But suppose that this diet varies, that the environment in which they are called upon to live changes, that the circumstances accompanying their development are liable to great changes: it then becomes evident that the moult may and even must adapt the organization of the larva to these new conditions of existence. The primary larva of the Sitaris lives on the body of the Anthophora. 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 proceeds 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 on a sticky fluid; instead of living in broad daylight, it has to remain plunged in the profoundest 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 disappear 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 integuments, its ocelli, being no longer necessary in a dark cell where movement is impossible, where there are no rough encounters to be feared, may likewise give place to complete blindness, to soft integuments, to a heavy, slothful form. This transfiguration, which everything shows to be indispensable 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 abnormal 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 future. The larva of the Meloidae, therefore, undergo four moults before attaining the nymphal state; and after each moult their characteristics alter most profoundly. During all these external changes, the internal 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 reproductive 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 perfect 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 suggest that of hypermetamorphosis.

Let us now recapitulate the more prominent facts of this essay.

The Sitares, the Meloes, the Zonites and apparently other Meloidae, possibly all of them, are in their earliest infancy parasites of the harvesting Bees.

The larva of the Meloidae, before reaching 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 external characteristics. It feeds upon the honey contained in the usurped cell.

The pseudochrysalis is a body deprived of all movement and clad in horny integuments which may be compared with those of the pupae and chrysalids. On these integuments we see a cephalic mask without distinct or movable parts, six tubercles indicating 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 exactly the peculiarities of the second; it is enclosed, 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 integuments 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.



CHAPTER VI CEROCOMAE, 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 themselves carried into the cell where they will destroy the egg and afterwards feed upon the ration of honey. A most unexpected 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 generalization. Many have accepted it without 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 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 16th of July, 1883, I was digging, with my son Emile, 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 assuaged; 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 is!"

Then, suddenly turning to Emile, who was rather surprised by this soliloquy:

"My boy," I said, "you have had a magnificent find. It's a pseudochrysalis of the Meloidae. It's a document of incalculable value; you've struck a fresh vein in the extraordinary 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 pseudochrysalis 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 comes 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 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 future, 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 motionless, 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 segments 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 on the line dividing it from the first segment. Then follow eight pairs, one on each segment 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 corresponds with the mandibles. The length of this organism varies greatly, fluctuating between 8 and 15 millimetres.[1] Its width is from 3 to 4 millimetres.[2]

[Footnote 1: .312 to .585 inch.—Translator's Note.]

[Footnote 2: .117 to .156 inch.—Translator's Note.]

Apart from the general configuration, it will be seen that we have here the strikingly characteristic appearance of the pseudochrysalids of the Sitares, Oil-beetles and Zonites. There are the same rigid integuments, 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 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.[3] If we reduce the dimensions considerably, we shall have something very like the parasite of the Tachytes.

[Footnote 3: It was his essays in this periodical, on the metamorphoses of the Sitares and Oil-beetles, that procured Fabre his first reputation as an entomologist.—Translator's Note.]

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 definite grooves. The first thoracic segment is a little longer than the rest, with the dorsal 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 stigmata on the mesothorax, near the line of junction with the prothorax; a stigma on either side of the first eight abdominal segments; in all nine pairs of stigmata, distributed 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, 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 assistance; 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 discovered 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 devouring the ration of the Anthophora.

I imagine that, in the burrows of the 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.[4] The smaller rations certainly fall to the males, which are puny dwarfs compared with their companions; the more plentiful fall to the females. The parasitic grub to which fate has allotted the scanty masculine ration has not perhaps sufficient with this share; it wants an extra portion, which it can obtain by changing its cell. If it be favoured by chance, it will eat according to the measure of its hunger and will attain the full development 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.

[Footnote 4: 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.]

During the active period, the larva undergoes 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 another 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 additional food as long as it accepted it, stops eating at last. It becomes motionless, retracts 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 appears 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 future legs and mouth-parts. This shedding 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 pseudochrysalis 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 outset 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 carnivorous Meloid. It is nevertheless very remarkable to find in the Blister-beetles, on both sides of the Atlantic, this weakness for the flavour of Locust: one devours her eggs; the 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.[5] I submit the question to whom it may concern.

[Footnote 5: The essays on these will appear in the volume, entitled The Hunting Wasps, aforementioned.—Translator's Note.]

