli- ances. In vain I racked my brains to guess what the substance might be, so shifting, so uncertain and so perilous, which the young Sitares are destined to inhabit; and I disco- vered nothing to explain the necessity for the structure which I have described. Convinced beforehand, by an attentive examination of this structure, that I should witness some peculiar habits, I waited with eager impa- tience for the return of the warm weather, never doubting that by dint of persevering observation the mystery would be disclosed to me next spring. At last this spring, so fervently desired, arrived; I brought to bear all the patience, all the imagination, all the insight and discernment that I may possess; but, to my utter shame and still greater re- gret, the secret escaped me. Oh, how pain- Si The Glow- Worm and Other Beetles ful are those tortures of indecision, when one has to postpone till the following year an investigation which has led to no result ! My observations made during the spring of 1856, although purely negative, neverthe- less have an interest of their own, because they prove the inaccuracy of certain supposi- tions to which the undeniable parasitism of the Sitares naturally inclines us. I will there- fore relate them in a few words. At the end of April, the young larvae, hitherto motion- less and concealed in the spongy heap of the egg-skins, emerge from their immobility, scatter and run about in all directions through the boxes and jars in which they have passed the winter. By their hurried gait and their indefatigable evolutions we readily guess that they are seeking something which they lack. What can this something be, unless it be food? For remember that these larvae were hatched at the end of September and that since then, that is to say, for seven long months, they have taken no nourishment, though they have spent this period in the full enjoyment of their vitality, as I was able to assure myself all through the winter by irri- tating them, and not in a state of torpor similar to that of the hibernating animals. 52 The Primary Larva of the Sitares From the moment of their hatching they are doomed, although full of life, to an absolute abstinence of seven months' duration; and it is natural to suppose, when we see their pre- sent excitement, that an imperious hunger sets them bustling in this fashion. The desired nourishment could only be the contents of the cells of the Anthophora, since we afterwards find the Sitares in these cells. Now these contents are limited to honey or larvae. It just happens that I have kept some Anthophora-cells occupied by larvae or nymphs. I place a few of these, some open, some closed, within reach of the young Sitares, as I had already done directly after the hatching. I even slip the Sitares into the cells : I place them on the sides of the larva, a succulent morsel to all appearances; I do all sorts of things to tempt their appetite; and, after exhausting my ingenuity, which continues fruitless, I remain convinced that my famished grubs are seeking neither the larvae nor nymphs of the Anthophora. Let us now try honey. We must obviously employ honey prepared by the same species of Anthophora as that at whose cost the Sitares live. But this Bee is not very com- mon in the neighbourhood of Avignon; and 53 The Glow-Worm and Other Beetles my engagements at the college l do not allow me to absent myself for the purpose of repairing to Carpentras, where she is so abundant. In hunting for cells provisioned with honey I thus lose a good part of the month of May; however, I end by finding some which are newly sealed and which be- long to the right Anthophora. I open these cells with the feverish impatience of a sorely- tried longing. All goes well : they are half- full of fluid, dark, nauseating honey, with the Bee's lately-hatched larva floating on the surface. This larva is removed; and taking a thousand precautions, I lay one or more Sitares on the surface of the honey. In other cells I leave the Bee's larva and insert Sitares, placing them sometimes on the honey and sometimes on the inner wall of the cell or simply at the entrance. Lastly, all the cells thus prepared are put in glass tubes, which enable me to observe them readily, without fear of disturbing my famished guests at their meal. But what am I saying? Their meal? There is no meal! The Sitares, placed at the entrance to a cell, far from seeking to 1 Fabre, as a young man, was a master at Avignon College. Cf. The Life of the Fly: chaps, xii., xiii., xix. and xx. — Translator's Note. 54 The Primary Larva of the Shares make their way in, leave it and go roaming about the glass tube ; those which have been placed on the inner surface of the cells, near the honey, emerge precipitately, half-caught in the glue and tripping at every step ; lastly, those which I thought I had favoured the most, by placing them on the honey itself, struggle, become entangled in the sticky mass and perish in it, suffocated. Never did ex- periment break down so completely! Lar- vae, nymphs, cells, honey: I have offered you them all ! Then what do you want, you fiendish little creatures? Tired of all these fruitless attempts, I ended where I ought to have begun: I went to Carpentras. But it was too late: the Anthophora had finished her work; and I did not succeed in seeing anything new. During the course of the year I learnt from Leon Dufour,1 to whom I had spoken of the Sitares, that the tiny creature which he had found on the Andrenae 2 and described under 1 Jean Marie Leon Dufour (1780-1865), an army surg- eon who served with distinction in several campaigns, and subsequently practised as a doctor in the Landes, where he attained great eminence as a naturalist. Fabre often refers to him as the Wizard of the Landes. Cf. The Life of the Spider, by J. Henri Fabre, translated by Alexander Teixeira de Mattos: chap. i. ; and The Life of the Fly: chap. i. — Translator's Note. 2 A genus of Burrowing Bee, the most numerous in species among the British Bees. — Translator's Note. 55 The Glow- Worm and Other Beetles the generic name of Triungulinus, was recognized later by Newport l as the larva of a Meloe, or Oil-beetle. Now it so hap- pened that I had found a few Oil-beetles in the cells of the same Anthophora that nour- ishes the Sitares. Could there be a similar- ity of habits between the two kinds of in- sects? This idea threw a sudden light for me upon the subject; but I had plenty of time in which to mature my plans: I had another year to wait. When April came, my Sitaris-larvae began, as usual, to bestir themselves. The first Bee to appear, an Osmia, is dropped alive into a glass jar containing a few of these larvae; and after a lapse of some fifteen minutes I inspect them through the pocket-lens. Five Sitares are embedded in the fleece of the thorax. It is done, the problem's solved! The larvae of the Sitares, like those of the Oil-beetles, cling like grim death to the fleece of their generous host and make him carry them into the cell. Ten times over I repeat the experiment with the various Bees that come to plunder the lilac flowering outside my window and in particular with male An- 1 George Newport (1803-1854), an English surgeon and naturalist, president of the Entomological Society from 1844 to 1845 and an expert in insect anatomy. — Trans- tutor's Note. 56 The Primary Larva of the Sitares thophorae; the result is still the same: the larvae embed themselves in the hair of the Bees' thorax. But after so many disappoint- ments one becomes distrustful and it is better to go and observe the facts upon the spot; besides, the Easter holidays fall very con- veniently and afford me the leisure for my observations. I will admit that my heart was beating a little faster than usual when I found myself once again standing in front of the perpend- icular bank in which the Anthophora nests. What will be the result of the experi- ment? Will it once more cover me with con- fusion? The weather is cold and rainy; not a Bee shows herself on the few spring flowers that have come out. Numbers of Anthopho- rae cower, numbed and motionless, at the en- trance to the galleries. With the tweezers, I extract them one by one from their lurking- places, to examine them under the lens. The first has Sitaris-larvae on her thorax; so has the second; the third and fourth likewise; and so on, as far as I care to pursue the examination. I change galleries ten times, twenty times ; the result is invariable. Then, for me, occurred one of the moments which come to those who, after considering and re- considering an idea for years and years from 57 The Glow- Worm and Other Beetles every point of view, are at last able to cry: " Eureka ! " On the days that followed, a serene and balmy sky enabled the Anthophorae to leave their retreats and scatter over the country- side and despoil the flowers. I renewed my examination on those Anthophorae flying incessantly from one flower to another, whether in the neighbourhood of the places where they were born or at great distances from these places. Some were without Sitaris-larvae; others, more numerous, had two, three, four, five or more among the hairs of their thorax. At Avignon, where I have not yet seen Sitaris humeralis, the same species of Anthophora, observed at almost the same season, while pillaging the lilac- blossom, was always free of young Sitaris- grubs; at Carpentras, on the contrary, where there is not a single Anthophora-colony with- out Sitares, nearly three-quarters of the specimens which I examined carried a few of these larvae in their fleece. But, on the other hand, if we look for these larvae in the entrance-lobbies where we found them, a few days ago, piled up in heaps, we no longer see them. Conse- quently, when the Anthophorae, having opened their cells, enter the galleries to 58 The Primary Larva of the Sitares reach the exit and fly away, or else when the bad weather and the darkness bring them back there for a time, the young Sitaris- larvas, kept on the alert in these same gal- leries by the stimulus of instinct, attach them- selves to the Bees, wriggling into their fur and clutching it so firmly that they need not fear a fall during the long journeys of the insect which carries them. By thus attaching themselves to the Anthophorae the young Sitares evidently intend to get themselves carried, at the opportune moment, into the victualled cells. One might even at first sight believe that they live for some time on the Anthophora's body, just as the ordinary parasites, the va- rious species of Lice, live on the body of the animal that feeds them. But not at all. The young Sitares, embedded in the fleece, at right angles to the Anthophora's body, head inwards, rump outwards, do not stir from the point which they have selected, a point near the Bee's shoulders. We do not see them wandering from spot to spot, ex- ploring the Anthophora's body, seeking the part where the skin is more delicate, as they would certainly do if they were really de- riving some nourishment from the juices of the Bee. On the contrary, they are nearly 59 The Glow-Worm and Other Beetles always established on the toughest and hard- est part of the Bee's body, on the thorax, a little below the insertion of the wings, or, more rarely, on the head; and they remain absolutely motionless, fixed to the same hair, by means of the mandibles, the feet, the closed crescent of the eighth segment and, lastly, the glue of the anal button. If they chance to be disturbed in this position, they reluctantly repair to another point of the thorax, pushing their way through the insect's fur and in the end fastening on to another hair, as before. To confirm my conviction that the young Sitaris-grubs do not feed on the Anthophora's body, I have sometimes placed within their reach, in a glass jar, some Bees that have long been dead and are completely dried up. On these dry corpses, fit at most for gnaw- ing, but certainly containing nothing to suck, the Sitaris-larvae took up their customary position and there remained motionless as on the living insect. They obtain nothing, therefore, from the Anthophora's body; but perhaps they nibble her fleece, even as the Bird-lice nibble the birds' feathers? To do this, they would require mouth- parts endowed with a certain strength and, in particular, horny and sturdy jaws, whereas 60 The Primary Larva of the Sitares their jaws are so fine that a microscopic ex- amination failed to show them to me. The larvse, it is true, are provided with powerful mandibles ; but these finely-pointed mandibles, with their backward curve, though excellent for tugging at food and tearing it to pieces, are useless for grinding it or gnawing it. Lastly, we have a final proof of the passive condition of the Sitaris-larvae on the body of the Anthophorae in the fact that the Bees do not appear to be in any way incommoded by their presence, since we do not see them trying to rid themselves of the grubs. Some Anthophorae which were free from these grubs and some others which were carrying five or six upon their bodies were placed separately in glass jars. When the first dis- turbance resulting from their captivity was appeased, I could see nothing peculiar about those occupied by the young Sitares. And, if all these arguments were not sufficient, I might add that a creature which has already been able to spend seven months without food and which in a few days' time will pro- ceed to drink a highly-flavoured fluid would be guilty of a singular inconsistency if it were to start nibbling the dry fleece of a Bee. It therefore seems to me undeniable that the young Sitares settle on the Anthophora's body 61 The Glow-Worm and Other Beetles merely to make her carry them into the cells which she will soon be building. But until then the future parasites must hold tight to the fleece of their hostess, despite her rapid evolutions among the flowers, despite her rubbing against the walls of the galleries when she enters to take shel- ter and, above all, despite the brushing which she must often give herself with her feet to dust herself and keep spick and span. Kence no doubt the need for that curious apparatus which no standing or moving upon ordinary surfaces could explain, as was said above, when we were wondering what the shifting, swaying, dangerous body might be on which the larva would have to establish itself later. This body is a hair of a Bee who makes a thousand rapid journeys, now diving into her narrow galleries, now forcing her way down the tight throat of a corolla, and who never rests except to brush herself with her feet and remove the specks of dust collected by the down which covers her. We can now easily understand the use of the projecting crescent whose two horns, by closing together, are able to take hold of a hair more easily than the most delicate tweezers; we perceive the full value of the tenacious adhesive provided by the anus to The Primary Larva of the Sitares save the tiny creature, at the least sign of danger, from an imminent fall; we realize lastly the useful function that may be fulfilled by the elastic cirri of the flanks and legs, which are an absolute and most embarrassing superfluity when walking upon a smooth sur- face, but which, in the present case, penetrate like so many probes into the thickness of the Anthophora's down and serve as it were to anchor the Sitaris-larva in position. The more we consider this arrangement, which seems modelled by a blind caprice so long as the grub drags itself laboriously over a smooth surface, the more do we marvel at the means, as effective as they are varied, which are lavished upon this fragile creature to help it to preserve its unstable equi- librium. Before I describe what becomes of the Sitaris-grubs on leaving the body of the An- thophorae, I must not omit to mention one very remarkable peculiarity. All the Bees invaded by these grubs that have hitherto been observed have, without one exception, been male Anthophorae. Those whom I drew from their lurking-places were males; those whom I caught upon the flowers were males; and, in spite of the most active search, I failed to find a single female at liberty. 63 The Glow- Worm and Other Beetles The cause of this total absence of females is easy to understand. If we remove a few clods from the area occupied by the nests, we see that, though all the males have already opened and aban- doned their cells, the females, on the con- trary, are still enclosed in theirs, but on the point of soon taking flight. This appearance of the males almost a month before the emer- gence of the females is not peculiar to the Anthophorae; I have observed it in many other Bees and particularly in the Three- horned Osmia (0. tricornis}, who inhabits the same site as the Hairy-footed Antho- phora (A. pilipes). The males of the Os- mia make their appearance even before those of the Anthophora and at so early a season that the young Sitaris-larvae are per- haps not yet aroused by the instinctive im- pulse which urges them to activity. It is no doubt to their precocious awakening that the males of the Osmia owe their ability to traverse with impunity the corridors in which the young Sitaris-grubs are heaped to- gether, without having the latter fasten to their fleece; at least, I cannot otherwise ex- plain the absence of these larvae from the backs of the male Osmiae, since, when we place them artificially in the presence of these 64 The Primary Larva of the Sitares Bees, they fasten on them as readily as on the Anthophorse. The emergence from the common site be- gun by the male Osmiae is continued by the male Anthophorae and ends with the almost simultaneous emergence of the female Os- mias and Anthophorae. I was easily able to verify this sequence by observing at my own place, in the early spring, the dates at which the cells, collected during the previous autumn, were broken. At the moment of their emergence, the male Anthophorae, passing through the gal- leries in which the Sitaris-larvae are waiting on the alert, must pick up a certain number of them; and those among them who, by entering empty corridors, escape the enemy on this first occasion will not evade him for long, for the rain, the chilly air and the darkness bring them back to their former homes, where they take shelter now in one gallery, now in another, during a great part of April. This constant traffic of the males in the entrance-lobbies of their houses and the prolonged stay which the bad weather often compels them to make provide the Sitares with the most favourable opportunity for slipping into the Bees' fur and taking up their position. Moreover, when this state of 65 The Glow-Worm and Other Beetles affairs has lasted a month or so, there can be only very few if any larvae left wandering about without having attained their end. At that period I was unable to find them any- where save on the body of the male An- thophora. It is therefore extremely probable that, on their emergence, which takes place as May draws near, the female Anthophorae do not pick up Sitaris-larvae in the corridors, or pick up only a number which will not compare with that carried by the males. In fact, the first females that I was able to observe in April, in the actual neighbourhood of the nests, were free from these larvae. Never- theless it is upon the females that the Sitaris- larvae must finally establish themselves, for the males upon whom they now are cannot introduce them into the cells, since they take no part in the building or provisioning. There is therefore, at a given moment, a transfer of Sitaris-larvae from the male An- thophorae to the females; and this transfer is, beyond a doubt, effected during the union of the sexes. The female finds in the male's embraces both life and death for her offspring; at the moment when she surrenders herself to the male for the preservation of her race, the vigilant parasites pass from the 66 The Primary Larva of the Shares male to the female, with the extermination of that same race in view. In support of these deductions, here is a fairly conclusive experiment, though it re- produces the natural circumstances but roughly. On a female taken in her cell and therefore free from Sitares, I place a male who is infested with them; and I keep the two sexes in contact, suppressing their unruly movements as far as I am able. After fifteen or twenty minutes of this enforced proximity, the female is invaded by one or more of the larvae which at first were on the male. True, experiment does not always succeed under these imperfect conditions. By watching at Avignon the few Antho- phorae that I succeeded in discovering, I was able to detect the precise moment of their work; and on the following Thursday,1 the 2ist of May, I repaired in all haste to Carpentras, to witness, if possible, the en- trance of the Sitares into the Bee's cells. I was not mistaken: the works were in full swing. In front of a high expanse of earthj a swarm stimulated by the sun, which floods it with light and heat, is dancing a crazy 1 Thursday is the weekly holiday in French schools. — Translator's Note. 67 The Glow- Worm and Other Beetles ballet. It is a hover of Anthophorae, a few feet thick and covering an area which matches the sort of house-front formed by the per- pendicular soil. From the tumultuous heart of the cloud rises a monotonous, threatening murmur, while the bewildered eye strays through the inextricable evolutions of the eager throng. With the rapidity of a light- ning-flash thousands of Anthophorae are in- cessantly flying off and scattering over the country-side in search of booty; thousands of others also are incessantly arriving, laden with honey or mortar, and keeping up the formidable proportions of the swarm. I was at that time something of a novice as regards the nature of these insects: " Woe," said I to myself, " woe to the reckless wight bold enough to enter the heart of this swarm and, above all, to lay a rash hand upon the dwellings under construction ! Forthwith surrounded by the furious host, he would expiate his rash attempt, stabbed by a thousand stings ! " At this thought, rendered still more alarm- ing by the recollection of certain misadven- tures of which I had been the victim when seeking to observe too closely the combs of the Hornet (Vespa crabro), I felt a shiver of apprehension pass through my body. 68 The Primary Larva of the Shares Yet, to obtain light upon the question which brings me hither, I must needs pene- trate the fearsome swarm: I must stand for whole hours, perhaps all day, watching the works which I intend to upset; lens in hand, I must scrutinize, unmoved amid the whirl, the things that are happening in the cells. The use moreover of a mask, of gloves, of a covering of any kind is impracticable, for utter dexterity of the fingers and complete liberty of sight are essential to the investiga- tions which I have to make. No matter: even though I leave this wasps'-nest with a face swollen beyond recognition, I must to- day obtain a decisive solution of the problem which has preoccupied me too long. A few strokes of the net, aimed, beyond the limits of the swarm, at the Anthophorae on their way to the harvest or returning, soon informed me that the Sitaris-larvae are perched on the thorax, as I expected, occu- pying the same position as on the males. The circumstances therefore could not be more favourable. We will inspect the cells without further delay. My preparations are made at once : I but- ton my clothes tightly, so as to afford the Bees the least possible opportunity, and I en- ter the heart of the swarm. A few blows of 69 The Glow- Worm and Other Beetles the mattock, which arouse a far from reassur- ing crescendo in the humming of the Antho- phorae, soon place me in possession of a lump of earth; and I beat a hasty retreat, greatly astonished to find myself still safe and sound and unpursued. But the lump of earth which I have removed is from a part too near the surface; it contains nothing but Osmia-cells, which do not interest me for the moment. A second expedition is made, last- ing longer than the first; and, though my retreat is effected without great precipitation, not an Anthophora has touched me with her sting, nor even shown herself disposed to fall upon the aggressor. This success emboldens me. I remain permanently in front of the work in progress, continually removing lumps of earth filled with cells, spilling the liquid honey on the ground, eviscerating larvae and crushing the Bees busily occupied in their nests. All this devastation results merely in arousing a louder hum in the swarm and is not fol- lowed by any hostile demonstration. The Anthophorae whose cells are not hurt go about their labours as if nothing unusual were happening round about them; those whose dwellings are overturned try to repair them, or hover distractedly in front of the 70 The Primary Larva