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. It is active and wriggles with awkward movements. 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, consisting 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 movable 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, transparent, without a terminal claw. They are three-jointed stumps. Pale stigmata, eight pairs of them, placed as in the pseudochrysalis, 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 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 magnifying-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 describing. 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 pseudochrysalis as a sort of egg of a superior organization, 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, makes the Meloid go through the larval dimorphism of the Anthrax and the Leucospis. The primary larva finds its way to the victuals; the secondary larva consumes them. The second hatching, that of the pseudochrysalis, 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 duration, 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 without 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 exposed 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 placed the pseudochrysalids that remained on a layer of fresh sand at the bottom of a glass receiver. Direct exposure to the sun was impracticable: 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 attempts at heating would be fruitless, I replaced the pseudochrysalids in the shade, on the shelves, in glass tubes. Here they passed a second year, still in the same condition.

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 obtaining shrivelled, like those of the year before. Will these two failures, arising no doubt from the overdry atmosphere of my receivers, conceal from us the genus and the species of the Mantis-eating Meloid? Fortunately, 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 Iles d'Hyeres everlasting. This last date is best-suited to explain the presence of the parasitic larva and its pseudochrysalis in the Tachytes' burrows from July onwards. Moreover, the Cerocoma 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 Mylabris, therefore, must be eliminated; the antennae, in the nymph, must be regularly jointed, as they are in the perfect insect. There remains the Cerocoma.

Any lingering doubts may be dispelled: by good fortune, a friend of mine, Dr. Beauregard, who is preparing a masterly work upon the Blister-beetles, had some pseudochrysalids of Schreber's Cerocoma in his possession. Having visited Serignan for the purpose 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 attempts, 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 between the two organisms. Everything therefore confirms the supposition that my discovery can relate only to Schaeffer's Cerocoma. As for the other, it must be eliminated: its extreme rarity in my neighbourhood is a sufficient reason.

It is tiresome that the diet of the Aramon Meloid is not known. If I allowed myself to be guided by analogy, I should be inclined 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 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 Cerocoma, of whom I find plenty, in the spring, on the blossoms of the everlasting. Whenever I see it, my attention is attracted by an unusual peculiarity: the great difference of size that is able to exist between one specimen 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 another. The grub that does not eat its fill remains small, while the one that gluts itself grows fat. These differences of size, in themselves, betray parasitism. If a mother's pains had amassed the food, or if the family had had the industry to obtain it direct instead 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 history 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 seeking among the Meloidae of my neighbourhood for the size that corresponded with the pseudochrysalids unearthed from the 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 consult, 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. biluminosa), of which the insect nibbles only the corollae. For the Twelve-spotted Mylabris, I provide blossoms of the scabious (Scabiosa maritima); for the Zonitis, the full-blown heads of the eryngo (Eryngium campestre); for Schaeffer's Cerocoma, the heads of the Iles d'Hyeres everlasting (Helichrysum stoechas). 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 creation. 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, 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 nibbling 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 victim. While the blows fall thick as hail, in front and behind, the head and corselet of the amorous swain are shaken by an extravagant 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 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 undisturbed 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 antennae. 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 reins in both hands. Thus mastering his mount, he is sometimes motionless and sometimes 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 unfeeling 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 outstretched like the limbs of a cross. At brief intervals the amorous outbursts, with blows conscientiously distributed, recur in alternation with periods of repose, during which the male holds his fore-legs crosswise, or else masters the female by the bridle of her antennae. 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 heroic 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, wherever she pleases, so that she may choose the bit of green stuff to her taste. Sometimes he also takes a gallant resolve and, like the female, 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 complicated, 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 insects form couples on the bunch of everlastings. Hoisted on the female, whom he embraces 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 moreover 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.

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 flagellatory twirl. She innocently curls her antennae. The rejected suitor leaves her and moves on to another. His dizzy, twirling passes, his protestations are everywhere refused. 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 refused 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, sometimes even a fourth, and mounts upon the heap of his predecessors. The uppermost 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 vibrations 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 expeditious in their preliminaries, so much 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 next closed. The mother sweeps up the rubbish 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 working. When this layer is well packed, she starts raking together fresh material to complete 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 bindweed 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 return 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 through her mandibles, then moves away and climbs to the top of the dome without attempting 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 newborn animalcule amazes us with its foresight; the adult insect astonishes us with its stupidity.