of the Sitares ruins; but none of them seems inclined to swoop down upon the author of the damage. At most, a few, more irritated than the rest, come at intervals and hover before my face, confronting me at a distance of a couple of inches, and then fly away, after a few mo- ments of this curious inspection. Despite the selection of a common site for their nests, which might suggest an attempt at communistic interests among the Antho- phoras, these Bees, therefore, obey the ego- tistical law of each one for himself and do not know how to band themselves together to repel an enemy who threatens one and all. Taken singly, the Anthophora does not even know how to dash at the enemy who is ravaging her cells and drive him away with her stings; the pacific creature hastily leaves its dwelling when disturbed by undermining and escapes in a crippled state, sometimes even mortally wounded, without thinking of making use of its venomous sting, except when it is seized and handled. Many other Hymenoptera, honey-gatherers or hunters, are quite as spiritless; and I can assert to-day, after a long experience, that only the Social Hymenoptera, the Hive-bees, the Common Wasps and the Bumble-bees, know how to devise a common defence; and only they dare 7i The Glow- Worm and Other Beetles fall singly upon the aggressor, to wreak an individual vengeance. Thanks to this unexpected lack of spirit in the Mason-bee, I was able for hours to pursue my investigations at my leisure, seated on a stone in the midst of the murmuring and distracted swarm, without receiving a single sting, though I took no precautions whatever. Country-folk, happening to pass and behold- ing me seated, unperturbed, in the midst of the whirl of Bees, stopped aghast to ask me whether I had bewitched them, whether I charmed them, since I appeared to have nothing to fear from them: " Me, moun bel ami, li-z-ave doun escoun- jurado que vous pougnioun pas, caneu de sort!" My miscellaneous impedimenta spread over the ground, boxes, glass jars and tubes, tweezers and magnifying-glasses, were cer- tainly regarded by these good people as the implements of my wizardry. We will now proceed to examine the cells. Some are still open and contain only a more or less complete store of honey. Others are hermetically sealed with an earthen lid. The contents of these latter vary greatly. Sometimes we find the larva of a Bee which has finished its mess or is on the point of 72 The Primary Larva of the Shares finishing it; sometimes a larva, white like the first, but more corpulent and of a different shape; at other times honey with' an egg floating on the surface. The honey is liquid and sticky, with a brownish colour and a very strong, repulsive smell. The egg is of a beautiful white, cylindrical in shape, slightly curved into an arc, a fifth or a sixth of an inch in length and not quite a twenty-fifth of an inch in thickness ; it is the egg of the An- thophora. In a few cells this egg is floating all alone on the surface of the honey; in others, very numerous these, we see, lying on the egg of the Anthophora, as on a sort of raft, a young Sitaris-grub with the shape and the dimen- sions which I have described above, that is to say, with the shape and the dimensions which the creature possesses on leaving the egg. This is the enemy within the gates. When and how did it get in? In none of the cells where I have observed it was I able to distinguish a fissure which could have al- lowed it to enter; they are all sealed in a quite irreproachable manner. The parasite therefore established itself in the honey- warehouse before the warehouse was closed; on the other hand, the open cells, full of honey, but as yet without the egg of the 73 The Glow- Worm and Other Beetles Anthophora, are always free from parasites. It is therefore during the laying, or after- wards, when the Anthophora is occupied in plastering the door of the cell, that the young larva gains admittance. It is impossible to decide by experiment to which of these two periods we must ascribe the introduction of the Sitares into the cell; for, however peace- able the Anthophora may be, it is evident that we cannot hope to witness what happens in the cell at the moment when she is laying an egg or at the moment when she is making the lid. But a few attempts will soon con- vince us that the only second which would allow the Sitaris to establish itself in the home of the Bee is the very second when the egg is laid on the surface of the honey. Let us take an Anthophora-cell full of honey and furnished with an egg and, after removing the lid, place it in a glass tube with a few Sitaris-grubs. The grubs do not ap- pear at all eager for this wealth of nectar placed within their reach; they wander at ran- dom about the tube, run about the outside of the cell, sometimes happen upon the edge of the orifice and very rarely venture inside. When they do, they do not go far in and they come out again at once. If one happens to reach the honey, which only half fills the 74 The Primary Larva of the Shares cell, it tries to escape as soon as it has per- ceived the shifting nature of the sticky soil upon which it was about to enter; but, totter- ing at every step, because of the viscous matter clinging to its feet, it often ends by falling back into the honey, where it dies of suffocation. Again, we may experiment as follows: having prepared a cell as before, we place a larva most carefully on its inner wall, or else on the surface of the food itself. In the first case, the larva hastens to leave the cell; in the second case, it struggles awhile on the surface of the honey and ends by getting so completely caught that, after a thousand efforts to gain the shore, it is swal- lowed up in the viscous lake. In short, all attempts to establish the Sitaris-grub in an Anthophora-cell provi- sioned with honey and furnished with an egg are no more successful than those which I made with cells whose store of food had already been broached by the larva of the Bee, as described above. It is therefore cer- tain that the Sitaris-grub does not leave the fleece of the Mason-bee when the Bee is in her cell or at the entrance to it, in order itself to make a rush for the coveted honey; for this honey would inevitably cause its 75 The Glow- Worm and Other Beetles death, if it happened by accident to touch the perilous surface merely with the tip of its tarsi. Since we cannot admit that the Sitaris-grub leaves the furry corselet of its hostess to slip unseen into the cell, whose orifice is not yet wholly walled up, at the moment when the Anthophora is building her door, all that remains to investigate is the second at which the egg is being laid. Remember in the first place that the young Sitaris which we find in a closed cell is always placed on the egg of the Bee. We shall see in a minute that this egg not merely serves as a raft for the tiny creature floating on a very treacherous lake, but also constitutes the first and indispensable part of its diet. To get at this egg, situated in the centre of the lake of honey, to reach, at all costs, this raft, which is also its first ration, the young larva evidently possesses some means of avoiding the fatal contact of the honey; and this means can be provided only by the actions of the Bee herself. In the second place, observations repeated ad nauseam have shown me that at no pe- riod do we find in each invaded cell more than a single Sitaris, in one or other of the forms which it successively assumes. Yet there are several young larvae established in 76 The Primary Larva of the Sitares the silky tangle of the Bee's thorax, all eagerly watching for the propitious moment at which to enter the dwelling in which they are to continue their development. How then does it happen that these larvae, goaded by such an appetite as one would expect after seven or eight months' complete abstinence, instead of all rushing together into the first cell within reach, on the contrary enter the various cells which the Bee is provisioning one at a time and in perfect order? Some action must take place here independent of the Sitares. To satisfy those two indispensable condi- tions, the arrival of the larva upon the egg without crossing the honey and the introduc- tion of a single larva among all those waiting in the fleece of the Bee, there can be only one explanation, which is to suppose that, at the moment when the Anthophora's egg is half out of the oviduct, one of the Sitares which have hastened from the thorax to the tip of the abdomen, one more highly fa- voured by its position, instantly settles upon the egg, a bridge too narrow for two, and with it reaches the surface of the honey. The impossibility of otherwise fulfilling the two conditions which I have stated gives to the explanation which I am offering a degree 77 The Glow-Worm and Other Beetles of certainty almost equivalent to that which would be furnished by direct observation, which is here, unfortunately, impracticable. This presupposes, it is true, in the microscopic little creature destined to live in a place where so many dangers threaten it from the first, an astonishingly rational inspiration, which adapts the means to the end with amazing logic. But is not this the invariable conclusion to which the study of instinct always leads us? When dropping her egg upon the honey, therefore, the Anthophora at the same time deposits in her cell the mortal enemy of her race; she carefully plasters the lid which closes the entrance to the cell; and all is done. A second cell is built beside it, pro- bably to suffer the same fatal doom; and so on until the more or less numerous parasites sheltered by her down are all accommodated. Let us leave the unhappy mother to continue her fruitless task and turn our attention to the young larva which has so adroitly se- cured itself board and lodging. In opening cells whose lid is still moist, we end by discovering one in which the egg, re- cently laid, supports a young Sitaris. This egg is intact and in irreproachable condition. But now the work of devastation begins : the 78 The Primary Larva of the Sitares larva, a tiny black speck which we see run- ning over the white surface of the egg, at last stops and balances itself firmly on its six legs; then, seizing the delicate skin of the egg with the sharp hooks of its mandibles, it tugs at it violently until it breaks, spilling its contents, which the larva eagerly drinks up. Thus the first stroke of the mandibles which the parasite delivers in the usurped cell is aimed at the destruction of the Bee's egg. A highly logical precaution! The Sitaris- larva, as we shall see, has to feed upon the honey in the cell ; the Anthophora-larva which would proceed from that egg would require the same food; but the portion is too small for two; so, quick, a bite at the egg and the difficulty will be removed. The story of these facts calls for no comment. This destruction of the cumbersome egg is all the more inevitable inasmuch as special tastes compel the young Sitaris-grub to make its first meals of it. Indeed we see the tiny creature begin by greedily drinking the juices which the torn wrapper of the egg allows to escape; and for several days it may be ob- served, at one time motionless on this en- velope, in which it rummages at intervals with its head, at others running over it from end to end to rip it open still wider and to 79 The Glow-Worm and Other Beetles cause a little of the juices, which become daily less abundant, to trickle from it; but we never catch it imbibing the honey which sur- rounds it on every side. For that matter, it is easy to convince ourselves that the egg combines with the function of a life-buoy that of the first ration. I have laid on the surface of the honey in a cell a tiny strip of paper, of the same dimen- sions as the egg; and on this raft I have placed a Sitaris-larva. Despite every care, my attempts, many times repeated, always failed. The larva, placed in a paper boat in the centre of the mass of honey, behaves as in the earlier experiments. Not finding what suits it, it tries to escape and perishes in the sticky toils as soon as it leaves the strip of paper, which it soon does. On the other hand, we can easily rear Sitaris-grubs by taking Anthophora-cells not invaded by the parasites, cells in which the egg is not yet hatched. All that we have to do is to pick up one of these grubs with the moistened tip of a needle and to lay it delicately on the egg. There is then no longer the least attempt to escape. After exploring the egg to find its way about, the larva rips it open and for several days does The Primary Larva of the Sitares not stir from the spot. Henceforth its de- velopment takes place unhindered, provided that the cell be protected from too rapid evaporation, which would dry up the honey and render it unfit for the grub's food. The Anthophora's egg therefore is absolutely ne- cessary to the Sitaris-larva, not merely as a boat, but also as its first nourishment. This is the whole secret, for lack of knowing which I had hitherto failed in my attempts to rear the larvae hatched in my glass jars. At the end of a week, the egg, drained by the parasite, is nothing but a dry skin. The first meal is finished. The Sitaris-larva, whose dimensions have almost doubled, now splits open along the back; and through a slit which comprises the head and the three thoracic segments a white corpusculum, the second form of this singular organism, es- capes to fall on the surface of the honey, while the aband-oned slough remains clinging to the raft which has hitherto safeguarded and fed the larva. Presently both sloughs, those of the Sitaris and the egg, will dis- appear, submerged under the waves of honey which the new larva is about to raise. Here ends the history of the first form adopted by the Sitaris. 81 The Glow-Worm and Other Beetles In summing up the above, we see that the strange little creature awaits, without food, for seven months, the appearance of the Anthophorae and at last fastens on to the hairs on the corselet of the males, who are the first to emerge and who inevitably pass within its reach in going through their cor- ridors. From the fleece of the male the larva moves, three or four weeks later, to that of the female, at the moment of coupling; and then from the female to the egg leaving the oviduct. It is by this con- catenation of complex manoeuvres that the larva in the end finds itself perched upon an egg in the middle of a closed cell filled with honey. These perilous gymnastics on the hair of a Bee in movement all the day, this passing from one sex to the other, this ar- rival in the middle of the cell by way of the egg, a dangerous bridge thrown across the sticky abyss, all this necessitates the balancing- appliances with which it is provided and which I have described above. Lastly, the destruction of the egg calls, in its turn, for a sharp pair of scissors; and such is the object of the keen, curved mandibles. Thus the primary form of the Sitares has as its func- tion to get itself carried by the Anthophora into the cell and to rip up her egg. This 82 The Primary Larva of the Sitares done, the organism becomes transformed to such a degree that repeated observations are required to make us believe the evidence of our eyes. CHAPTER IV THE PRIMARY LARVA OF THE OIL-BEETLES I INTERRUPT the history of the Sitares to speak of the Meloes, those uncouth Beetles, with their clumsy belly and their limp wing-cases yawning over their back like the tails of a fat man's coat that is far too tight for its wearer. The insect is ugly in colouring, which is black, with an occasional blue gleam, and uglier still in shape and gait; and its disgusting method of defence increases the repugnance with which it inspires us. If it judges itself to be in danger, the Meloe resorts to spontaneous bleeding. From its joints a yellowish, oily fluid oozes, which stains your fingers and makes them stink. This is the creature's blood. The English, because of its trick of discharging oily blood when on the defensive, call this insect the Oil-beetle. It would not be a particularly interesting Beetle save for its metamorphoses and the peregrinations of its larva, which are similar in every respect to those of the larva of the Sitares. In their first form, the Oil- beetles are parasites of the Anthophorae; 84 The Primary Larva of the Oil-Beetles their tiny grub, when it leaves the egg, has itself carried into the cell by the Bee whose victuals are to form its food. Observed in the down of various Bees, the queer little creature for a long time baffled the sagacity of the naturalists, who, mistaking its true origin, made it a species of a special family of wingless insects. It was the Bee- louse (Pediculis apis) of Linnaeus; 1 the Tri- ungulin of the Andrenae (Triungulinus An- drenetarum] of Leon Dufour. They saw in it a parasite, a sort of Louse, living in the fleece of the honey-gatherers. It was re- served for the distinguished English na- turalist Newport to show that this supposed Louse was the first state of the Oil-beetles. Some observations of my own will fill a few lacunae in the English scientist's monograph. I will therefore sketch the evolution of the Oil-beetles, using Newport's work where my own observations are defective. In this way the Sitares and the Meloes, alike in habits and transformations, will be compared; and the comparison will throw a certain light upon the strange metamorphoses of these insects. 1 Carolus Linnaeus (Karl von Linne, 1707-1778), the cel- ebrated Swedish botanist and naturalist, founder of the Linnaean system of classification. — Translator's Note. 85 The Glow- Worm and Other Beetles The same Mason-bee (Anthophora pili- pes) upon whom the Sitares live also feeds a few scarce Meloes (M. cicatricosus} in its cells. A second Anthophora of my district (A. parietina] is more subject to this para- site's invasions. It was also in the nests of an Anthophora, but of a different species (A. retusa], that Newport observed the same Oil-beetle. These three lodgings adopted by Meloe cicatricosus may be of some slight interest, as leading us to suspect that each species of Meloe is apparently the parasite of diverse Bees, a suspicion which will be confirmed when we examine the man- ner in which the larvae reach the cell full of honey. The Sitares, though less given to change of lodging, are likewise able to in- habit nests of different species. They are very common in the cells of Anthophora pilipes; but I have found them also, in very small numbers, it is true, in the cells of A. personata. Despite the presence of Meloe cicatricosus in the dwellings of the Mason-bee, which I so often ransacked in compiling the history of the Sitares, I never saw this insect, at any season of the year, wandering on the per- pendicular soil, at the entrance of the corri- dors, for the purpose of laying its eggs The Primary Larva of the Oil-Beetles there, as the Sitares do; and I should know nothing of the details of the egg-laying if Godart,1 de Geer 2 and, above all, Newport had not informed us that the Oil-beetles lay their eggs in the earth. According to the last-named author, the various Oil-beetles whom he had the opportunity of observing dig, among the roots of a clump of grass, in a dry soil exposed to the sun, a hole a couple of inches deep which they carefully fill up after laying their eggs there in a heap. This laying is repeated three or four times over, at intervals of a few days during the same season. For each batch of eggs the female digs a special hole, which she does not fail to fill up afterwards. This takes place in April and May. The number of eggs laid in a single batch is really prodigious. In the first batch, which, it is true, is the most prolific of all, Meloe pros car abaus, according to New- port's calculations, produces the astonishing number of 4,218 eggs, which is double the number of eggs laid by a Sitaris. And what 1 Jean Baptiste Godart (1775-1823), the principal editor of L'Histoire naturelle des lepidopteres de France. — Translator's Note. 2 Baron Karl de Geer (1720-1778), the Swedish ento- mologist, author of Memoires pour servir a I'histoire des insectes (1752-1778). — Translator's Note. The Glow-Worm and Other Beetles must the number be, when we allow for the two or three batches that follow the first! The Sitares, entrusting their eggs to the very corridors through which the Anthophora is bound to pass, spare their larvae a host of dangers which the larvae of the Meloe have to run, for these, born far from the dwell- ings of the Bees, are obliged to make their own way to their hymenopterous foster- parents. The Oil-beetles, therefore, lack- ing the instinct of the Sitares, are endowed with incomparably greater fecundity. The richness of their ovaries atones for the in- sufficiency of instinct by proportioning the number of germs in accordance with the risks of destruction. What transcendent harmony is this, which thus holds the scales between the fecundity of the ovaries and the perfect- ion of instinct! The hatching of the eggs takes place at the end of May or in June, about a month after they are laid. The eggs of the Sitares also are hatched after the same lapse of time. But the Meloe-larvae, more greatly fa- voured, are able to set off immediately in search of the Bees that are to feed them; while those of the Sitares, hatched in Sep- tember, have to wait motionless and in com- plete abstinence for the emergence of the An- The Primary Larva of the Oil-Beetles thophorae the entrance to whose cells they guard. I will not describe the young Meloe- larva, which is sufficiently well known, in particular by the description and the diagram furnished by Newport. To enable the reader to understand what follows, I will confine myself to stating that this primary larva is a sort of little yellow louse, long and slender, found in the spring in the down of different Bees. How has this tiny creature made its way from the underground lodging where the eggs are hatched to the fleece of a Bee? New- port suspects that the young Oil-beetles, on emerging from their natal burrow, climb upon the neighbouring plants, especially upon the Cichoriceae, and wait, concealed among the petals, until a few Bees chance to plunder the flower, when they promptly fasten on to their fur and allow themselves to be borne away by them. I have more than Newport's suspicions upon this curious point; my per- sonal observations and experiments are ab- solutely convincing. I will relate them as the first phase of the history of the Bee- louse. They date back to the 2jrd of May, 1858. A vertical bank on the road from Car- pentras to Bedoin is this time the scene of The Glow- Worm and Other Beetles my observations. This bank, baked by the sun, is exploited by numerous swarms of Anthophoras, who, more industrious than their congeners, are in the habit of building, at the entrance to their corridors, with serp- entine fillets of earth, a vestibule, a defensive bastion in the form of an arched cylinder. In a word, they are swarms of A. parietina. A sparse carpet of turf extends from the edge of the road to the foot of the bank. The more confortably to follow the work of the Bees, in the hope of wresting some secret from them, I had been lying for a few moments upon this turf, in the very heart of the inoffensive swarm, when my clothes were invaded by legions of little yellow lice, run- ning with desperate eagerness through the hairy thickets of the nap of the cloth. In these tiny creatures, with which I was pow- dered here and there as with yellow dust, I soon recognized an old acquaintance, the young Oil-beetles, whom I now saw for the first time elsewhere than in the Bees' fur or the interior of their cells. I could not lose so excellent an opportunity of learning how these larvae manage to establish themselves upon the bodies of their foster-parents. In the grass where, after lying down for a moment, I had caught these lice were a 90 The Primary Larva of the Oil-Beetles few plants in blossom, of which the most abundant were three composites : Hedypnois polymorpha, Senecio gallicus and Anthemis arvensis. Now it was on a composite, a dandelion, that Newport seemed to remem- ber seeing some young Oil-beetles; and my attention therefore was first of all directed to the plants which I have named. To my great satisfaction, nearly all the flowers of these three plants, especially those of the camomile (Anthemis) were occupied by young Oil-beetles in greater or lesser num- bers. On one head of camormle I counted forty of these tiny insects, cowering motion- less in the centre of the florets. On the other hand, I could not discover any on the flowers of the poppy or of a wild rocket (Diplotaxis muralis) which grew promiscuously among the plants aforesaid. It seems to me, there- fore, that it is only on the composite flowers that the Meloe-larvae await the Bees' ar- rival. In addition to this population encamped upon the heads of the composites and re- maining motionless, as though it had achieved its object for the moment, I soon discovered yet another, far more numerous, whose anx- ious activity betrayed a fruitless search. On the ground, in the grass, numberless little 91 The Glow-Worm and Other Beetles larvae were running in a great flutter, re- calling in some respects the tumultuous dis- order of an overturned Ant-hill; others were hurriedly climbing to the tip of a blade of grass and descending with the same haste; others again were plunging into the downy fluff of the withered everlastings, remaining there a moment and quickly reappearing to continue their search. Lastly, with a little attention, I was able to convince myself that within an area of a dozen square yards there was perhaps not a single blade of grass which was not explored by several of these larvae. I was evidently witnessing the recent emergence of the young Oil-beetles from their maternal lairs. Part of them had already settled on the groundsel- and camomile- flowers to await the 'arrival of the Bees; but the majority were still wandering in search of this provisional refuge. It was by this wandering population that I had been in- vaded when I lay down at the foot of the bank. It was impossible that all these larvae, the tale of whose alarming thousands I would not venture to define, should form one family and recognize a common mother; despite what Newport has told us of the Oil-beetles' astonishing fecundity, I could not believe this, so great was their multitude. 92 The Primary Larva of the Oil-Beetles Though the green carpet was continued for a considerable distance along the side of the road, I could not detect a single Meloe- larva elsewhere than in the few square yards lying in front of the bank inhabited by the Mason-bee. These larvae therefore could not have come far; to find themselves near the Anthophorae they had had no long pil- grimage to make, for there was not a sign of the inevitable stragglers and laggards that follow in the wake of a travelling caravan. The burrows in which the eggs were hatched were therefore in that turf opposite the Bees' abode. Thus the Oil-beetles, far from laying their eggs at random, as their wander- ing life might lead one to suppose, and leav- ing their young to the task of approaching their future home, are able to recognize the spots haunted by the Anthophorae and lay their eggs in the near neighbourhood of those spots. With such a multitude of parasites occu- pying the composite flowers in close proximity to the Anthophora's nests, it is impossible that the majority of the swarm should not become infested sooner or later. At the time of my observations, a comparatively tiny proportion of the starving legion was waiting on the flowers; the others were still 93 The Glow-Worm and Other Beetles wandering on the ground, where the Antho- phorae very rarely alight; and yet I detected the presence of several Meloe-larvae in the thoracic down of nearly all the Anthophorae which I caught and examined. I have also found them on the bodies of the Melecta- and Coelioxys-bees,1 who are parasitic on the Anthophorae. Suspending their audacious . patrolling before the gal- leries under construction, these spoilers of the victualled cells alight for an instant on a camomile-flower and lo, the thief is robbed! A tiny, imperceptible louse has slipped into the thick of the downy fur and, at the moment when the parasite, after de- stroying the Anthophora's egg, is laying her own upon the stolen honey, will creep upon this egg, destroy it in its turn and remain sole mistress of the provisions. The mess of honey amassed by the Anthophora will thus pass through the hands of three owners and remain finally the property of the weak- est of the three. And who shall say whether the Meloe, in its turn, will not be dispossessed by a fresh thief; or even whether it will not, in the state of a drowsy, fat and flabby larva, fall a 1 Cf. The Mason-bees: chaps, viii. and ix. — Trans- lator's Note. 94 The Primary Larva of the Oil-Beetles prey to some marauder who will munch its live entrails? As we meditate upon this deadly, implacable struggle which nature im- poses, for their preservation, on these differ- ent creatures, which are by turns possessors and dispossessed, devourers and devoured, a painful impression mingles with the wonder aroused by the means employed by each parasite to attain its end ; and, forgetting for a moment the tiny world in which these things happen, we are seized with terror at this concatenation of larceny, cunning and bri- gandage which forms part, alas, of the de- signs of alma parens rerumf The young Meloe-larvas established in the down of the Anthophorae or in that of the Melecta- and the Coelioxys-bees, their para- sites, had adopted an infallible means of sooner or later reaching the desired cell. Was it, so far as they were concerned, a choice dictated by the foresight of instinct, or just simply the result of a lucky chance? The question was soon decided. Various Flies — Drone-flies and Bluebottles (Eris- talis tenax and Calliphora vomitoria} — would settle from time to time on the ground- sel- or camomile-flowers occupied by the young Meloes and stop for a moment to suck the sweet secretions. On all these Flies, 95 The Glow- Worm and Other Beetles with very few exceptions, I found Meloe- larvse, motionless in the silky down of the thorax. I may also mention, as infested by these larvae, an Ammophila (A. hirsuta) ,* who victuals her burrows with a caterpillar in early spring, while her kinswomen build their nests in autumn. This Wasp merely grazes, so to speak, the surface of a flower; I catch her; there are Meloes moving about her body. It is clear that neither the Drone- flies nor the Bluebottles, whose larvae live in putrefying matter, nor yet the Ammophilae who victual theirs with caterpillars, could ever have carried the larvae which invaded them into cells filled with honey. These larvae therefore had gone astray; and in- stinct, as does not often happen, was here at fault. Let us now turn our attention to the young Meloes waiting expectant upon the camomile- flowers. There they are, ten, fifteen or more, lodged half-way down the florets of a single blossom or in their interstices; it therefore needs a certain degree of scrutiny to perceive them, their hiding-place being the 1 For the Wasp known as the Hairy Ammophila, who feeds her young on the Grey Worm, the caterpillar of the Turnip Moth, cf. The Hunting Wasps, chaps, xviii. to JDC. — Translator's Note. 96 The Primary Larva of the Oil-Beetles more effectual in that the amber colour of their bodies merges in the yellow hue of the florets. So long as nothing unusual happens upon the flower, so long as no sudden shock announces the arrival of a strange visitor, the Meloes remain absolutely motionless and give no sign of life. To see them dipping vertically, head downwards, into the florets, one might suppose that they were seeking some sweet liquid, their food; but in that case they ought to pass more frequently from one floret to another, which they do not, except when, after a false alarm, they regain their hiding-places and choose the spot which seems to them the most favourable. This immo- bility means that the florets of the camomile serve them only as a place of ambush, even as later the Anthophora's body will serve them solely as a vehicle to convey them to the Bee's cell. They take no nourishment, either on the flowers or on the Bees; and, as with the Sitares, their first meal will con- sist of the Anthophora's egg, which the hooks of their mandibles are intended to rip open. Their immobility is, as we have said, com- plete; but nothing is easier than to arouse their suspended activity. Shake a camomile- blossom lightly with a bit of straw : instantly the Meloes leave their hiding-places, come 97 The Glow-Worm and Other Beetles up and scatter in all directions on the white petals of the circumference, running over them from one end to the other with all the speed which the smallness of their size per- mits. On reaching the extreme end of the petals, they fasten to it either with their caudal appendages, or perhaps with a sticky substance similar to that furnished by the anal button of the Sitares; and, with their bodies hanging outside and their six legs free, they bend about in every direction and stretch as far out as they can, as though striving to touch an object out of their reach. If nothing offers for them to seize upon, after a few vain attempts they regain the centre of the flower and soon resume their immobility. But, if we place near them any object whatever, they do not fail to catch on to it with surprising agility. A blade of grass, a bit of straw, the handle of my tweezers which I hold out to them: they accept any- thing in their eagerness to quit the provisional shelter of the flower. It is true that, after finding themselves on these inanimate ob- jects, they soon recognize that they have gone astray, as we see by their bustling move- ments to and fro and their tendency to go back to the flower if there still be time. The Primary Larva of the Oil-Beetles Those which have thus giddily flung them- selves upon a bit of straw and are allowed to return to their flower do not readily fall a second time into the same trap. There is therefore, in these animated specks, a memory, an experience of things. After these experiments I tried others with hairy materials imitating more or less closely the down of the Bees, with little pieces of cloth or velvet cut from my clothes, with plugs of cotton wool, with pellets of flock gathered from the everlastings. Upon all these objects, offered with the tweezers, the Meloes flung themselves without any diffi- culty; but, instead of keeping quiet, as they do on the bodies of the Bees, they soon con- vinced me, by their restless behaviour, that they found themselves as much out of their element on these furry materials as on the smooth surface of a bit of straw. I ought to have expected this : had I not just seen them wandering without pause upon the everlast- ings enveloped with cottony flock? If reaching the shelter of a downy surface were enough to make them believe themselves safe in harbour, nearly all would perish, without further attempts, in the down of the plants. Let us now offer them live insects and, first of all, Anthophorae. If the Bee, after we 99 The Glow- Worm and Other Beetles have rid her of the parasites which she may be carrying, be taken by the wings and held for a moment in contact with the flower, we invariably find her, after this rapid contact, overrun by Meloes clinging to her hairs. The larvae nimbly take up their position on the thorax, usually on the shoulders or sides, and once there they remain motionless : the second stage of their strange journey is com- passed. After the Anthophorae, I tried the first live insects that I was able to procure at once : Drone-flies, Bluebottles, Hive-bees, small Butterflies. All were alike overrun by the Meloes, without hesitation. What is more, there was no attempt made to return to the flowers. As I could not find any Beetles at the moment, I was unable to experiment with them. Newport, experimenting, it is true, under conditions very different from mine, since his observations related to young Meloes held captive in a glass jar, while mine were made in the normal circumstances, Newport, I was saying, saw Meloes fasten to the body of a Malachius and stay there without moving, which inclines me to believe that with Beetles I should have obtained the same results as, for instance, with a Drone- fly. And I did, in fact, at a later date, find The Primary Larva of the Oil-Beetles some Meloe-larvae on the body of a big Beetle, the Golden Rose-chafer (Cetonia aurata) , an assiduous visitor of the flowers. After exhausting the insect class, I put within their reach my last resource, a large black Spider. Without hesitation they passed from the flower to the arachnid, made for places near the joints of the legs and settled there without moving. Every- thing therefore seems to suit their plans for leaving the provisional abode where they are waiting; without distinction of species, genus, or class, they fasten to the first living crea- ture that chance brings within their reach. We now understand how it is that these young larvae have been observed upon a host of different insects and especially upon the early Flies and Bees pillaging the flowers; we can also understand the need for that prodigious number of eggs laid by a single Oil-beetle, since the vast majority of the larvae which come out of them will infallibly go astray and will not succeed in reaching the cells of the Anthophorae. Instinct is at fault here; and fecundity makes up for it. But instinct recovers its infallibility in an- other case. The Meloes, as we have seen, pass without difficulty from the flower to the objects within their reach, whatever these 101 The Glow- Worm and Other Beetles may be, smooth or hairy, living or inanimate. This done, they behave very differently, ac- cording as they have chanced to invade the body of an insect or some other object. In the first case, on a downy Fly or Butterfly, on a smooth-skinned Spider or Beetle, the larvae remain motionless after reaching the point which suits them. Their instinctive desire is therefore satisfied. In the second case, in the midst of the nap of cloth or vel- vet, or the filaments of cotton, or the flock of the everlasting, or, lastly, on the smooth surface of a leaf or a straw, they betray the knowledge of their mistake by their continual coming and going, by their efforts to return to the flower imprudently abandoned. How then do they recognize the nature of the object to which they have just moved? How is it that this object, whatever the qua- lity of its surface, will sometimes suit them and sometimes not? Do they judge their new lodging by sight? But then no mistake would be possible ; the sense of sight would tell them at the outset whether the object within reach was suitable or not; and emigra- tion would or would not take place accord- ing to its decision. And then how can we suppose that, buried in the dense thicket of a pellet of cotton-wool or in the fleece of an The Primary Larva of the Oil-Beetles Anthophora, the imperceptible larva can recognize, by sight, the enormous mass which it is perambulating? Is it by touch, by some sensation due to the inner vibrations of living flesh? Not so, for the Meloes remain motionless on insect corpses that have dried up completely, on dead Anthophorae taken from cells at least a year old. I have seen them keep abso- lutely quiet on fragments of an Anthophora on a thorax long since nibbled and emptied by the Mites. By what sense then can they distinguish the thorax of an Anthophora from a velvety pellet, when sight and touch are out of the question? The sense of smell remains. But in that case what exquisite subtlety must we not take for granted? Moreover, what similarity of smell can we admit between all the insects which, dead or alive, whole or in pieces, fresh or dried, suit the Meloes, while anything else does not suit them? A wretched louse, a living speck, leaves us mightily perplexed as to the sensibility which directs it. Here is yet one more riddle added to all the others. After the observations which I have de- scribed, it remained for me to search the earthen surface inhabited by the Antho- phorse: I should then have followed the 103 The Glow- Worm and Other Beetles Meloe-larva in its transformations. It was certainly cicatricosus whose larvae I had been studying; it was certainly this insect which ravaged the cells of the Mason-bee, for I found it dead in the old galleries which it had been unable to leave. This oppor- tunity, which did not occur again, promised me an ample harvest. I had to give it all up. My Thursday was drawing to a close ; I had to return to Avignon, to resume my lessons on the electrophorus and the Tori- cellian tube. O happy Thursdays! What glorious opportunities I lost because you were too short! We will go back a year to continue this history. I collected, under far less favour- able conditions, it is true, enough notes to map out the biography of the tiny creature which we have just seen migrating from the camomile-flowers to the Anthophora's back. From what I have said of the Sitaris-larvae, it is plain that the Meloe-larvae perched, like the former, on the back of a Bee, have but one aim : to get themselves conveyed by this Bee to the victualled cells. Their object is not to live for a time on the body that carries them. Were it necessary to prove this, it would be enough to say that we never see these 104 The Primary Larva of the Oil-Beetles larvae attempt to pierce the skin of the Bee, or else to nibble at a hair or two, nor do we see them increase in size so long as they are on the Bee's body. To the Meloes, as to the Sitares, the Anthophora serves merely as a vehicle which conveys them to their goal, the victualled cell. It remains for us to learn how the Meloe leaves the down of the Bee which has carried it, in order to enter the cell. With larvae collected from the bodies of different Bees, before I was fully acquainted with the tactics of the Sitares, I undertook, as Newport had done before me, certain investigations in- tended to throw light on this leading point in the Oil-beetle's history. My attempts, based upon those which I had made with the Sitares, resulted in the same failure. The tiny creatures, when brought into contact with Anthophora-larvae or -nymphs, paid no attention whatever to their prey; others, placed near cells which were open and full of honey, did not enter them, or at most ven- tured to the edge of the orifice ; others, lastly, put inside the cell, on the dry wall or on the surface of the honey, came out again im- mediately or else got stuck and died. The touch of the honey is as fatal to them as to the young Sitares. 105 The Glow-Worm and Other Beetles Searches made at various periods in the nests of the Hairy-footed Anthophora had taught me some years earlier that Meloe cicatricosus, like the Sitares, is a parasite of that Bee; indeed I had at different times dis- covered adult Meloes, dead and shrivelled, in the Bee's cells. On the other hand, I knew from Leon Dufour that the little yellow animal, the Louse found in the Bee's down, had been recognized, thanks to Newport's investigations, as the larva of the Oil-beetle. With these data, rendered still more striking by what I was learning daily on the subject of the Sitares, I went to Carpentras, on the 2ist of May, to inspect the nests of the Anthophorae, then building, as I have described. Though I was almost certain of succeeding, sooner or later, with the Sitares, who were ex- cessively abundant, I had very little hope of the Meloes, which on the contrary are very scarce in the same nests. Circum- stances, however, favoured me more than I dared hope and, after six hours' labour, in which the pick played a great part, I be- came the possessor, by the sweat of my brow, of a considerable number of cells occupied by Sitares and two other cells appropriated by Meloes. 106 The Primary Larva of the Oil-Beetles While my enthusiasm had not had time to cool at the sight, momentarily repeated, of a young Sitaris perched upon an Antho- phora's egg floating in the centre of the little pool of honey, it might well have burst all restraints on beholding the contents of one of these cells. On the black, liquid honey a wrinkled pellicle is floating; and on this pelli- cle, motionless, is a yellow louse. The pelli- cle is the empty envelope of the Anthophora's egg; the louse is a Meloe-larva. The story of this larva becomes self-evi- dent. The young Meloe leaves the down of the Bee at the moment when the egg is laid; and, since contact with the honey would be fatal to the grub, it must, in order to save itself, adopt the tactics followed by the Sitaris, that is to say, it must allow itself to drop on the surface of the honey with the egg which is in the act of being laid. There, its first task is to devour the egg which serves it for a raft, as is attested by the empty envelope on which it still remains; and it is after this -meal, the only one that it takes so long as it retains its present form, that it must commence its long series of transfor- mations and feed upon the honey amassed by the Anthophora. This was the reason of the complete failure both of my attempts 107 The, Glow- Worm and Other Beetles. and of Newport's to rear the young Meloe- larvae. Instead of offering them honey, or larvae, or nymphs, we should have placed them on the eggs recently laid by the Antho- phora. On my return from Carpentras, I meant to try this method, together with that of the Sitares, with which I had been so successful; but, as I had no M doe-larvae at my disposal and could not obtain any save by searching for them in the Bees' fleece, the Anthophora- eggs were all discovered to have hatched in the cells which I brought back from my ex- pedition, when I was at last able to find some. This lost experiment is little to be regretted, for, since the Meloes and the Sitares ex- hibiting the completest similarity not only in habits but also in their method of evolution, there is no doubt whatever that I should have succeeded. I even believe that this method may be attempted with the cells of various Bees, provided that the eggs and the honey do not differ too greatly from the Antho- phora's. I should not, for example, count on being successful with the cells of the three-horned Osmia, who shares the Antho- phora's quarters: her egg is short and thick; and her honey is yellow, odourless, solid, al- most a powder and very faintly flavoured. 