With both Mylabres, the batch consists of some forty eggs, a very small number compared 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 underground lodging. The eggs of the Twelve-spotted Mylabris are white, cylindrical, rounded at both ends and measure a millimetre and a half in length by half a millimetre in width.[6] Those of the Four-spotted Mylabris are straw coloured and of an elongated oval, a trifle fuller at one end than at the other. Length, two millimetres; width, a little under one millimetre.[7]

[Footnote 6: .058 x .019 inch.—Translator's Note.]

[Footnote 7: .078 x .039 inch.—Translator's Note.]

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 September. 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.[8] Coming out of a good-sized egg, it is endowed with greater vigour than the larvae of the Sitares and Oil-beetles. The head is large, rounded, slightly wider than the prothorax and of a rather brighter red. Mandibles 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, with three joints, the last thinner and pointed. Palpi very much pronounced.

[Footnote 8: .078 inch.—Translator's Note.]

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 smallness. 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 and olive brown. All the brown rings bristle with short, sparse hairs. The anal segment, which is narrower than the rest, bears at the tip two long cirri, very fine, slightly waved and almost as long as the whole abdomen.

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 blossom in order to slip into the fleece of a harvesting 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,[9] 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.

[Footnote 9: Cf. Bramble-bees and Others: chaps. xii. to xiv.—Translator's Note.]

The primary larva of the Mylabris therefore 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 seeking 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 primary larva of the Oil-beetle, for instance, settles on any insect that happens to pay a momentary visit to the flower in which the tiny creature is on the look-out. Whether this visitor be hairy or smooth-skinned, a manufacturer 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 depends 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 innumerable family. The Oil-beetle's batch of eggs is prodigious. Prodigious too is that of the Sitaris, who is exposed to similar misadventures.

If, with her thirty or forty eggs, the Mylabris 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 burrows containing food. The little creature's sturdy legs allow of these underground investigations. 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 competitors, 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 ripping open and drinking the contents of the Anthophora's egg, the Meloid, now the sole possessor of the victuals, doffs its battle array and becomes the pot-bellied grub, the consumer of the property so brutally acquired. These are merely suspicions on my part, nothing more. Direct observation will, I believe, confirm them, so close is their connection 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. praeusta. I have spoken of the first in another volume;[10] 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 adding its quota of evidence to a story which is still very incomplete. I have obtained the Burnt Zonitis, in the first place, from the cotton pouches of Anthidium scapulare, who, like the Three-toothed Osmia, makes her nests in the brambles; in the second place, from the wallets of Megachile sericans, made with little round disks of the leaves of the common acacia; in the third place, from the cells which Anthidium bellicosum[11] builds with partitions 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.

[Footnote 10: Cf. Bramble-bees and Others: chaps. i., iii. and x.—Translator's Note.]

[Footnote 11: For the Cotton-bee, Leaf-cutter and Resin-bee mentioned, cf. Bramble-bees and Others: passim.—Translator's Note.]

During the last fortnight of July, I witness the emergence of the Burnt Zonitis from the pseudochrysalis. The latter is cylindrical, 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 abdominal stigmata; they are round and diminish 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 was soft, white, big-bellied, blind, with rudimentary 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 pseudochrysalis 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 observed in the Unarmed Zonitis. The stigmatic 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 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, flexible 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 pseudochrysalids, I sacrificed a few in order to ascertain their contents on the approach of the final transformations. Well, I never found anything that I could detach; I never succeeded 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 does not adhere to the rest, this body is a nymph and nothing else. The wall surrounding it is a dull white inside. I attribute 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 peculiarity which is not offered by the other Meloidae, namely, a series of tightly-fitting shells, one within the other. The pseudochrysalis is enclosed in the skin of the secondary 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 complete 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 remain 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, 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 pseudochrysalis. This form would therefore pass unperceived 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.



CHAPTER VII THE CAPRICORN

My youthful meditations owe some happy moments to Condillac's[1] famous statue 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 deductive jugglery of the abbe-philosopher: I saw, or seemed to see, the statue take life in that action of the nostrils, acquiring attention, memory, judgment and all the psychological paraphernalia, even as still waters are aroused and rippled by the impact of a grain of sand. I recovered from my illusion under the instruction of my abler master, the animal. The Capricorn shall teach us that the problem is more obscure than the abbe led me to believe.