1 08 CHAPTER V HYPERMETAMORPHOSIS "DY a Machiavellian stratagem the pri- *-* mary larva of the Oil-beetle or the Sitaris has penetrated the Anthophora's cell; it has settled on the egg, which is its first food and its life-raft in one. What becomes of it once the egg is exhausted? Let us, to begin with, go back to the larva of the Sitaris. By the end of a week the Anthophora's egg has been drained dry by the parasite and is reduced to the envelope, a shallow skiff which preserves the tiny creature from the deadly contact of the honey. It is on this skiff that the first trans- formation takes place, whereafter the larva, which is now organized to live in a glutinous environment, drops off the raft into the pool of honey and leaves its empty skin, split along the back, clinging to the pellicle of the egg. At this stage we see floating motion- less on the honey a milk-white atom, oval, flat and a twelfth of an inch long. This is the larva of the Sitaris in its new form. With the aid of a lens we can distinguish the 109 The Glow-Worm and Other Beetles fluctuations of the digestive canal, which is gorging itself with honey; and along the cir- cumference of the flat, elliptical back we per- ceive a double row of breathing-pores which, thanks to their position, cannot be choked by the viscous liquid. Before describing the larva in detail we will wait for it to attain its full development, which cannot take long, for the provisions are rapidly diminishing. The rapidity however is not to be com- pared with that with which the gluttonous larvae of the Anthophora consume their food. Thus, on visiting the dwellings of the Anthophorae for the last time, on the 25th of June, I found that the Bee's larvae had all finished their rations and attained their full development, whereas those of the Sitares, still immersed in the honey, were, for the most part, only half the size which they must finally attain. This is yet another reason why the Sitares should destroy an egg which, were it to develop, would produce a voracious larva, capable of starving them in a very short time. When rearing the larvae myself in test-tubes, I have found that the Sitares take thirty-five to forty days to finish their mess of honey and that the larvae of the Anthophora spend less than a fort- night over the same meal. Hypermetamorphosis It is in the first half of July that the Sitaris- grubs reach their full dimensions. At this period the cell usurped by the parasite con- tains nothing beyond a full-fed larva and, in a corner, a heap of reddish droppings. This larva is soft and white, about half an inch in length and a quarter of an inch wide at its broadest part. Seen from above as it floats on the honey, it is elliptical in form, tapering gradually towards the front and more suddenly towards the rear. Its ventral surface is highly convex; its dorsal surface, on the contrary, is almost flat. When the larva is floating on the liquid honey, it is as it were steadied by the excessive development of the ventral surface immersed in the honey, which enables it to acquire an equilibrium that is of the greatest importance to its wel- fare. In fact, the breathing-holes, arranged without means of protection on either edge of the almost flat back, are level with the viscous liquid and would be choked by that sticky glue at the least false movement, if a suitably ballasted hold did not prevent the larva from heeling over. Never was corpu- lent abdomen of greater use : thanks to this plumpness of the belly the larva is protected from asphyxia. Its segments number thirteen, including The Glow- Worm and Other Beetles the head. This head is pale, soft, like the rest of the body, and very small compared with the rest of the creature. The antennae are excessively short and consist of two cylindrical joints. I have vainly looked for the eyes with a powerful magnifying-glass. In its former state, the larva, subject to strange migrations, obviously needs the sense of sight and is provided with four ocelli. In its present state, of what use would eyes be to it at the bottom of a clay cell, where the most absolute darkness prevails? The labrum is prominent, is not distinctly divided from the head, is curved in front and edged with pale and very fine bristles. The mandibles are small, reddish toward the tips, blunt and hollowed out spoonwise on the in- ner side. Below the mandibles is a fleshy part crowned with two very tiny nipples. This is the lower lip with its two palpi. It is flanked right and left by two other parts, likewise fleshy, adhering closely to the lip and bearing at the tip a rudimentary palp consisting of two or three very tiny joints. These two parts are the future jaws. All this apparatus of lips and jaws is completely immobile and in a rudimentary condition which is difficult to describe. They are bud- ding organs, still faint and embryonic. The Hypermetamorphosis labrum and the complicated lamina formed by the lip and the jaws leave between them a narrow slit in which the mandibles work. The legs are merely vestiges, for, though they consist of three tiny cylindrical joints, they are barely a fiftieth of an inch in length. The creature is unable to make use of them, not only in the liquid honey upon which it lives, but even on a solid surface. If we take the larva from the cell and place it on a hard substance, to observe it more readily, we see that the inordinate protuberance of the abdomen, by lifting the thorax from the ground, prevents the legs' from finding a support. Lying on its side, the only possible position because of its conformation, the larva remains motionless or only makes a few lazy, wriggling movements of the ab- domen, without ever stirring its feeble limbs, which for that matter could not assist it in any way. In short, the tiny creature of the first stage, so active and alert, is succeeded by a ventripotent grub, deprived of move- ment by its very obesity. Who would recog- nize in this clumsy, flabby, blind, hideously pot-bellied creature, with nothing but a sort of stumps for legs, the elegant pigmy of but a little while back, armour-clad, slender and "3. The Glow-Worm and Other Beetles provided with highly perfected organs for performing its perilous journeys? Lastly, we count nine pairs of stigmata : one pair on the mesothorax and the rest on the first eight segments of the abdomen. The last pair, that on the eighth abdominal segment, consists of stigmata so small that to detect them we have to gather their posi- tion by that in the succeeding states of the larva and to pass a very patient magnifying- glass along the direction of the other pairs. These are as yet but vestigial stigmata. The others are fairly large, with pale, round, flat edges. If in its first form the Sitaris-larva is or- ganized for action, to obtain possession of the coveted cell, in its second form it is or- ganized solely to digest the provisions ac- quired. Let us take a glance at its internal structure and in particular at its digestive apparatus. Here is a strange thing: this apparatus, in which the hoard of honey amassed by the Anthophora is to be engulfed, is similar in every respect to that of the adult Sitaris, who possibly never takes food. We find in both the same very short oesophagus, the same chylific ventricle, empty in the per- fect insect, distended in the larva with an abundant orange-coloured pulp; in both the 114 Hypermetamorphosis same gall-bladders, four in number, connected with the rectum by one of their extremities. Like the perfect insect, the larva is devoid of salivary glands or any other similar ap- paratus. Its nervous system comprises eleven ganglia, not counting the oesophageal collar, whereas in the perfect insect there are only seven : three for the thorax, of which the last two are contiguous, and four for the abdo- men. When its rations are finished the larva re- mains a few days in a motionless condition, ejecting from time to time a few reddish droppings until the digestive canal is com- pletely cleared of its orange-coloured pulp. Then the creature contracts itself, huddles it- self together; and before long* we see coming detached from its body a transparent, slightly crumpled and extremely fine pellicle, form- ing a closed bag, in which the successive trans- formations will take place henceforth. On this epidermal bag, this sort of trans- parent leather bottle, formed by the larva's skin detached all of a piece, without a slit of any kind, we can distinguish the several well-preserved external organs: the head, with its antennae, mandibles, paws and palpi; the thoracic segments, with their vestiges of legs; the abdomen, with its chain of breath- "5 The Glow- Worm and Other Beetles ing-holes still connected one to another by tracheal threads. Then beneath this pellicle, which is so deli- cate that it can hardly bear the most cautious touch, we see a soft, white mass taking shape, a mass which in a few hours acquires a firm, horny consistency and a vivid yellow hue. The transformation is now complete. Let us tear the fine gauze bag enclosing the organ- ism which has just come into being and direct our investigation to this third form of the Sitaris-larva. It is an inert, segmented body, with an oval outline, a horny consistency, just like that of puae and chrysalids, and a bright- yellow colour, which we can best describe by likening it to that of a lemon-drop. Its up- per surface forms a double inclined plane with a very blunt ridge; its lower surface is at first flat, but, as the result of evaporation, becomes more concave daily, leaving a pro- jecting rim all around its oval outline. Lastly, its two extremities or poles are slightly flattened. The major axis of the lower surface averages half an inch in length and the minor axis a quarter of an inch. At the cephalic pole of this body is a sort of mask, modelled roughly on the head of the larva, and at the opposite pole a small 116 Hypermetamorphosis circular disk deeply wrinkled at the centre. The three segments that come after the head bear each a pair of very minute knobs, hardly visible without the lens : these are, to the legs of the larva in its previous form, what the cephalic mask is to the head of the same larva. They are not organs, but indications, landmarks placed at the points where these organs will appear later. On either side we count nine stigmata, set as before on the mesothorax and the first eight abdominal segments. The first eight breathing-holes are dark brown and stand out plainly against the yellow colour of the body. They consist of small, shiny, conical knobs, perforated at the top with a round hole. The ninth stigma, though fashioned like the others, is ever so much smaller; it cannot be distin- guished without the lens. The anomaly, already so manifest in the change from the first form to the second, becomes even more so here; and we do not know what name to give to an organism without a standard of comparison, not only in the order of Beetles, but in the whole class of insects. While, on the one hand, this organism offers many points of resemblance to the pupae of the Flies in its horny con- sistency, in the complete immobility of its 117 The Glow-Worm and Other Beetles various segments, in the all but absolute ab- sence of relief which would enable one to distinguish the parts of the perfect insect; while, on the other hand, it approximates to the chrysalids, because the creature, to attain this condition, has to shed its skin, as the caterpillars do, it differs from the pupa because it has for covering not the surface skin, which has become horny, but rather one of the inner skins of the larva; and it differs from the chrysalids by the absence of mould- ings which in the latter betray the appendages of the perfect insect. Lastly, it differs yet more profoundly from the pupa and the chry- salis because from both these organisms the perfect insect springs straightway, whereas that which follows what we are considering is simply a larva like that which went before. I shall suggest, to denote this curious organ- ism, the term pseudochrysalis; and I shall reserve the names primary larva, secondary larva and tertiary larva to denote, in a couple of words, each of the three forms under which the Sitares possess all the character- istics of larvae. Although the Sitaris, on assuming the form of the pseudochrysalis, is transfigured out- wardly to the point of baffling the science of entomological phases, this is not so in- 118 Hypermetamorphosis wardly. I have at every season of the year examined the viscera of the pseudochrysa- lids, which generally remain stationary for a whole year, and I have never observed other forms among their organs than those which we find in the secondary larva. The nervous system has undergone no change. The digestive apparatus is absolutely void and, because of its emptiness, appears only as a thin cord, sunk, lost amid the adipose sacs. The stercoral intestine has more substance; its outlines are better defined. The four gall-bladders are always perfectly distinct. The adipose tissue is more abund- ant than ever: it forms by itself the whole contents of the pseudochrysalis, for in the matter of volume the insignificant threads of the nervous system and the digestive ap- paratus count for nothing. It is the reserve upon which life must draw for its future labours. A few Sitares remain hardly a month in the pseudochrysalis stage. The other phases are achieved in the course of August; and at the beginning of September the insect attains the perfect state. But as a rule the development is slower; the pseudochrysalis f?ocs through the winter; and it is not, at the earliest, until June in the second year that "9 The Glow-Worm and Other Beetles the final transformations take place. Let us pass in silence over this long period of repose, during which the Sitaris, in the form of a pseudochrysalis, slumbers at the bottom of its cell, in a sleep as lethargic as that of a germ in its egg, and come to the months of June and July in the following year, the period of what we might call a second hatch- ing. The pseudochrysalis is still enclosed in the delicate pouch formed of the skin of the secondary larva. Outside, nothing fresh has happened; but important changes have taken place inside. I have said that the pseudo- chrysalis displayed an upper surface arched like a hog's back and a lower surface at first flat and then more and more concave. The sides of the double inclined plane of the up- per or dorsal surface also share in this de- pression occasioned by the evaporation of the fluid constituents ; and a time comes when these sides are so depressed that a section of the pseudochrysalis through a plane per- pendicular to its axis would be represented by a curvilinear triangle with blunted corners and inwardly convex sides. This is the ap- pearance displayed by the pseudochrysalis during the winter and spring. But in June it has lost this withered ap- Hypermetamorphosis pearance; it represents a perfect balloon, an ellipsoid of which the sections perpendicular to the major axis are circles. Something has also come to pass of greater importance than this expansion, which may be compared with that which we obtain by blowing into a wrinkled bladder. The horny integuments of the pseudochrysalis have become de- tached from their contents, all of a piece, without a break, just as happened the year before with the skin of the secondary larva; and they thus form, a fresh vesicular enve- lope, free from any adhesion to the contents and itself enclosed in the pouch formed of the secondary larva's skin. Of these two bags without outlet, one of which is enclosed within the other, the outer is transparent, flexible, colourless and extremely delicate ; the second is brittle, almost as delicate as the first, but much less translucent because of its yellow colouring, which makes it resemble a thin flake of amber. On this second sac are found the stigmatic warts, the thoracic studs and so forth, which we rroted on the pseudochrysalis. Lastly, within its cavity we catch a glimpse of something the shape of which at once recalls to mind the secondary larva. And indeed, if we tear the double envelope The Glow- Worm and Other Beetles which protects this mystery, we recognize, not without astonishment, that we have be- fore our eyes a new larva similar to the secondary. After one of the strangest transformations, the creature has gone back to its second form. To describe the new larva is unnecessary, for it differs from the former in only a few slight details. In both there is the same head, wkh its various ap- pendages barely outlined; the same vestiges of legs, the same stumps transparent as crystal. The tertiary larva differs from the secondary only by its abdomen, which is less fat, owing to the absolute emptiness of the digestive apparatus; by a double chain of fleshy cushions extending along each side; by the rim of the stigmata, crystalline and slightly projecting, but less so than in the pseudochrysalis; by the ninth pair of breath- ing-holes, hitherto rudimentary but now al- most as large as the rest; lastly by the man- dibles ending in a very sharp point. Evicted from its twofold sheath, the tertiary larva makes only very lazy movements of con- traction and dilation, without being able to advance, without even being able to main- tain its normal position, because of the weak- ness of its legs. It usually remains motion- less, lying on its side, or else displays its Hypermetamorphosis drowsy activity merely by feeble, wormlike movements. By dint of these alternate contractions and dilations, indolent though they be, the larva nevertheless contrives to turn right round in the sort of shell with which the pseudo- chrysalidal integuments provide it, when by accident it finds itself placed head down- wards; and this operation is all the more dif- ficult inasmuch as the larva almost exactly fills the cavity of the shell. The creature contracts, bends its head under its belly and slides its front half over its hinder half by wormlike movements so slow that the lens can hardly detect them. In less than a quarter of an hour the larva, at first turned upside down, finds itself again head upper- most. I admire this gymnastic feat, but have some difficulty in understanding it, so small is the space which the larva, when at rest in its cell, leaves unoccupied, compared with that which we should be justified in ex- pecting from the possibility of such a re- versal. The larva does not long enjoy the privilege which enables it to resume inside its cell, when this is moved from its original position, the attitude which it prefers, that is to say, with its head up. Two days, at most, after its first appear- 123 The Glow- Worm and Other Beetles ance it relapses into an inertia as complete as that of the pseudochrysalis. On removing it from its amber shell, we see that its faculty of contracting or dilating at will is so com- pletely paralysed that the stimulus of a needle is unable to provoke it, though the integu- ments have retained all their flexibility and though no perceptible change has occurred in the organization. The irritability, there- fore, which in the pseudochrysalis is sus- pended for a whole year, reawakens for a moment, to relapse instantly into the deep- est torpor. This torpor will be partly dis- pelled only at the moment of the passing into the nymphal stage, to return immediately afterwards and last until the insect attains the perfect state. Further, on holding larvse of the third form, or nymphs enclosed in their cells, in an inverted position, in glass tubes, we never see them regain an erect position, however long we continue the experiment. The per- fect insect itself, during the time that it is enclosed in the shell, cannot regain it, for lack of the requisite flexibility. This total absence of movement in the tertiary larva, when a few days old, and also in the nymph, together with the smallness of the space left free in the shell, would necessarily lead to 124 Hypermetamorphosis the conviction, if we had not witnessed the first moments of the tertiary larva, that it is absolutely impossible for the creature to turn right round. And now see to what curious inferences this lack of observations made at the due moment may lead us. We collect some pseudochrysalids and heap them in a glass jar in all possible positions. The favour- able season arrives; and with very legitimate astonishment we find that, in a large num- ber of shells, the larva or nymph occupies an inverted position, that is to say, the head is turned towards the anal extremity of the shell. In vain we watch these re- versed bodies for any indications of move- ment; in vain we place the shells in every imaginable position, to see if the creature will turn round; in vain, once more, we ask our- selves where the free space is which this turning would demand. The illusion is complete : I have been taken in by it my- self; and for two years I indulged in the wildest conjectures to account for this lack of correspondence between the shell and its contents, to explain, in short, a fact which is inexplicable once the propitious moment has passed. On the natural site, in the cells of the 125 The Glow-Worm andi Other Beetles Anthophora, this apparent anomaly never occurs, because the secondary larva, when on the point of transformation into the pseudochrysalis, is always careful to place its head uppermost, according as the axis of the cell more or less nearly approaches the vertical. But, when the pseudochrysalids are placed higgledy-piggledy in a box or jar, all those which are upside down will later contain inverted larvae or nymphs. After four changes of form so profound as those which I have described, one might reasonably expect to find some modifications of the internal organization. Nevertheless, nothing is changed; the nervous system is the same in the tertiary larva as in the earlier phases; the reproductive organs do not yet show; and there is no need to mention the digestive apparatus, which remains invari- able even in the perfect insect. The duration of the tertiary larva is a bare four or five weeks, which is also about the duration of the second. In July, when the secondary larva passes into the pseudo- chrysalid stage, the tertiary larva passes into the nymphal stage, still inside the double vesicular envelope. Its skin splits along the back in front; and with the assistance of a few feeble contractions, which reappear at 126 Hypermetamorphosis this juncture, it is thrust behind in the shape of a little ball. There is therefore nothing here that differs from what happens in the other Beetles. Nor does the nymph which succeeds this tertiary larva present any peculiarity: it is the perfect insect in swaddling-bands, yellow- ish white, with its various external members, clear as crystal, displayed under the ab- domen. A few weeks elapse, during which the nymph partly dons the livery of the adult state ; and, in about a month, the insect moults for a last time, in the usual manner, in order to attain its final form. The wing- cases are now of a uniform yellowish white, as are the wings, the abdomen and the greater part of the legs; very nearly all the rest of the body is of a glossy black. In the space of twenty-four hours, the wing-cases assume their half-black, half-russet colouring; the wings grow darker; and the legs finish turn- ing black. This done, the adult organism is completed. However, the Sitaris remains still a fortnight in the intact shell, ejecting at intervals white droppings of uric acid, which it pushes back together with the shreds of its last two sloughs, those of the tertiary larva and of the nymph. Lastly, about the middle of August, it tears the double bag 127 The Glow- Worm and Other Beetles that contains it, pierces the lid of the Antho- phora's cell, enters a corridor and appears outside in quest of the other sex. I have told how, while digging in search of the Sitaris, I found two cells belonging to Meloe cicatricosus. One contained an An- thophora's egg; with this egg was a yellow Louse, the primary larva of the Meloe. The history of this tiny creature we know. The second cell also was full of honey. On the sticky liquid floated a little white larva, about a sixth of an inch in length and very differ- ent from the other little white larvae be- longing to Sitares. The rapid fluctuations of the abdomen showed that it was eagerly drinking the strong-scented nectar collected by the Bee. This larva was the young Meloe in the second period of its development. I was not able to preserve these two precious cells, which I had opened wide to examine the contents. On my return from Carpentras, I found that their honey had been spilt by the motion of the carriage and that their inhabitants were dead. On the 25th of June, a fresh visit to the nests of the Anthophorae furnished me with two larvae like the foregoing, but much larger. One of them was on the point of finishing its store of honey, the other still had nearly half left. 128 Hypermetamorphosis The first was put in a place of safety with a thousand precautions, the second was at once immersed in alcohol. These larvae are blind, soft, fleshy, yel- lowish white, covered with a fine down visible only under the lens, curved into a fish-hook like the larvae of the Lamellicorns, to which they bear a certain resemblance in their ge- neral configuration. The segments, includ- ing the head, number thirteen, of which nine are provided with breathing-holes with a pale, oval rim. These are the mesothorax and the first eight abdominal segments. As in the Sitaris-larvae, the last pair of stigmata, that of the eighth segment of the abdomen, is less developed than the rest. The head is horny, of a light brown colour. The epistoma is edged with brown. The labrum is prominent, white and trape- zoidal. The mandibles are black, strong, short, obtuse, only slightly curved, sharp- edged and furnished each with a broad tooth on the inner side. The maxillary and labial palpi are brown and shaped like very small studs with two or three joints to them. The antennae, inserted just at the base of the mandibles, are brown, and consist of three sections: the first is thick and globular; the two others are much smaller in diameter and 129 The Glow- Worm and! Other Beetles cylindrical. The legs are short, but fairly strong, able to serve the creature for craw- ling or digging; they end in a strong black claw. The length of the larva when fully developed is one inch. As far as I can judge from the dissection of the specimen preserved in alcohol, whose viscera were affected by being kept too long in that liquid, the nervous system consists of eleven- ganglia, not counting the oesophageal collar; and the digestive apparatus does not differ perceptibly from that of an adult Oil- beetle. The larger of the two larvae of the 25th of June, placed in a test-tube with what re- mained of its provisions, assumed a new form- during the first week of the following month. Its skin split along the front dorsal half and, after being pushed half back, left partly un- covered a pseudochrysalis bearing the closest analogy with that -of the Sitares. Newport did not see the larva of the Oil-beetle in its second form, that which it displays when it is eating the mess of honey hoarded by the Bees, but he did see its moulted skin half- covering the pseudochrysalis which I have just mentioned. From the sturdy mandibles and the legs armed with a powerful claw which he observed on this moulted skin, New- 130 Hypermetamorphosis port assumed that, instead of remaining in the same Anthophora-cell, the larva, which is capable of burrowing, passes from one cell to another in search of additional nourish- ment. This suspicion seems to me to be well-founded, for the size which the larva finally attains exceeds the proportions which the small quantity of honey enclosed in a sin- gle cell would lead us to expect. Let us go back to the pseudochrysalis. It is, as in the Sitares, an inert body, of a horny consistency, amber-coloured and divided into thirteen segments, including the head. Its length is 20 millimetres.1 It is slightly curved into an arc, highly convex on the dorsal surface, almost flat on the ventral surface and edged with a projecting fillet which marks the division between the two. The head is only a sort of mask on which certain features are vaguely carved in still relief, corresponding with the future parts of the head. On the thoracic segments are three pairs of tubercles, corresponding with the legs of the recent larva and the future insect. Lastly, there are nine pairs of stig- mata, one pair on the mesothorax and the eight following pairs on the first eight seg- ments of the abdomen. The last pair is 1 .787 inch. — Translator's Note. The Glow-Worm and Other Beetles rather smaller than the rest, a peculiarity which we have already noted in the larva which precedes the pseudochrysalis. On comparing the pseudochrysalids of the Oil-beetles and Sitares, we observe a most striking similarity between the two. The same structure occurs in both, down to the smallest details. We find on either side the same cephalic masks, the same tubercles occupying the place of the legs, the same dis- tribution and the same number of stigmata and, lastly, the same colour, the same rigidity of the integuments. The only points of dif- ference are in the general appearance, which is not the same in the two pseudochrysalids, and in the covering formed by the cast skin of the late larva. In the Sitares, in fact, this cast skin constitutes a closed bag, a pouch completely enveloping the pseudochrysalis; in the Oil-beetles, on the contrary, it is split down the back and pushed to the rear and, consequently, only half-covers the pseudo- chrysalis. The post-mortem examination of the only pseudochrysalis in my possession showed me that, similarly to that which happens in the Sitares, no change occurred in the organi- zation of the viscera, notwithstanding the profound transformations which take place 132 Hypermetamorphosis externally. In the midst of innumerable lit- tle sacs of adipose tissue is buried a thin thread in which we easily recognize the es- sential features of the digestive apparatus, both of the preceding larval form and of the perfect insect. As for the medullary cord of the abdomen, it consists, as in the larva, of eight ganglia. In the perfect insect it comprises only four. I could not say positively how long the Oil-beetle remains in the pseudochrysalid form; but, if we consider the very complete analogy between the evolution of the Oil- beetles and that of the Sitares, there is rea- son to believe that a few pseudochrysalids complete their transformation in the same year, while others, in greater numbers, re- main stationary for a whole year and do not attain the state of the perfect insect until the following spring. This is also the opinion expressed by Newport. Be this as it may, I found at the end of August one of these pseudochrysalids which had already attained the nymphal stage. It is with the help of this precious capture that I shall be able to finish the story of the Oil- beetle's development. The horny integu- ments of the pseudochrysalis are split along a fissure which includes the whole ventral The Glow-Worm and Other Beetles surface and the whole of the head and runs up the back of the thorax. This cast skin, which is stiff and keeps its shape, is half- enclosed, as was the pseudochrysalis, in the skin shed by the secondary larva. Lastly, through the fissure, which divides it almost in two, a Meloe-nymph half-emerges; so that, to all appearances, the pseudochrysalis has been followed immediately by the nymph, which does not happen with the Sitares, which pass from the first of these two states to the second only by assuming an intermediary form closely resembling that of the larva which eats the store of honey. But these appearances are deceptive, for, on removing the nymph from the split sheath formed by the integuments of the pseudo- chrysalis, we find, at the bottom of this sheath, a third cast skin, the last of those which the creature has so far rejected. This skin is even now adhering to the nymph by a few tracheal filaments. If we soften it in water, we easily recognize that it possesses an organization almost identical with that which preceded the pseudochrysalis. In the latter case only, the mandibles and the legs are not so robust. Thus, after passing through the pseudochrysalid stage, the Oil- 134 Hypermetamorphosis beetles for some time resume the preceding form, almost without modification. The nymph comes next. It presents no peculiarities. The only nymph that I have reared attained the perfect insect state at the end of September. Under ordinary condi- tions would the adult Oil-beetle have emerged from her cell at this period? I do not think so, since the pairing and egg-laying do not take place until the beginning of spring. She would no doubt have spent the autumn and the winter in the Anthophora's dwelling, only leaving it in the spring following. It is even probable that, as a rule, the develop- ment is even slower and that the Oil-beetles, like the Sitares, for the most part spend the cold season in the pseudochrysalid state, a state well-adapted to the winter torpor, and do not achieve their numerous forms until the return of the warm weather. The Sitares and Meloes belong to the same family, that of the Meloidas.1 Their strange transformations must probably ex- tend throughout the group ; indeed, I had the good fortune to discover a third example, which I have not hitherto been able to study 1 Later classifiers place both in the family of the Can- tharidas. — Translator's Note. 135 The Glow- Worm and Other Beetles in all its details after twenty-five years of investigation. On six occasions, no oftener, during this long period I have set eyes on the pseudochrysalis which I am about to de- scribe. Thrice I obtained it from old Chalicodoma-nests built upon a stone, nests which I at first attributed to the Chalicodoma of the Walls and which I now refer with greater probability to the Chalicodoma of the Sheds. I once extracted it from the gal- leries bored by some wood-eating larva in the trunk of a dead wild pear-tree, galleries afterwards utilized for the cells of an Osmia, I do not know which. Lastly, I found a pair of them in between the row of cocoons of the Three-pronged Osmia (O. trident ata, DUF.), who provides a home for her larvae in a channel dug in the dry bramble stems. The insect in question therefore is a parasite of the Osmiae. When I extract it from the old Chalicodoma-nests, I have to attribute it not to this Bee but to one of the Osmiae (O. tricornis and O. latreillii) who, when making their nests, utilize the old galleries of the Mason-bee. The most nearly complete instances that I have seen furnishes me with the following data: the pseudochrysalis is very closely en- veloped in the skin of the secondary larva, a 136 Hypermetamorphosis skin consisting of fine transparent pellicle, without any rent whatever. This is the pouch of the Sitaris, save that it lies in imme- diate contact with the body enclosed. On this jacket we distinguish three pairs of tiny legs, reduced to short vestiges, to stumps. The head is in place, showing quite percep- tibly the fine mandibles and the other parts of the mouth. There is no trace of eyes. Each side has a white edging of shrivelled tracheae, running from one stigmatic orifice to an- other. Next comes the pseudochrysalis, horny, currant-red, cylindrical, cone-shaped at both ends, slightly convex on the dorsal surface and concave on the ventral surface. It is covered with delicate, prominent spots, sprinkled very close together; it takes a lens to show them. It is i centimetre long and 4 millimetres wide.1 We can distinguish a large knob of a head, on which the mouth is vaguely outlined; three pairs of little shiny brown specks, which are the hardly per- ceptible vestiges of the legs; and on each side a row of eight black specks, which are the stigmatic orifices. The first speck stands by itself, in front ; the seven others, divided from the first by an empty space, form a continu- 1 .393 x .156 inch. — Translator's Note. 137 The Glow-Worm and Other Beetles ous row. Lastly, at the opposite end is a little pit, the sign of the anal pore. Of the six pseudochrysalids which a lucky accident placed at my disposal, four were dead; the other two were furnished by Zo- nitis mutica. This justified my forecast, which from the first, with analogy for my guide, made me attribute these curious or- ganizations to the genus Zonitis. The meloidal parasite of the Osmiae, therefore, is recognized. We have still to make the acquaintance of the primary larva, which gets itself carried by the Osmia into the cell full of honey, and the tertiary larva, the one which, at a given moment, must be found con- tained in the pseudochrysalis, a larva which will be succeeded by the nymph. Let us recapitulate the strange metamor- phoses which I have sketched. Every Beetle-larva, before attaining the nymphal stage, undergoes a greater or smaller num- ber of moults, of changes of skin ; but these moults, which are intended to favour the de- velopment of the larva by ridding it of co- vering that has become too tight for it, in no way alter its external shape. After any moult that it may have undergone, the larva retains the same characteristics. If it begin by being tough, it will not become tender; if 138 Hypermetamorphosis it be equipped with legs, it will not be de- prived of them later; if it be provided with ocelli, it will not become blind. It is true that the diet of these non-variable larvae re- mains the same throughout their duration, as do the conditions under which they are destined to live. But suppose that this diet varies, that the environment in which they are called upon to live changes, that the circumstances ac- companying their development are liable to great changes: it then becomes evident that the moult may and even must adapt the or- ganization of the larva to these new con- ditions of existence. The primary larva of the Sitaris lives on the body of the Anthro- phora. Its perilous peregrinations demand agility of movement, long-sighted eyes and masterly balancing-appliances; it has, in fact, a slender shape, ocelli, legs and special organs adapted to averting a fall. Once inside the Bee's cell, it has to destroy the egg; its sharp mandibles, curved into hooks, will fulfil this office. This done, there is a change of diet: after the Anthophora's egg the larva pro- ceeds to consume the ration of honey. The environment in which it has to live also changes: instead of balancing itself on a hair of the Anthophora, it has now to float 139 The Glow- Worm and Other Beetles on a sticky fluid; instead of living in broad daylight, it has to remain plunged in the pro- foundest darkness. Its sharp mandibles must therefore become hollowed into a spoon that they may scoop up the honey; its legs, its cirri, its balancing-appliances must dis- appear as useless and even harmful, since all these organs can only involve the larva in serious danger, by causing it to stick in the honey; its slender shape, its horny in- teguments, its ocelli, being no longer neces- sary in a dark cell where movement is im- possible, where there are no rough en- counters to be feared, may likewise give place to complete blindness, to soft integuments, to a heavy, slothful form. This transfigura- tion, which everything shows to be indis- pensable to the life of the larva, is effected by a simple moult. We do not so plainly perceive the necessity of the subsequent forms, which are so ab- normal that nothing like them is known in all the rest of the insect class. The larva which is fed on honey first adopts a false chrysalid appearance and afterwards goes back to its earlier form, though the necessity for these transformations escapes us entirely. Here I am obliged to record the facts and to leave the task of interpreting them to the 140 Hypermetamorphosis future. The larva of the Meloidse, there- fore, undergo four moults before attaining the nymphal state; and after each moult their characteristics alter most profoundly. During all these external changes, the in- ternal organization remains unchangingly the same; and it is only at the moment of the nymph's appearance that the nervous system becomes concentrated and that the reproduct- ive organs are developed, absolutely as in the other Beetles. Thus, to the ordinary metamorphoses which make a Beetle pass successively through the stages of larva, nymph and per- fect insect, the Meloidae add others which repeatedly transform the larva's exterior, without introducing any modification of its viscera. This mode of development, which preludes the customary entomological forms by the multiple transfigurations of the larva, certainly deserves a special name: I sug- gest that of hypermetamorphosis. Let us now recapitulate the more promi- nent facts of this essay. The Sitares, the Meloes, the Zonites and apparently other Meloidse, possibly all of them, are in their earliest infancy parasites of the harvesting Bees. The larva of the Meloidae, before reach- Mi The Glow-Worm and Other Beetles ing the nymphal state, passes through four forms, which I call the primary larva, the secondary larva, the pseudochrysalis and the tertiary larva. The passage from one of these forms to the next is effected by a simple moult, without any changes in the viscera. The primary larva is leathery and settles on the Bee's body. Its object is to get itself carried into a cell filled with honey. On reaching the cell, it devours the Bee's egg; and its part is played. The secondary larva is soft and differs completely from the primary larva in its ex- ternal characteristics. It feeds upon the honey contained in the usurped cell. The pseudochrysalis is a body deprived of all movement and clad in horny in- teguments which may be compared with those of the pupae and chrysalids. On these in- teguments we see a cephalic mask without distinct or movable parts, six tubercles in- dicating the legs and nine pairs of breathing- holes. In the Sitares the pseudochrysalis is enclosed in a sort of sealed pouch and in the Zonites in a tight-fitting bag formed of the skin of the secondary larva. In the Meloes it is simply half-sheathed in the split skin of the secondary larva. The tertiary larva reproduces almost ex- 142 Hypermetamorphosis actly the peculiarities of the second; it is en- closed, in the Sitares and probably also the Zonites, in a double vesicular envelope formed of the skin of the secondary larva and the slough of the pseudochrysalis. In the Meloes, it is half-enclosed in the split in- teguments of the pseudochrysalis, even as these, in their turn, are half-enclosed in the skin of the secondary larva. From the tertiary larva onwards the metamorphoses follow their habitual course, that is to say, this larva becomes a nymph; and this nymph the perfect insect. 143 CHAPTER VI CEROCOM^:, MYLABRES AND ZONITES ALL has not been told concerning the Meloidae, those strange parasites, some of which, the Sitares and the Oil-beetles, attach themselves, like the tiniest of Lice, to the fleece of various Bees to get them- selves carried into the cell where they will destroy the egg and afterwards feed upon the ration of honey. A most unex- pected discovery, made a few hundred yards from my door, has warned me once again how dangerous it is to generalize. To take it for granted, as the mass of data hitherto collected seemed to justify us in doing, that all the Meloidae of our country usurp the stores of honey accumulated by the Bees, was surely a most judicious and natural ge- neralization. Many have accepted it with- out hesitation; and I for my part was one of them. For on what are we to base our conviction when we imagine that we are stating a law? We think to take our stand upon the general; and we plunge into the 144 Cerocomae, Mylabres and Zonites quicksands of error. And behold, the law of the Meloidae has to be struck off the statutes, a fate common to many others, as this chapter will prove. On the 1 6th of July, 1883, I was digging, with my son fimile, in the sandy heap where, a few days earlier, I had been observing the labours and the surgery of the Mantis-killing Tachytes. My purpose was to collect a few cocoons of this Digger-wasp. The cocoons were turning up in abundance under my pocket-trowel, when Emile presented me with an unknown object. Absorbed in my task of collection, I slipped the find into my box without examining it further than with a rapid glance. We left the spot. Half-way home, the ardour of my search became as- suaged; and a thought of the problematical object, so negligently dropped into the box among the cocoons, flashed across my mind. "Hullo!" I said to myself. "Suppose it were that? Why not? But, no, yes, it is that; that's just what it isl" Then, suddenly turning to Emile, who was rather surprised by this soliloquy: " My boy," I said, " you have had a mag- nificent find. It's a pseudochrysalis of the Meloidae. It's a document of incalculable value; you've struck a fresh vein in the ex- 145 The Glow- Worm and Other Beetles traordinary records of these creatures. Let us look at it closely and at once." The thing was taken from the box, dusted by blowing on it and carefully examined. I really had before my eyes the pseudo- chrysalis of some Meloid. Its shape was unfamiliar to me. No matter: I was an old hand and could not mistake its source. Everything assured me that I was on the track of an insect that rivalled the Sitares and the Oil-beetles in the strangeness of its transformations ; and, what was a still more precious fact, its occurrence amid the burrows of the Mantis-killer told me that its habits would be wholly different. "It's very hot, my poor Emile; we are both of us pretty done. Never mind: let's go back to our sand-hill and dig and have another search. I must have the larva that conies before the pseudochrysalis; I must, if possible, have the insect that comes out of it." Success responded amply to our zeal. We found a goodly number of pseudochrysalids. More often still, we unearthed larvae which were busy eating the Mantes, the rations of the Tachytes. Are these really the larvae that turn into the pseudochrysalids? It seems very probable, but there is room for 146 Cerocomae, Mylabres and Zonites doubt. Rearing them at home will dispel the mists of probability and replace them by the light of certainty. But that is all: I have not a vestige of the perfect insect to inform me of the nature of the parasite. The fu- ture, let us hope, will fill this gap. Such was the result of the first trench opened in the heap of sand. Later searches enriched my harvest a little, without furnishing me with fresh data. Let us now proceed to examine my double find. And first of all the pseudochrysalis, which put me on the alert. It is a motion- less, rigid body, of a waxen yellow, smooth, shiny, curved like a fish-hook towards the head, which is inflected. Under a very powerful magnifying-glass the surface is seen to be strewn with very tiny points which are slightly raised and shinier than the surface. There are thirteen segments, including the head. The dorsal surface is convex, the ventral surface flat. A blunt ridge divides the two surfaces. The three thoracic seg- ments bear each a pair of tiny conical nipples, of a deep rusty red, signs of the future legs. The stigmata are very distinct, appearing as specks of a deeper red than the rest of the integuments. There is one pair, the largest, on the second segment of the thorax, almost 147 The Glow-Worm and Other Beetles on the line dividing it from the first segment. Then follow eight pairs, one on each seg- ment of the abdomen except the last, making in all nine pairs of stigmata. The last pair, that of the eighth abdominal segment, is the smallest. The anal extremity displays no peculiarity. The cephalic mask comprises eight cone- shaped tubercles, dark red like the tubercles of the legs. Six of these are arranged in two lateral rows; the others are between the two rows. In each row of three nipples, the one in the middle is the largest; it no doubt cor- responds with the mandibles. The length of this organism varies greatly, fluctuating be- tween 8 and 15 millimetres.1 Its width is from 3 to 4 millimetres.2 Apart from the general configuration, it will be seen that we have here the strikingly characteristic appearance of the pseudo- chrysalids of the Sitares, Oil-beetles and Zonites. There are the same rigid in- teguments, of the red of a cough-lozenge or virgin wax; the same cephalic mask, in which the future mouth-parts are represented by faintly marked tubercles; the same thoracic studs, which are the vestiges of the legs ; the 1.3i2 to .585 inch. — Translator's Note. 2 .117 to .156 inch. — Translator's Note. 148 Cerocomae, Mylabres and Zonites same distribution of the stigmata. I was therefore firmly convinced that the parasite of the Mantis-hunters could only be a Meloid. Let us also record the description of the strange larva found devouring the heap of Mantes in the burrows of the Tachytes. It is naked, blind, white, soft and sharply curved. Its general appearance suggests the larva of some Weevil. I should be even more accurate if I compared it with the secondary larva of Meloe cicatricosus, of which I once published a drawing in the Annales des sciences naturelles.1 If we re- duce the dimensions considerably, we shall have something very like the parasite of the Tachytes. The head is large, faintly tinged with red. The mandibles are strong, bent into a pointed hook, black at the tip and a fiery red at the base. The antennae are very short, inserted close to the root of the mandibles. I count three joints: the first thick and globular, the other two cylindrical, the second of these cut short abruptly. There are twelve segments, apart from the head, divided by fairly 1 It was his essays in this periodical, on the metamor- phoses of the Sitares and Oil-beetles, that procured Fabre his first reputation as an entomologist. — Translator's Note. 149 The Glow-Worm and Other Beetles definite grooves. The first thoracic segment is a little longer than the rest, with the dor- sal plate very slightly tinged with russet, as is the top of the head. Beginning with the tenth segment, the body tapers a little. A slight scalloped rim divides the dorsal from the ventral surface. The legs are short, white and transparent and end in a feeble claw. A pair of stig- mata on the mesothorax, near the line of junction with the prothorax; a stigma on either side of the first eight abdominal seg- ments; in all nine pairs of stigmata, dis- tributed like those of the pseudochrysalis. These stigmata are small, tinged with red and rather difficult to distinguish. Varying in size, like the pseudochrysalid which seems to come from it, this larva averages nearly half an inch in length and an eighth of an inch in width. The six little legs, feeble though they be, perform services which one would not at first suspect. They embrace the Mantis that is being devoured and hold her under the mandibles, while the grub, lying on its side, takes its meal at its ease. They also serve for locomotion. On a firm surface, such as the wooden top of my table, the larva can move about quite well; it toddles along, 150 Cerocomae, Mylabres and Zonites dragging its belly, with its body straight from end to end. On fine, loose sand, change of position becomes difficult. The grub now bends itself into a bow; it wriggles upon its back, upon its side ; it crawls a little way ; it digs and heaves with its mandibles. But let a less crumbling support come to its assist- ance; and pilgrimages of some length are not beyond its powers. I reared my guests in a box divided into compartments by means of paper partitions. Each space, representing about the capacity of a Tachytes-cell, received its layer of sand, its pile of Mantes and its larva. And more than one disturbance arose in this refectory, where I had reckoned upon keeping the banqueters isolated one from the other, each at its special table. This larva, which had finished its ration the day before, was dis- covered next day in another chamber, where it was sharing its neighbour's repast. It had therefore climbed the partition, which for that matter was of no great height, or else had forced its way through some chink. This is enough, I think, to prove that the grub is not a strict stay-at-home, as are the larvae of the Sitares and the Oil-beetles when de- vouring the ration of the Anthophora. I imagine that, in the burrows of the The Glow- Worm and Other Beetles Tachytes, the grub, when its heap of Mantes is consumed, moves from cell to cell until it has satisfied its appetite. Its subterranean excursions cannot cover a wide range, but they enable it to visit a few adjacent cells. I have mentioned how greatly the Tachytes' provision of Mantes varies.1 The smaller rations certainly fall to the males, which are puny dwarfs compared with their compani- ons; the more plentiful fall to the females. The parasitic grub to which fate has al- lotted the scanty masculine ration has not perhaps sufficient with this share ; it wants an extra portion, which it can obtain by chan- ging its cell. If it be favoured by chance, it will eat according to the measure of its hunger and will attain the full develop- ment of which its race allows; if it wander about without finding anything, it will fast and will remain small. This would explain the differences which I note in both the grubs and the pseudochrysalids, differences amounting in linear dimensions to a hundred per cent and more. The rations, rare or abundant according to the cells lit upon, would determine the size of the parasite. During the active period, the larva un- 1 The essay on the Tachytes has not yet appeared in English. It will form part of a volume entitled More Hunting Wasps. — Translator's Note. 152 Cerocomae, Mylabres and Zonites dergoes a few moults; I have witnessed at least one of these. The creature stripped of its skin appears as it was before, without any change of form. It instantly resumes its meal, which was interrupted while the old skin was shed; it embraces with its legs an- other Mantis on the heap and proceeds to nibble her. Whether simple or multiple, this moult has nothing in common with the renewals due to the hypermetamorphosis, which so profoundly change the creature's appearance. Ten days' rearing in the partitioned box is enough to prove how right I was when I looked upon the parasitic larva feeding on Mantes as the origin of the pseudochrysalis, the object of my eager attention. The creature, which I kept supplied with addi- tional food as long as it accepted it, stops eating at last. It becomes motionless, re- tracts its head slightly and bends itself into a hook. Then the skin splits across the head and down the thorax. The tattered slough is thrust back; and the pseudochrysalis ap- pears in sight, absolutely naked. It is white at first, as the larva was ; but by degrees and fairly rapidly it turns to the russet hue of virgin wax, with a brighter red at the tips of the various tubercles which indicate the 153 The Glow- Worm and Other 'Beetles future legs and mouth-parts. This shed- ding of the skin, which leaves the body of the pseudochrysalis uncovered, recalls the mode of transformation observed in the Oil- beetles and is different from that of the Sitares and the Zonites, whose pseudo- chrysalis remains wholly enveloped in the skin of the secondary larva, a sort of bag which is sometimes loose, sometimes tight and always unbroken. The mist that surrounded us at the out- set is dispelled. This is indeed a Meloid, a true Meloid, one of the strangest anomalies among the parasites of its tribe. Instead of living on the honey of a Bee, it feeds on the skewerful of Mantes provided by a Tachytes. The North-American naturalists have taught us lately that honey is not always the diet of the Blister-beetles : some Meloidae in the United States devour the packets of eggs laid by the Grasshoppers. This is a legitimate acquisition on their part, not an illegal seizure of the food-stores of others. No one, as far as I am aware, had as yet suspected the true parasitism of a carnivor- ous Meloid. It is nevertheless very remark- able to find in the Blister-beetles, on both sides of the Atlantic, this weakness for the flavour of Locust : one devours her eggs ; the iS4 Cerocomae, Mylabres and Zonites other a representative of the order, in the shape of the Praying Mantis and her kin. Who will explain to me this predilection for the Orthopteron in a tribe whose chief, the Oil-beetle, accepts nothing but the mess of honey? Why do insects which appear close together in all our classifications possess such opposite tastes? If they spring from a common stock, how did the consumption of flesh supplant the consumption of honey? How did the Lamb become a Wolf? This is the great problem which was once set us, in an inverse form, by the Spotted Sapyga, a honey-eating relative of the flesh-eating Scolia.1 I submit the question to whom it may concern. The following year, at the beginning of June, some of my pseudochrysalids split open transversely behind the head and lengthwise down the whole of the median line of the back, except the last two or three segments. From it emerges the tertiary larva, which, from a simple examination with the pocket- lens, appears to me, in its general features, identical with the secondary larva, the one which eats the Tachytes' provisions. It is naked and pale-yellow, the 'colour of butter. 1 The essays on these will appear in the volume, en- titled The Hunting Wasps, aforementioned. — Translator's Note. 155 The Glow- Worm and Other Beetles It is active and wriggles with awkward move- ments. Ordinarily it lies upon its side, but it can also stand in the normal position. The creature is then trying to use its legs, without finding sufficient purchase to enable it to walk. A few days later, it relapses into complete repose. Thirteen segments, including the head, which is large, with a quadrilateral cranium, rounded at the sides. Short antennae, con- sisting of three knotted joints. Powerful curved mandibles, with two or three little teeth at the end, of a fairly bright red. Labial palpi rather bulky, short and with three joints, like the antennae. The mouth- parts, labrum, mandibles and palpi are mova- ble and stir slightly, as though seeking food. A small brown speck near the base of each antenna, marking the place of the future eyes. Prothorax wider than the segments that come after it. These are all of one width and are distinctly divided by a furrow and a slight lateral rim. Legs short, trans- parent, without a terminal claw. They are three-jointed stumps. Pale stigmata, eight pairs of them, placed as in the pseudochry- salis, that is, the first and largest pair on the line dividing the first two segments of the thorax and the seven others on the first seven 156 Cerocomae, Mylabres and Zonites abdominal segments. The secondary larva and the pseudochrysalis also have a very small stigma on the penultimate segment of the abdomen. This stigma has disappeared in the tertiary larva ; at least I cannot detect it with the aid of a good magnify ing-glass. Lastly, we find the same strong mandibles as in the secondary larva, the same feeble legs, the same appearance of a Weevil-grub. The movements return, but are less clearly marked than in the primary form. The passage through the pseudochrysalid state has led to no change that is really worth de- scribing. The creature, after this singular phase, is what it was before. The Meloes and Sitares, for that matter, behave similarly. Then what can be the meaning of this pseudochrysalid stage, which, when passed, leads precisely to the point of departure? The Meloid seems to be revolving in a circle : it undoes what it has just done, it draws back after advancing. The idea sometimes occurs to me to look upon the pseudo- chrysalis as a sort of egg of a superior or- ganization, starting from which the insect follows the ordinary law of entomological phases and passes through the successive stages of larva, nymph and perfect insect. The first hatching, that of the normal egg, iS7 The Glow- Worm and Other Beetles makes the Meloid go through the larval dimorphism of the Anthrax and the Leuco- spis. The primary larva finds its way to the victuals ; the secondary larva consumes them. The second hatching, that of the pseudo- chrysalis, reverts to the usual course, so that the insect passes through the three customary forms : larva, nymph, adult. The tertiary larval stage is of brief dura- tion, lasting about a fortnight. The larva then sheds its skin by a longitudinal rent along the back, as did the secondary larva, uncovering the nymph, in which we recognize the Beetle, the genus and species being almost determinable by the antennae. The second year's development turned out badly. The few nymphs which I obtained about the middle of June shrivelled up with- out attaining the perfect form. Some pseudochrysalids remained on my hands without showing any sign of approaching transformation. I attributed this delay to lack of warmth. I was in fact keeping them in the shade, on a what-not, in my study, whereas under natural conditions they are ex- posed to the hottest sun, beneath a layer of sand a few inches deep. To imitate these conditions without burying my charges, whose progress I wished to follow comfortably, I 158 Cerocomae, Mylabres and Zonites placed the pseudochrysalids that remained on a layer of fresh sand at the bottom of a glass receiver. Direct exposure to the sun was im- practicable : it would have been fatal at a period when life is subterranean. To avoid it, I tied over the mouth of the receiver a few thicknesses of black cloth, to represent the natural screen of sand; and the apparatus thus prepared was exposed for some weeks to the most brilliant sunshine in my window. Under the cloth cover, which, owing to its colour, favours the absorption of heat, the temperature, during the day-time, became that of an oven; and yet the pseudochrysalids persisted in remaining stationary. The end of July was near and nothing indicated a speedy hatching. Convinced that my at- tempts at heating would be fruitless, I re- placed the pseudochrysalids in the shade, on the shelves, in glass tubes. Here they passed a second year, still in the same con- dition. June returned once more and with it the appearance of the tertiary larva, followed by the nymph. For the second time this stage of development was not exceeded; the one and only nymph that I succeeded in ob- taining shrivelled, like those of the year be- fore. Will these two failures, arising no 159 The Glow- Worm and Other Beetles doubt from the overdry atmosphere of my receivers, conceal from us the genus and the species of the Mantis-eating Meloid? For- tunately, no. The riddle is easily solved by deduction and comparison. The only Melodiae in my part of the country which, though their habits are still unknown, might correspond in size with either the larva or the pseudochrysalis in question are the Twelve-pointed Mylabris and Schaeffer's Cerocoma. I find the first in July on the flowers of the sea scabious; I find the second at the end of May and in June on the heads of the lies d'Hyeres ever- lasting. This last date is best-suited to ex- plain the presence of the parasitic larva and its pseudochrysalis in the Tachytes' burrows from July onwards. Moreover, the Cero- coma is very abundant in the neighbourhood of the sand-heaps haunted by the Tachytes, while the Mylabris does not occur there. Nor is this all : the few nymphs obtained have curious antennae, ending in a full, irregular tuft, the like of which is found only in the antennae of the male Cerocoma. The Myla- bris, therefore, must be eliminated; the an- tennas, in the nymph, must be regularly jointed, as they are in the perfect insect. There remains the Cerocoma. r6o Cerocomae, Mylabres and Zonites Any lingering doubts may be dispelled : by good fortune, a friend of mine, Dr. Beaure- gard, who is preparing a masterly work upon the Blister-beetles, had some pseudochry- salids of Schreber's Cerocoma in his possess- ion. Having visited Serignan for the pur- pose of scientific investigations, he had searched the Tachytes' sand-heaps in my company and taken back to Paris a few pseudochrysalids of grubs fed on Mantes, in order to follow their development. His at- tempts, like mine, had miscarried; but, on comparing the Serignan pseudochrysalids with those of Schreber's Cerocoma, which came from Aramon, near Avignon, he was able to establish the closest resemblance be- tween the two organisms. Everything there- fore confirms the supposition that my dis- covery can relate only to Schaeffer's Cero- coma. As for the other, it must be elimi- nated: its extreme rarity in my neighbour- hood is a sufficient reason. It is tiresome that the diet of the Aramon Meloid is not known. If I allowed my- self to be guided by analogy, I should be in- clined to regard Schreber's Cerocoma as a parasite of Tachytes tarsina, who buries her hoards of young Locusts in the high sandy banks. In that case, the two Cerocomae 161 The Glow- Worm and Other Beetles would have a similar diet. But I leave it to Dr. Beauregard to elucidate this important characteristic. The riddle is deciphered: the Meloid that eats Praying Mantes is Schaeffer's Cero- coma, of whom I find plenty, in the spring, on the blossoms of the everlasting. When- ever I see it, my attention is attracted by an unusual peculiarity: the great difference of size that is able to exist between one speci- men and another, albeit of the same sex. I see stunted creatures, females as well as males, which are barely one third the length of their better-developed companions. The Twelve-spotted Mylabris and the Four- spotted Mylabris present differences quite as pronounced in this respect. The cause which makes a dwarf or a giant of the same insect, irrespective of its sex, can be only the smaller or greater quantity of food. If the larva, as I suspect, is obliged to find the Tachytes' game-larder for itself and to visit a second and a third, when the first is too frugally furnished, it may be imagined that the hazard of the road does not favour all in the same way, but rather allots abundance to one and penury to an- other. The grub that does not eat its fill remains small, while the one that gluts itself 162 Cerocomae, Mylabres and Zonites grows fat. These differences of size, in them- selves, betray parasitism. If a mother's pains had amassed the food, or if the family had had the industry to obtain it direct in- stead of robbing others, the ration would be practically equal for all; and the inequalities in size would be reduced to those which often occur between the two sexes. They speak, moreover, of a precarious, risky parasitism, wherein the Meloid is not sure of finding its food, which the Sitaris finds so deftly, getting itself carried by the Anthophora, after being born at the very entrance to the Bee's galleries and leaving its retreat only to slip into its host's fleece. A vagabond obliged to find for itself the food that suits it, the Cerocoma incurs the risk of Lenten fare. One chapter is lacking to complete the his- tory of Schaeffer's Cerocoma: that which treats of the beginning, the laying of the eggs, the egg itself and the primary larva. While watching the development of the Mantis- eating parasite, I took my precautions, in the first year, to discover its starting-point. By eliminating what was known to me and seek- ing among the Meloidae of my neighbour- hood for the size that corresponded with the pseudochrysalids unearthed from the 163 The Glow- Worm and Other Beetles Tachytes' burrows, I found, as I have said, only Schaeffer's Cerocoma and the Twelve- spotted Mylabris. I undertook to rear these in order to obtain their eggs. As a standard of comparison, the Four- spotted Mylabris, of a more imposing size, was added to the first two. A fourth, Zonitis mutica, whom I did not need to con- sult, knowing that she was not connected with the matter in hand and being familiar with her pseudochrysalis, completed my school of egg-layers. I proposed, if possible, to obtain her primary larva. Lastly, I had formerly reared some Cantharides with the object of observing their egg-laying. In all, five species of Blister-beetles, reared in a breeding-cage, have left a few lines of notes in my records. The method of rearing is of the simplest. Each species is placed under a large wire- gauze dome standing in a basin filled with earth. In the middle of the enclosure is a bottle full of water, in which the food soaks and keeps fresh. For the Cantharides, this is a bundle of ash-twigs; for the Four-spotted Mylabris, a bunch of bindweed (Convolvus arvensis} or psoralea (P. bituminosa), of which the insect nibbles only the corollae. For the Twelve-spotted Mylabris, I provide 164 Cerocomae, Mylabres and Zonites blossoms of the scabious (Scabiosa man- tima) : for the Zonitis, the full-blown heads of the eryngo (Eryngium campestre) ; for Schaeffer's Cerocoma, the heads of the lies d'Hyeres everlasting (Helichrysum stcechas) . These three last nibble more particularly the anthers, more rarely the petals, never the leaves. A sorry intellect and sorry manners, which hardly repay the minute cares involved in the rearing. To browse, to love her lord, to dig a hole in the earth and carelessly to bury her eggs in it: that is the whole life of the adult Meloid. The dull creature acquires a little interest only at the moment when the male begins to toy with his mate. Every species has its own ritual in declaring its passion; and it is not beneath the dignity of the observer to witness the manifestations, sometimes so very strange, of the universal Eros, who rules the world and brings a tremor to even the lowest of the brute crea- tion. This is the ultimate aim of the insect, which becomes transfigured for this solemn function and then dies, having no more to do. A curious book might be written on the subject of love among the beasts. Long ago the subject tempted me. For a quarter of a century my notes have been slumbering, 165 The Glow-Worm and Other Beetles dustily, in a corner of my library. I extract from them the following details concerning the Cantharides. I am not the first, I know, to describe the amorous preludes of the Meloid of the Ash-tree; but the change of narrator may give the narrative a certain value : it confirms what has already been said and throws light upon some points which may have escaped notice. A female Cantharides is peacefully nib- bling her leaf. A lover comes upon the scene, approaches her from behind, suddenly mounts upon her back and embraces her with his two pairs of hind-legs. Then with his abdomen, which he lengthens as much as possible, he energetically slaps that of the female, on the right side and the left by turns. It is like the strokes of a washerwoman's bat, delivered with frenzied rapidity. With his antennae and his fore-legs, which remain free, he furiously lashes the neck of the vic- tim. While the blows fall thick as hail, in front and behind, the head and corselet of the amorous swain are shaken by an ex- travagant swaying and trembling. You would think that the creature was having an epileptic fit. Meanwhile, the beloved makes herself small, opening her wing-cases slightly, hiding 166 Cerocomae, Mylabres and Zonites her head and tucking her abdomen under her, as though to escape the erotic thunderstorm that is bursting upon her back. But the paroxysm calms down. The male extends his fore-legs, shaken by a nervous tremor, like the arms of a cross and in this ecstatic posture seems to call upon the heavens to witness the ardour of his desires. The antennae and the belly are held motionless, in a straight line; the head and the corselet alone continue to heave rapidly up and down. This period of repose does not last long. Short as it is, the female, her appetite undis- turbed by the passionate protestations of her wooer, imperturbably resumes the nibbling of her leaf. Another paroxysm bursts forth. Once more the male's blows rain upon the neck of the tightly-clasped victim, who hastens to bow her head upon her breast. But he has no intention of allowing his lady-love to escape. With his fore-legs, using a special notch placed at the juncture of the leg and the tarsus, he seizes both her antennas. The tarsus folds back; and the antennae are held as in a vice. The suitor pulls; and the callous one is forced to raise her head. In this posture the male reminds one of a horseman proudly sitting his steed and holding the The Glow- Worm and Other Beetles reins in both hands. Thus mastering his mount, he is sometimes motionless and some- times frenzied in his demonstrations. Then, with his long abdomen, he lashes the female's hinder-parts, first on one side, then on the other; the front part he flogs, hammers and pounds with blows of his antennae, head and feet. The object of his desires will be un- feeling indeed if she refuse to surrender to so passionate a declaration. Nevertheless she still requires entreating. The impassioned lover resumes his ecstatic immobility, with his quivering arms out- stretched like the limbs of a cross. At brief intervals the amorous outbursts, with blows conscientiously distributed, recur in alterna- tion with periods of repose, during which the male holds his fore-legs crosswise, or else masters the female by the bridle of her an- tennae. At last the flagellated beauty allows herself to be touched by the charm attendant on his thumps. She yields. Coupling takes place and lasts for twenty hours. The he- roic part of the male's performance is over. Dragged backwards behind the female, the poor fellow strives to uncouple himself. His mate carts him about from leaf to leaf, wher- ever she pleases, so that she may choose the bit of green stuff to her taste. Sometimes he 168 Cerocomae, Mylabres and Zonites also takes a gallant resolve and, like the fe- male, begins to browse. You lucky creatures, who, so as not to lose a moment of your four or five weeks' existence, yoke together the cravings of love and hunger! Your motto is, " A short life and a merry one." The Cerocoma, who is a golden green like the Cantharides, seems to have partly adopted the amorous rites of her rival in dress. The male, always the elegant sex in the insect tribe, wears special ornaments. The horns or antennae, magnificently com- plicated, form as it were two tufts of a thick head of hair. It is to this that the name Cerocoma refers: the creature crested with its horns. When a bright sun shines into the breeding-cage, it is not long before the in- sects form couples on the bunch of everlast- ings. Hoisted on the female, whom he em- braces and holds with his two pairs of hind- legs, the male sways his head and corselet up and down, all in a piece. This oscillatory movement has not the fiery precipitation of that of the Cantharides; it is calmer and as it were rhythmical. The abdomen more- over remains motionless and seems unskilled in those slaps, as of a washerwoman's bat, which the amorous denizen of the ash-tree so vigorously distributes with his belly. 169 The Glow-Worm and Other Beetles While the front half of the body swings up and down, the fore-legs execute magnetic passes on either side of the tight-clasped female, moving with a sort of twirl, so rapidly that the eye can hardly follow them. The female appears insensible to this flagel- latory twirl. She innocently curls her an- tennas. The rejected suitor leaves her and moves on to another. His dizzy, twirling passes, his protestations are everywhere re- fused. The moment has not yet arrived, or rather the spot is not propitious. Captivity appears to weigh upon the future mothers. Before listening to their wooers they must have the open air, the sudden joyful flight from cluster to cluster on the sunlit slope, all gold with everlastings. Apart from the idyll of the twirling passes, a mitigated form of the Cantharides' blows, the Cerocoma re- fused to yield before my eyes to the last act of the bridal. Among males the same oscillations of the body and the same lateral flagellations are frequently practised. While the upper one makes a tremendous to-do and whirls his legs, the one under him keeps quiet. Sometimes a third scatterbrain comes on the scene, some- times even a fourth, and mounts upon the heap of his predecessors. The uppermost 170 Cerocomae, Mylabres and Zonites bobs up and down and makes swift rowing- strokes with his fore-legs ; the others remain motionless. Thus are the sorrows of the rejected beguiled for a moment. The Zonites, a rude clan, grazing on the heads of the prickly eryngo, despise all tender preliminaries. A few rapid vibra- tions of the antennae on the males' part; and that is all. The declaration could not be briefer. The pairing, with the creatures placed end to end, lasts nearly an hour. The Mylabres also must be very expedi- tious in their preliminaries, so rmach so that my cages, which were kept well-stocked for two summers, provided me with numerous batches of eggs without giving me a single opportunity of catching the males in the least bit of a flirtation. Let us therefore consider the egg-laying. This takes place in August for our two species of Mylabres. In the vegetable mould which does duty as a floor to the wire-gauze dome, the mother digs a pit four-fifths of an inch deep and as wide as her body. This is the place for the eggs. The laying lasts barely half an hour. I have seen it last thirty-six hours with Sitares. This quickness of the Mylabris points to an incomparably less numerous family. The hiding-place is 171 The Glow- Worm and Other Beetles next closed. The mother sweeps up the rub- bish with her fore-legs, collects it with the rake of her mandibles and pushes it back into the pit, into which she now descends to stamp upon the powdery layer and cram it down with her hind-legs, which I see swiftly work- ing. When this layer is well packed, she starts raking together fresh material to com- plete the filling of the hole, which is carefully trampled stratum by stratum. I take the mother from her pit while she is engaged in filling it up. Delicately, with the tip of a camel-hair pencil, I move her a couple of inches. The Beetle does not return to her batch of eggs, does not even look for it. She climbs up the wire gauze and proceeds to graze among her companions on the bind- weed or scabious, without troubling herself further about her eggs, whose hiding-place is only half-filled. A second mother, whom I move only one inch, is no longer able to re- turn to her task, or rather does not think of doing so. I take a third, after shifting her just as slightly, and, while the forgetful creature is climbing up the trellis-work, bring her back to the pit. I replace her with her head at the opening. The mother stands motionless, looking thoroughly perplexed. She sways her head, passes her front tarsi 172 Cerocomae, Mylabres and Zonites through her mandibles, then moves away and climbs to the top of the dome without at- tempting anything. In each of these three cases I have to finish filling in the pit myself. What then are this maternity, which the touch of a brush causes to forget its duties, and this memory, which is lost at a distance of an inch from the spot? Compare with these shortcomings of the adult the expert machinations of the primary larva, which knows where its victuals are and as its first action introduces itself into the dwelling of the host that is to feed it. How can time and experience be factors of instinct? The new- born animalcule amazes us with its foresight; the adult insect astonishes us with its stu- pidity. With both Mylabres, the batch consists of some forty eggs, a very small number com- pared with those of the Oil-beetle and the Sitaris. This limited family was already foreseen, judging by the short space of time which the egg-layer spends in her under- ground lodging. The eggs of the Twelve- spotted Mylabris are white, cylindrical, rounded at both ends and measure a milli- metre and a half in length by half a milli- metre in width.1 Those of the Four-spotted J. 058 x. 019 inch. — Translator's Note. 173 The Glow- Worm and Other Beetles Mylabris are straw coloured and of an elon- gated oval, a trifle fuller at one end than at the other. Length, two millimetres; width, a little under one millimetre.1 Of all the batches of eggs collected, one alone hatched. The rest were probably sterile, a suspicion corroborated by the lack of pairing in the breeding-cage. Laid at the end of July, the eggs of the Twelve-spotted Mylabris began to hatch on the 5th of Sep- tember. The primary larva of this Meloid is still unknown, so far as I am aware; and I shall describe it in detail. It will be the starting-point of a chapter which perhaps will give us some fresh sidelights upon the history of the hypermetamorphosis. The larva is nearly 2 millimetres long.2 Coming out of a good-sized egg, it is en- dowed with greater vigour than the larvae of the Sitares and Oil-beetles. The head is large, rounded, slightly wider than the pro- thorax and of a rather brighter red. Man- dibles powerful, sharp, curved, with the ends crossing, of the same colour as the head, darker at the tips. Eyes black, prominent, globular, very distinct. Antennae fairly long, 1 .078 x .039 inch. — Translator's Note. 2 .078 inch. — Translators' Note. 174 Cerocomae, Mylabres and Zonites with three joints, the last thinner and pointed. Palpi very much pronounced. The first thoracic segment has very nearly the same diameter as the head and is much longer than those which come after. It forms a sort of cuirass equal in length to almost three abdominal segments. It is squared off in front in a straight line and is rounded at the sides and at the back. Its colour is bright red. The second ring is hardly a third as long as the first. It is also red, but a little browner. The third is dark brown, with a touch of green to it. This tint is repeated throughout the abdomen, so that in the matter of colouring the creature is divided into two sections : the front, which is a fairly bright red, includes the head and the first two thoracic segments; the second, which is a greenish brown, includes the third thoracic segment and the nine abdominal rings. The three pairs of legs are pale red, strong and long, considering the creature's small- ness. They end in a single long, sharp claw. The abdomen has nine segments, all of an olive brown. The membranous spaces which connect them are white, so that, from the second thoracic ring downwards, the tiny creature is alternatively ringed with white i7S The Glow-Worm and Other Beetles and olive brown. All the brown rings bris- tle with short, sparse hairs. The anal seg- ment, which is narrower than the rest, bears at the tip two long cirri, very fine, slightly waved and almost as long as the whole ab- domen. This description enables us to picture a sturdy little creature, capable of biting lustily with its mandibles, exploring the country with its big eyes and moving about with six strong harpoons as a support. We no longer have to do with the puny louse of the Oil-beetle, which lies in ambush on a cichoriaceous blos- som in order to slip into the fleece of a har- vesting Bee; nor with the black atom of the Sitaris, which swarms in a heap on the spot where it is hatched, at the Anthophora's door. I see the young Mylabris striding eagerly up and down the glass tube in which it was born. What is it seeking? What does it want? I give it a Bee, a Halictus,1 to see if it will settle on the insect, as the Sitares and Oil- beetles would not fail to do. My offer is scorned. It is not a winged conveyance that my prisoners require. The primary larva of the Mylabris there- 1 Cf. Bramble-bees and Others: chaps, xii. to xiv. — Translator's Note. Cerocomae, Mylabres and Zonites fore does not imitate those of the Sitaris and the Oil-beetle; it does not settle in the fleece of its host to get itself carried to the cell crammed with victuals. The task of seek- ing and finding the heap of food falls upon its own shoulders. The small number of the eggs that constitute a batch also leads to the same conclusion. Remember that the pri- mary larva of the Oil-beetle, for instance, set- tles on any insect that happens to pay a mo- mentary visit to the flower in which the tiny creature is on the look-out. Whether this visitor be hairy or smooth-skinned, a manu- facturer of honey, a canner of animal flesh or without any determined calling, whether she be Spider, Butterfly, Fly or Beetle makes no difference: the instant the little yellow louse espies the new arrival, it perches on her back and leaves with her. And now it all de- pends on luck! How many of these stray travellers must be lost; how many will never be carried into a warehouse full of honey, their sole food! Therefore, to remedy this enormous waste, the mother produces an in- numerable family. The Oil-beetle's batch of eggs is prodigious. Prodigious too is that of the Sitaris, who is exposed to similar mis- adventures. If, with her thirty or forty eggs, the Myla- The Glow- Worm and Other BeetleG bris had to run the same risks, perhaps not one larva would reach the desired goal. For so strictly limited a family a safer method is needed. The young larva must not get itself carried to the game-basket, or more probably to the honey-pot, at the risk of never reaching it; it must travel on its own legs. Allowing myself to be guided by the logic of things, I shall therefore complete the story of the Twelve-spotted Mylabris as follows. The mother lays her eggs underground near the spots frequented by the foster- mothers. The recently-hatched young grubs leave their lodgings in September and travel within a restricted radius in search of bur- rows containing food. The little creature's sturdy legs allow of these underground in- vestigations. The mandibles, which are just as strong, necessarily play their part. The parasite, on forcing its way into the food-pit, finds itself faced with either the egg or the young larva of the Bee. These are com- petitors, whom it is important to get rid of as quickly as possible. The hooks of the mandibles now come into play, tearing the egg or the defenceless grub. After this act of brigandage, which may be compared with that of the primary larva of the Sitaris rip- 178 Cerocomae, Mylabres and Zonites ping open and drinking the contents of the Anthophora's egg, the Meloid, now the sole possessor of the victuals, doffs its battle ar- ray and becomes the pot-bellied grub, the consumer of the property so brutally ac- quired. These are merely suspicions on my part, nothing more. Direct observation will, I believe, confirm them, so close is their con- nection with the known facts. Two Zonites, both visitors of the eryngo- heads during the heats of summer, are among the Meloidae of my part of the country. They are Zonitis mutica and Z. prausta. I have spoken of the first in another volume ; l I have mentioned its pseudochrysalis found in the cells of two Osmiae, namely, the Three-pronged Osmia, which piles its cells in a dry bramble-stem, and the Three-horned Osmia and also Latreille's Osmia, both of which exploit the nests of the Chalicodoma of the Sheds. The second Zonitis is to-day add- ing its quota of evidence to a story which is still very incomplete. I have obtained the Burnt Zonitis, in the first place, from the cot- ton pouches of Anthidium scapulare, who, like the Three-toothed Osmia, makes her nests in the brambles; in the second place, from the 1 Cf. Bramble-bees and Others: chaps, i., iii. and x.— Translator's Note. 179 The Glow-Worm and Other Beetles wallets of Megachile sericans, made with little round disks of the leaves of the com- mon acacia ; in the third place, from the cells which Anthidlum bellicosum 1 builds with par- titions of resin in the shell of a dead Snail. This last Anthidium is the victim also of the Unarmed Zonitis. Thus we have two closely-related exploiters for the same victim. During the last fortnight of July, I wit- ness the emergence of the Burnt Zonitis from the pseudochrysalis. The latter is cylin- drical, slightly curved and rounded at both ends. It is closely wrapped in the cast skin of the secondary larva, a skin consisting of a diaphanous bag, without any outlet, with running along each side a white tracheal thread which connects the various stigmatic apertures. I easily recognize the seven ab- dominal stigmata ; they are round and dimi- nish slightly in width from front to back. I also detect the thoracic stigma. Lastly, I perceive the legs, which are quite small, with weak claws, incapable of supporting the creature. Of the mouth-parts I see plainly only the mandibles, which are short, weak and brown. In short, the secondary larva 1 For the Cotton-bee, Leaf-cutter and Resin-bee men- tioned, cf. Bramble-bees and Others: passim. — Trans- lator's Note. 1 80 Cerocomae, Mylabres and Zonites was soft, white, big-bellied, blind, with rudi- mentary legs. Similar results were furnished by the shed skin of the secondary larva of Zonitis mutica, consisting, like the other, of a bag without an opening, fitting closely over the pseudochrysalis. Let us continue our examination of the relics of the Burnt Zonitis. The pseudo- chrysalis is red, the colour of a cough- lozenge. It remains intact after opening, except in front, where the adult insect has emerged. In shape it is a cylindrical bag, with firm, elastic walls. The segmentation is plainly visible. The magnifying-glass shows the fine star-shaped dots already ob- served in the Unarmed Zonitis. The stig- matic apertures have a projecting, dark-red rim. They are all, even the last, clearly marked. The signs of the legs are mere studs, hardly protruding, a little darker than the rest of the skin. The cephalic mask is reduced to a few mouldings which are not easy to distinguish. At the bottom of this pseudochrysalidal sheath I find a little white wad which, when placed in water, softened and then patiently unravelled with the tip of a paint-brush, yields a white, powdery substance, which is uric acid, the usual product of the work of 181 The Glow- Worm and Other Beetles the nymphosis, and a rumpled membrane, in which I recognize the cast skin of the nymph. There should still be the tertiary larva, of which I see not a trace. But, on taking a needle and gradually breaking the envelope of the pseudochrysalis, after soaking it awhile in water, I see it dividing into two layers, one an outer layer, brittle, horny in appearance and currant-red; the other an inner layer, consisting of a transparent, flex- ible pellicle. There can be no doubt that this inner layer represents the tertiary larva, whose skin is left adhering to the envelope of the pseudochrysalis. It is fairly thick and tough, but I cannot detach it except in shreds, so closely does it adhere to the horny, crumbly sheath. Since I possessed a fair number of pseudo- chrysalids, I sacrificed a few in order to ascer- tain their contents on the approach of the final transformations. Well, I never found anything that I could detach; I never suc- ceeded in extracting a larva in its tertiary form, though this larva is so easily obtained from the amber pouches of the Sitares and, in the Oil-beetles and Cerocomae, emerges of its own accord from the split wrapper of the pseudochrysalis. When, for the first time, the stiff shell encloses a body which 182 Cerocomae, Mylabres and Zonites does not adhere to the rest, this body is a nymph and nothing else. The wall sur- rounding it is a dull white inside. I at- tribute this colouring to the cast skin of the tertiary larva, which was inseparably fixed to the shell of the pseudochrysalis. The Zonites, therefore, display a pecu- liarity which is not offered by the other Meloidas, namely, a series of tightly-fitting shells, one within the other. The pseudo- chrysalis is enclosed in the skin of the sec- ondary larva, a skin which forms a pouch without an orifice, fitted very closely to its contents. The slough of the tertiary larva fits even more closely to the inner surface of the pseudochrysalid sheath. The nymph alone does not adhere to its envelope. In the Cerocomae and the Oil-beetles, each form of the hypermetamorphosis becomes detached from the preceding skin by a com- plete extraction; the contents are removed from the ruptured container and have no further connection with it. In the Sitares, the successive casts are not ruptured and re- main enclosed inside one another, but with an interval between, so that the tertiary larva can move and turn as it wishes in its multiple enclosure. In the Zonites, there is the same arrangement, with this difference, .183 The Glow-Worm and Other Beetles that, until the nymph appears, there is no empty space between one slough and the next. The tertiary larva cannot budge. It is not free, as witness its cast skin, which fits so precisely to the envelope of the pseudochrys- alis. This form would therefore pass un- perceived if its existence were not proclaimed by the membrane which lines the inside of the pseudochrysalid pouch. To complete the story of the Zonites, the primary larva is lacking. I do not yet know it, for, when rearing the insect under wire- gauze covers, I never succeeded in obtaining a batch of eggs. 184 CHAPTER VII THE CAPRICORN 1Y/TY youthful meditations owe some happy *•*•*• moments to Condillac's 1 famous sta- tue which, when endowed with the sense of smell, inhales the scent of a rose and out of that single impression creates a whole world of ideas. My twenty-year-old mind, full of faith in syllogisms, loved to follow the de- ductive jugglery of the abbe-philosopher: I saw, or seemed to see, the statue take life in that action of the nostrils, acquiring at- tention, memory, judgment and all the psy- chological paraphernalia, even as still waters are aroused and rippled by the impact of a grain of sand. I recovered from my illu- sion under the instruction of my abler mas- 1 Etienne Bonnot de Condillac, Abbe de Mureaux (1715-1780), the leading exponent of sensational philoso- phy. His most important work is the Traite des sensa- tions, in which he imagines a statue, organized like a man, and endows it with the senses one by one, begin- ning with that of smell. He argues by a process of imaginative reconstruction that all human faculties and all human knowledge are merely transformed sensation, to the exclusion of any other principle, that, in short, everything has its source in sensation: man is nothing but what he has acquired. — Translator's Note. 185 The Glow-Worm and Other Beetles ter, the animal. The Capricorn shall teach ITS that the problem is more obscure than the abbe led me to believe. When wedge and mallet are at work, pre- paring my provision of firewood under the grey sky that heralds winter, a favourite re- laxation creates a welcome break in my daily output of prose. By my express orders, the woodman has selected the oldest and most ravaged trunks in his stack. My tastes bring a smile to his lips; he wonders by what whimsy I prefer wood that is worm-eaten, chirouna, as he calls it, to sound wood, which burns so much better. I have my views on the subject; and the worthy man submits to them. And now to us two, O my fine oak-trunk seamed with scars, gashed with wounds whence trickle the brown drops smelling of the tan-yard. The mallet drives home, the wedges bite, the wood splits. What do your flanks contain? Real treasures for my studies. In the dry and hollow parts, groups of various insects, capable of living through the bad season of the year, have taken up their winter quarters : in the low-roofed gal- leries, galleries built by some Buprestis Bee- tle, Osmiae, working their paste of masticated leaves, have piled their cells one above the 1 86 The Capricorn other; in the deserted chambers and vesti- bules, Megachiles have arranged their leafy jars; in the live wood, filled with juicy saps, the larvae of the Capricorn (Cerambyx miles], the chief author of the oak's undo- ing, have set up their home. Strange creatures, of a verity, are these grubs, for an insect of superior organization: bits of intestines crawling about! At this time of year, the middle of autumn, I meet them of two different ages. The older are almost as thick as one's finger; the others hardly attain the diameter of a pencil. I find, in addition, pupae more or less fully coloured, perfect insects, with a distended abdomen, ready to leave the trunk when the hot weather comes again. Life inside the wood, therefore, lasts three years. How is this long period of solitude and captivity spent? In wandering lazily through the thickness of the oak, in making roads whose rubbish serves as food. The horse in Job swallows the ground 1 in a figure of speech; the Capricorn's grub eats its way literally. With its carpenter's-gouge, a strong black 1 " Chafing and raging, he swalloweth the ground, neither doth he make account when the noise of the trumpet soundeth." — Job, xxxix, 23 (Douai version). — Translator's Note. 187 The Glow-Worm and Other Beetles mandible, short, devoid of notches, scooped into a sharp-edged spoon, it digs the opening of its tunnel. The piece cut out is a mouth- ful which, as it enters the stomach, yields its scanty juices and accumulates behind the worker in heaps of wormed wood. The refuse leaves room in front by passing through the worker. A labour at once of nutrition and of road-making, the path is devoured while constructed; it is blocked be- hind as it makes way ahead. That, how- ever, is how all the borers who look to wood for victuals and lodging set about their busi- ness. For the harsh work of its two gouges, or curved chisels, the larva of the Capricorn concentrates its muscular strength in the front of its body, which swells into a pestle- head. The Buprestis-grubs, those other in- dustrious carpenters, adopt a similar form; they even exaggerate their pestle. The part that toils and carves hard wood requires a robust structure; the rest of the body, which has but to follow after, continues slim. The essential thing is that the implement of the jaws should possess a solid support and a powerful motor. The Cerambyx-larva strengthens its chisels with a stout, black, horny armour that surrounds the mouth ; yet, 188 The Capricorn apart from its skull and its equipment of tools, the grub has a skin as fine as satin and as white as ivory. This dead white comes from a copious layer of grease which the animal's spare diet would not lead us to sus- pect. True, it has nothing to do, at every hour of the day and night, but gnaw. The quantity of wood that passes into its stomach makes up for the dearth of nourishing ele- ments. The legs, consisting of three pieces, the first globular, the last sharp-pointed, are mere rudiments, vestiges. They are hardly a millimetre l long. For this reason, they are of no use whatever for walking; they do not even bear upon the supporting surface, being kept off it by the obesity of the chest. The organs of locomotion are something al- together different. The Cetonia-grub 2 has shown us how, with the aid of the hairs and the pad-like excrescences upon its spine, it manages to reverse the universally-accepted usage and to wriggle along on its back. The grub of the Capricorn is even more ingeni- ous: it moves at the same time on its back 1 .039 inch. — Translator's Note. 2 For the grub of the Cetonia, or Rose-chafer, cf. The Life and Love of the Insect, by J. Henri Fabre, translated by Alexander Teixeira de Mattos: chap. xi. — Translator' > Note. 189 The Glow-Worm and Other Beetles and belly; instead of the useless legs of the thorax, it has a walking-apparatus almost re- sembling feet, which appear, contrary to every rule, on the dorsal surface. The first seven segments of the abdomen have, both above and below, a four-sided facet, bristling with rough protuberances. This the grub can either expand or contract, making it stick out or lie flat at will. The upper facets consist of two excrescences sepa- rated by the mid-dorsal line; the lower ones have not this divided appearance. These are the organs of locomotion, the ambulacra. When the larva wishes to move forwards, it expands its hinder ambulacra, those on the back as well as those on the belly, and con- tracts its front ones. Fixed to the side of the narrow gallery by their ridges, the hind- pads give the grub a purchase. The flat- tening of the fore-pads, by decreasing the diameter, allows it to slip forward and to take half a step. To complete the step, the hind-quarters have to be brought up the same distance. With this object, the front pads fill out and provide support, while those be- hind shrink and leave free scope for their segments to contract. With the double support of its back and belly, with alternate puffings and shrinkings, 190 The Capricorn the animal easily advances or retreats along its gallery, a sort of mould which the con- tents fill without a gap. But, if the loco- motory pads grip only on one side, progress becomes impossible. When placed on the smooth wood of my table, the animal wrig- gles slowly; it lengthens and shortens with- out advancing by a hair's-breadth. Laid on the surface of a piece of split oak, a rough, uneven surface, due to the gash made by the wedge, it twists and writhes, moves the front part of its body very slowly from left to right and right to left, lifts it a little, lowers it and begins again. These are the most extensive movements made. The vestigial legs remain inert and absolutely useless. Then why are they there? Better to lose them altogether, if it be true that craw- ling inside the oak has deprived the animal of the good legs with which it started. The influence of environment, so well-inspired in endowing the grub with ambulatory pads, becomes a mockery when it leaves it these ridiculous stumps. Can the structure, per- chance, be obeying other rules than those of environment? Though the useless legs, the germs of the future limbs, persist, there is no sign in the grub of the eyes wherewith the Cerambyx 191 The Glow- Worm and Other Beetles will be richly gifted. The larva has not the least trace of organs of vision. What would it do with sight, in the murky thickness of a tree-trunk? Hearing is likewise absent. In the never-troubled silence of the oak's in- most heart, the sense of hearing would be a non-sense. Where sounds are lacking, of what use is the faculty of discerning them? Should there be any doubts, I will reply to them with the following experiment. Split lengthwise, the grub's abode leaves a half- tunnel wherein I can watch the occupant's doings. When left alone, it now gnaws the front of its gallery, now rests, fixed by its ambulacra to the two sides of the channel. I avail myself of these moments of quiet to enquire into its power of perceiving sounds. The banging of hard bodies, the ring of metallic objects, the grating of a file upon a saw are tried in vain. The animal remains impassive. Not a wince, not a move of the skin ; no sign of awakened attention. I suc- ceed no better when I scratch the wood close by with a hard point, to imitate the sound of some neighbouring larva gnawing the inter- vening thickness. The indifference to my noisy tricks could be no greater in a lifeless object. The animal is deaf. 192 The Capricorn Can it smell? Everything tells us no. Scent is of assistance in the search for food. But the Capricorn-grub need not go in quest of eatables : it feeds on its home, it lives on the wood that gives it shelter. Let us make an attempt or two, however. I scoop in a log of fresh cypress-wood a groove of the same diameter as that of the natural galleries and I place the worm inside it. Cypress- wood is strongly-scented ; it possesses in a high degree that resinous aroma which char- acterizes most of the pine family. Well, when laid in the odoriferous channel, the larva goes to the end, as far as it can go, and makes no further movement. Does not this placid quiescence point to the absence of a sense of smell? The resinous flavour, so strange to the grub which has always lived in oak, ought to vex it, to trouble it; and the disagreeable impression ought to be revealed by a certain commotion, by certain attempts to get away. Well, nothing of the kind hap- pens : once the larva has found the right po- sition in the groove, it does not stir. I do more : I set before it, at a very short distance, in its normal canal, a piece of camphor. Again, no effect. Camphor is followed by naphthaline. Still nothing. After these 193 The Glow- Worm and Other Beetles fruitless endeavours, I do not think that I am going too far when I deny the creature a sense of smell. Taste is there, no doubt. But such taste ! The food is without variety: oak, for three years at a stretch, and nothing else. What can the grub's palate appreciate in this mo- notonous fare ? The tannic relish of a fresh piece, oozing with sap; the uninteresting fla- vour of an over-dry piece, robbed of its na- tural condiment : these probably represent the whole gustative scale. There remains touch, the far-spreading passive sense common to all live flesh that quivers under the goad of pain. The sensi- tive schedule of the Cerambyx-grub, there- fore, is limited to taste and touch, both ex- ceedingly obtuse. This almost brings us to Condillac's statue. The imaginary being of the philosopher had one sense only, that of smell, equal in delicacy to our own; the real being, the ravager of the oak, has two, in- ferior, even when put together, to the former, which so plainly perceived the scent of a rose and distinguished it so clearly from any other. The real case will bear comparison with the fictitious. What can be the psychology of a creature possessing such a powerful digestive organ- 194 The Capricorn ism combined with such a feeble set of senses? A vain wish has often come to me in my dreams : it is to be able to think, for a few minutes, with the crude brain of my Dog, to see the world with the faceted eyes of a Gnat. How things would change in appearance ! They would change much more if interpreted by the intellect of the grub. What have the lessons of touch and taste contributed to that rudimentary receptacle of impressions? Very little; almost nothing. The animal knows that the best bits possess an astringent flavour; that the sides of a passage not carefully planed are painful to the skin. This is the utmost limit of its ac- quired wisdom. In comparison, the statue with the sensitive nostrils was a marvel of knowledge, a paragon too generously en- dowed by its inventor. It remembered, com- pared, judged, reasoned: does the drowsy, digesting paunch remember? Does it com- pare? Does it reason? I defined the Capri- corn-grub as a bit of an intestine that crawls about. The undeniable accuracy of this definition provides me with my answer: the grub has the aggregate of sense-impressions that a bit of an intestine may hope to have. And this nothing-at-all is capable of mar- vellous acts of foresight; this belly, which The Glow-Worm and Other Beetles knows hardly anything of the present, sees very clearly into the future. Let us take an illustration on this curious subject. For three years on end, the larva wanders about in the thick of the trunk; it goes up, goes down, turns to this side and that; it leaves one vein for another of better flavour, but without moving too far from the inner depths, where the temperature is milder and greater safety reigns. A day is at hand, a dangerous day for the recluse obliged to quit its excellent retreat and face the perils of the surface. Eating is not everything: we have to get out of this. The larva, so well- equipped with tools and muscular strength, finds no difficulty in going where it pleases, by boring through the wood; but does the coming Capricorn, whose short spell of life must be spent in the open air, possess the same advantages? Hatched inside the trunk, will the long-horned Beetle be able to clear itself a way of escape? That is the difficulty which the worm solves by inspiration. Less versed in things of the future, despite my gleams of reason, I re- sort to experiment with a view to fathoming the question. I begin by ascertaining that the Capricorn, when he wishes to leave the trunk, is absolutely unable to make use of 196 The Capricorn the tunnel wrought by the larva. It is a very long and very irregular maze, blocked with great heaps of wormed wood. Its dia- meter decreases progressively from the final blind alley to the starting-point. The larva entered the timber as slim as a tiny bit of straw; it is to-day as thick as one's finger. In its three years' wanderings, it always dug its gallery according to the mould of its body. Evidently, the road by which the larva entered and moved about cannot be the Capricorn's exit-way: his immoderate an- tennae, his long legs, his inflexible armour- plates would encounter an insuperable ob- stacle in the narrow, winding corridor, which would have to be cleared of its wormed wood and, moreover, greatly enlarged. It would be less fatiguing to attack the untouched tim- ber and dig straight ahead. Is the insect capable of doing so? We shall see. I make some chambers of suitable size in oak logs chopped in two; and each of my artificial cells receives a newly-transformed Cerambyx, such as my provisions of firewood supply, when split by the wedge, in October. The two pieces are then joined and kept to- gether with a few bands of wire. June comes. I hear a scraping inside my billets. Will the Capricorns come out, or not? The 197 The Glow-Worm and Other Beetles delivery does not seem difficult to me : there is hardly three-quarters of an inch to pierce. Not one emerges. When all is silence, I open my apparatus. The captives, from first to last, are dead. A vestige of saw- dust, less than a pinch of snuff, represents all their work. I expected more from those sturdy tools, their mandibles. But, as we have seen be- fore, the tool does not make the workman.1 In spite of their boring-implements, the her- mits die in my cases for lack of skill. I subject others to less arduous tests. I en- close them in spacious reed-stumps, equal in diameter to the natal cell. The obstacle to be pierced is the natural diaphragm, a yield- ing partition two or three millimetres 2 thick. Some free themselves; others cannot. The less valiant ones succumb, stopped by the frail barrier. What would it be if they had to pass through a thickness of oak? We are now persuaded: despite his stal- wart appearance, the Capricorn is powerless 1 Cf. The Life and Love of the Insect: chap. iii. " The tool does not make the workman. The insect exerts its gifts as a specialist with any kind of tool wherewith it is supplied. It can saw with a plane or plane with a saw, like the model workman of whom Franklin tells us." — Translator's Note. 2 .078 to .117 inch. — Translator's Note. 198 The Capricorn to leave the tree-trunk by his unaided efforts. It therefore falls to the worm, to the wisdom of that bit of an intestine, to prepare the way for him. We see renewed, in another form, the feats of prowess of the Anthrax, whose pupa, armed with trepans, bores through rock on the feeble Fly's behalf. Urged by a presentiment that to us remains an un- fathomable mystery, the Cerambyx-grub leaves the inside of the oak, its peaceful re- treat, its unassailable stronghold, to wriggle towards the outside, where lives the foe, the Woodpecker, who may gobble up the suc- culent little sausage. At the risk of its life, it stubbornly digs and gnaws to the very bark, of which it leaves no more intact than the thinnest film, a slender screen. Sometimes, even, the rash one opens the window wide. This is the Capricorn's doorway. The insect will have but to file the screen a little with its mandibles, to bump against it with its forehead, in order to bring it down; it will even have nothing to do when the win- dow is free, as often happens. The un- skilled carpenter, burdened with his extrava- gant head-dress, will emerge from the dark- ness through this opening when the summer heats arrive. After the cares of the future come the 199 The Glow-Worm and Other Beetles cares of the present. The larva, which has just opened the aperture of escape, retreats some distance down its gallery and, in the side of the exit-way, digs itself a transforma- tion-chamber more sumptuously furnished and barricaded than any that I have ever seen. It is a roomy niche, shaped like a flattened ellipsoid, the length of which reaches some eighty to a hundred millimetres.1 The two axes of the cross-section vary: the hori- zontal measures twenty-five to thirty milli- metres2; the vertical measures only fifteen.1' This greater dimension of the cell, where the thickness of the perfect insect is concerned, leaves a certain scope for the action of its legs when the time comes for forcing the barricade, which is more than a close-fitting mummy-case would do. The barricade in question, a door which the larva builds to exclude the dangers from without, is two- and even three-fold. Out- side, it is a stack of woody refuse, of par- ticles of chopped timber; inside,, a 'mineral hatch, a concave cover, all in one piece, of a chalky white. Pretty often, but not always, there is added to these two layers ah inner 1 3 to 4 inches. — Translator's Note. 2 -975 to 1.17 inch. — Translator's Note. * .585 inch. — Translator's Note. The Capricorn casing of shavings. Behind this compound door, the larva makes its arrangements for the metamorphosis. The sides of the cham- ber are rasped, thus providing a sort of down formed of ravelled woody fibres, broken into minute shreds. The velvety matter, as and when obtained, is applied to the wall in a continuous felt at least a millimetre thick.1 The chamber is thus padded throughout with a fine swan's-down, a delicate precaution taken by the rough worm on behalf of the tender pupa. Let us hark back to the most curious part of the furnishing, the mineral hatch or inner door of the entrance. It is an elliptical skull-cap, white and hard as chalk, smooth within and knotted without, resembling more or less closely an acorn-cup. The knots show that the matter is supplied in small, pasty mouthfuls, solidifying outside in slight projections which the animal does not re- move, being unable to get at them, and pol- ished on the inside surface, which is within the worm's reach. What can be the nature of that singular lid whereof the Cerambyx furnishes me with the first specimen? It is as hard and brittle as a flake of lime-stone. It can be dissolved cold in nitric acid, dis-> 1 .oj9 inch. — Translator's Note. 201 The Glow- Worm and Other Beetles charging little gaseous bubbles. The process of solution is a slow one, requiring several hours for a tiny fragment. Everything is dissolved, except a few yellowish flocks, which appear to be of an organic nature. As a matter of fact, a piece of the lid, when subjected to heat, blackens, which proves the presence of an organic glue cementing the mineral matter. The solution becomes muddy if oxalate of ammonia be added and deposits a copious white precipitate. These signs indicate calcium carbonate. I look for urate of ammonia, that constantly-recurring product of the various stages of the meta- morphoses. It is not there: I find not the least trace of murexide. The lid, therefore, is composed solely of carbonate of lime and of an organic cement, no doubt of an al- buminous character, which gives consistency to the chalky paste. Had circumstances served me better, I should have tried to discover in which of the worm's organs the stony deposit dwells. I am, however, convinced: it is the stomach, the chylific ventricle, that supplies the chalk. It keeps it separate from the food, either as original matter or as a derivative of the ammonium urate; it purges it of all foreign bodies, when the larval period comes to an The Capricorn end, and holds it in reserve until the time comes to disgorge it. This freestone-fac- tory causes me no astonishment: when the manufacturer undergoes his change, it serves for various chemical works. Certain Oil- beetles, such as the Sitaris, locate in it the urate of ammonia, the refuse of the trans- formed organism; the Sphex, the Pelopaei, the Scoliae,1 use it to manufacture the shellac wherewith the silk of the cocoon is varnished. Further investigations will only swell the ag- gregate of the products of this obliging or- gan. When the exit-way is prepared and the cell upholstered in velvet and closed with a three- fold barricade, the industrious worm has con- cluded its task. It lays aside its tools, sheds its skin and becomes a nymph, a pupa, weak- ness personified, in swaddling-clothes, on a soft couch. The head is always turned to- wards the door. This is a trifling detail in appearance; but it is everything in reality. To lie this way or that in the long cell is a matter of great indifference to the worm, which is very supple, turning easily in its narrow lodging and adopting whatever po- sition it pleases. The coming Capricorn will not enjoy the same privileges. Stiffly girt in 1 Three species of Digger-wasps. — Translator's Note. 203 The Glow-Worm and Other Beetles his horn cuirass, he will not be able to turn from end to end; he will not even be capable of bending, if some sudden wind should make the passage difficult. He must absolutely find the door in front of him, lest he perish in the casket. Should the grub forget this little formality, should it lie down to its nymphal sleep with its head at the back of the cell, the Capricorn is infallibly lost : his cradle becomes a hopeless dungeon. But there is no fear of this danger: the knowledge of the bit of an intestine is too sound in things of the future for the grub to neglect the formality of keeping its head to the door. At the end of spring, the Cap- ricorn, now in possession of his full strength, dreams of the joys of the sun, of the festivals of light. He wants to get out. What does he find before him? A heap of filings easily dispersed with his claws ; next, a stone lid which he need not even break into fragments : it comes undone in one piece; it is removed from its frame with a few pushes of the fore- head, a few tugs of the claws. In fact, I find the lid intact on the threshold of the aban- doned cells. Last conies a second mass of woody remnants as easy to disperse as the first. The road is now free : the Cerambyx has but to follow the spacious vestibule, 204 The Capricorn which will lead him, without the possibility of mistake, to the exit Should the window not be open, all that he has to do is to gnaw through a thin screen: an easy task; and be- hold him outside, his long antennae aquiver with excitement. What have we learnt from him ? Nothing from him ; much from his grub. This grub, so poor in sensory organs, gives us with its prescience no little food for reflection. It knows that the coming Beetle will not be able to cut himself a road through the oak and it bethinks itself of opening one for him at its own risk and peril. It knows that the Cerambyx, in his stiff armour, will never be able to turn and make for the orifice of the cell; and it takes care to fall into its nymphal sleep with its head to the door. It knows how soft the pupa's flesh will be and up- holsters the bedroom with velvet. It knows that the enemy is likely to break in during the slow work of the transformation and, to set a bulwark against his attacks, it stores a calcium pap inside its stomach. It knows the future with a clear vision, or, to be ac- curate, behaves as though it knew the future. Whence did it derive the motives of its ac- tions? Certainly not from the experience of the senses. What does it know of the 205 The Glow- Worm and Other Beetles outside world? Let us repeat, as much as a bit of an intestine can know. And this sense- less creature astounds us ! I regret that the clever logician, instead of conceiving a statue smelling a rose, did not imagine it gifted with some instinct. How quickly he would have recognized that, quite apart from sense-im- pressions, the animal, including man, pos- sesses certain psychological resources, certain inspirations that are innate and not acquired! 206 CHAPTER VIII THE PROBLEM OF THE SIREX r I "HE cherry-tree supports a small jet- ••• black Capricorn, Cerambyx cerdo, whose larval habits it was as well to study in order to learn whether the instincts are modified when the form and the organization remain identical. Has this pigmy of the family the same talents as the giant, the ravager of the oak-tree? Does it work on the same principles? The resemblance be- tween the two, both in the larval state and in that of the perfect insect, is complete; the denizen of the cherry-tree is an exact replica, on a smaller scale, of the denizen of the oak. If instinct is the inevitable consequence of the organism, we ought to find in the two in- sects a strict similarity of habits; if instinct is, on the other hand, a special aptitude fa- voured by the organs, we must expect va- riations in the industry exercised. For the second time the alternative is forced upon our attention: do the implements govern the practice of the craft, or does the craft gov- ern the employment of the implements? Is 207 The Glow- Worm and Other Beetles instinct derived from the organ, or is the or- gan instinct's servant? An old dead cherry- tree will answer our question. Beneath its ragged bark, which I lift in wide strips, swarms a population of larvae all belonging to Cerambyx cerdo. There are big larvae and little larvae; moreover, they are accompanied by nymphs. These details tell us of three years of larval existence, a duration of life frequent in the Longicorn series. If we hunt the thick of the trunk, splitting it again and again, it does not show us a single grub anywhere; the entire popu- lation is encamped between the bark and the wood. Here we find an inextricable maze of winding galleries, crammed with packed sawdust, crossing, recrossing, shrinking into little alleys, expanding into wide spaces and cutting, on the one hand, into the surface layer of the sap-wood and, on the other, into the thin sheets of the inner bark. The po- sition speaks for itself: the larva of the little Capricorn has other tastes than its large kins- man's; for three years it gnaws the outside of the trunk beneath the thin covering of the bark, while the other seeks a deeper refuge and gnaws the inside. The dissimilarity is yet more marked in the preparations for the nymphosis. Then 208 The Problem of the Sirex the worm of the cherry-tree leaves the sur- face and penetrates into the wood to a depth of about two inches, leaving behind it a wide passage, which is hidden on the outside by a remnant of bark that has been discreetly spared. This spacious vestibule is the fu- ture insect's path of release; this screen of bark, easily destroyed, is the curtain that masks the exit-door. In the heart of the wood the larva finally scoops out the cham- ber destined for the nymphosis. This is an egg-shaped recess an inch and a quarter to an inch and three-quarters in length by two- fifths of an inch in diameter. The walls are bare, that is to say, they are not lined with the blanket of shredded fibres dear to the Capricorn of the Oak. The entrance is blocked first by a plug of fibrous sawdust, then by a chalky lid, similar, except in point of size, to that with which we are already familiar. A thick layer of fine sawdust packed into the concavity of the chalky lid, completes the barricade. Need I add that the grub lies down and goes to sleep, for the nymphosis, with its head against the door? Not one forgets to take this precaution. The two Capricorns have, in short, the same system of closing their cells. Note above all the lens-shaped stony lid. In each 209 The Glow- Worm and Other Beetles case we find the same chemical composition, the same formation, like the cup of an acorn. Dimensions apart, the two structures are identical. But no other genus of Longicorn, so far as I am aware, practises this craft. I will therefore complete the classic descrip- tion of the Cerambyx-beetles by adding one characteristic : they seal their metamorphosis- chambers with a chalk slab. The similarities of habit go no farther, despite the identity of structure. There is even a very sharp contrast between the meth- ods pursued. The Capricorn of the Oak in- habits the deep layers of the trunk; the Cap- ricorn of the Cherry-tree inhabits the sur- face. In the preparations for the trans- formation, the first ascends from the wood to the bark, the second descends from the bark to the wood; the first risks the perils of the outer world, the second shuns them and seeks a retreat inside. The first hangs the walls of its chamber with velvet, the second knows nothing of this luxury. Though the work is almost the same in its results, it is at least carried out by contrary methods. The tool, therefore, does not govern the trade. This is what the two Cerambyx- beetles tell us. Let us vary, the testimony of the Longi- The Problem of the Sirex corns. I am not selecting; I am recording it in the order of my discoveries. The Shagreen Saperda (5. carcharias) lives in the black poplar; the Scalary Saperda (S. scalarls) lives in the cherry-tree. In both we find the same organization and the same implements, as is fitting in two closely-re- lated species. The Saperda of the Poplar adopts the method of the Capricorn of the Oak in its general features. It inhabits the interior of the trunk. On the approach of the transformation, it makes an exit-gallery, the door of which is open or else masked by a remnant of bark. Then, retracing its steps, it blocks the passage with a barricade of coarse packed shavings; and, at a depth of about eight inches, not far from the heart of the tree, it hollows out a cavity for the nymphosis without any particular upholster- ing. The defensive system is limited to the long column of shavings. To deliver itself, the insect will only have to push the heap of woody rubbish back, in so many lots; the path will open in front of it ready-made. If some screen of bark hide the gallery from the outside, its mandibles will easily dispose of that: it is soft and not very thick. The Scalary Saperda imitates the habits of its messmate, the Capricorn of the Cherry- The Glow- Worm and Other Beetles tree. Its larva lives between the wood and the bark. To undergo its transformation, it goes down instead of coming up. In the sap-wood, parallel with the surface of the trunk, under a layer of wood barely a twenty- fifth of an inch in thickness, it makes a cylin- drical cell, rounded at the ends and roughly padded with ligneous fibres. A solid plug of shavings barricades the entrance, which is not preceded by any vestibule. Here the work of deliverance is the simplest. The Saperda has only to clear the door of his chamber to find beneath his mandibles the little bit of bark that remains to be pierced. As you see, we once more have to do with two specialists, each working in his own man- ner with the same tools. The Buprestes, as zealous as the Longi- corns in the destruction of trees, whether sound or ailing, tell us the same tale as the Cerambyx- and Saperda-beetles. The Bronze Buprestis (B.