[Footnote 1: Etienne Bonnot de Condillac, Abbe de Mureaux (1715-1780), the leading exponent of sensational philosophy. His most important work is the Traite des sensations, in which he imagines a statue, organized like a man, and endows it with the senses one by one, beginning 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.]

When wedge and mallet are at work, preparing my provision of firewood under the grey sky that heralds winter, a favourite relaxation 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 galleries, galleries built by some Buprestis Beetle, Osmiae, working their paste of masticated leaves, have piled their cells one above the other; in the deserted chambers and vestibules, 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 undoing, 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[2] in a figure of speech; the Capricorn's grub eats its way literally. With its carpenter's-gouge, a strong black mandible, short, devoid of notches, scooped into a sharp-edged spoon, it digs the opening of its tunnel. The piece cut out is a mouthful 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 behind as it makes way ahead. That, however, is how all the borers who look to wood for victuals and lodging set about their business.

[Footnote 2: "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.]

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 industrious 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, 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 suspect. 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 elements.

The legs, consisting of three pieces, the first globular, the last sharp-pointed, are mere rudiments, vestiges. They are hardly a millimetre[3] 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 altogether different. The Cetonia-grub[4] 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 ingenious: it moves at the same time on its back and belly; instead of the useless legs of the thorax, it has a walking-apparatus almost resembling feet, which appear, contrary to every rule, on the dorsal surface.

[Footnote 3: .039 inch.—Translator's Note.]

[Footnote 4: 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's Note.]

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 separated 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 contracts its front ones. Fixed to the side of the narrow gallery by their ridges, the hind-pads give the grub a purchase. The flattening 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 behind shrink and leave free scope for their segments to contract.

With the double support of its back and belly, with alternate puffings and shrinkings, the animal easily advances or retreats along its gallery, a sort of mould which the contents fill without a gap. But, if the locomotory pads grip only on one side, progress becomes impossible. When placed on the smooth wood of my table, the animal wriggles slowly; it lengthens and shortens without 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 crawling 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, perchance, 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 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 inmost 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 succeed no better when I scratch the wood close by with a hard point, to imitate the sound of some neighbouring larva gnawing the intervening thickness. The indifference to my noisy tricks could be no greater in a lifeless object. The animal is deaf.

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 characterizes 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 happens: once the larva has found the right position 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 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 monotonous fare? The tannic relish of a fresh piece, oozing with sap; the uninteresting flavour of an over-dry piece, robbed of its natural 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 sensitive schedule of the Cerambyx-grub, therefore, is limited to taste and touch, both exceedingly 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, inferior, 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 organism 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 acquired wisdom. In comparison, the statue with the sensitive nostrils was a marvel of knowledge, a paragon too generously endowed by its inventor. It remembered, compared, judged, reasoned: does the drowsy, digesting paunch remember? Does it compare? Does it reason? I defined the Capricorn-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 marvellous acts of foresight; this belly, which 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 resort 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 the tunnel wrought by the larva. It is a very long and very irregular maze, blocked with great heaps of wormed wood. Its diameter 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 antennae, his long legs, his inflexible armour-plates would encounter an insuperable obstacle 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 timber 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 together with a few bands of wire. June comes. I hear a scraping inside my billets. Will the Capricorns come out, or not? The 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 sawdust, less than a pinch of snuff, represents all their work.

I expected more from those sturdy tools, their mandibles. But, as we have seen before, the tool does not make the workman.[5] In spite of their boring-implements, the hermits die in my cases for lack of skill. I subject others to less arduous tests. I enclose them in spacious reed-stumps, equal in diameter to the natal cell. The obstacle to be pierced is the natural diaphragm, a yielding partition two or three millimetres[6] 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?

[Footnote 5: 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.]

[Footnote 6: .078 to .117 inch.—Translator's Note.]

We are now persuaded: despite his stalwart appearance, the Capricorn is powerless 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 unfathomable mystery, the Cerambyx-grub leaves the inside of the oak, its peaceful retreat, its unassailable stronghold, to wriggle towards the outside, where lives the foe, the Woodpecker, who may gobble up the succulent 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 window is free, as often happens. The unskilled carpenter, burdened with his extravagant head-dress, will emerge from the darkness through this opening when the summer heats arrive.

After the cares of the future come the 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 transformation-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.[7] The two axes of the cross-section vary: the horizontal measures twenty-five to thirty millimetres;[8] the vertical measures only fifteen.[9] 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.

[Footnote 7: 3 to 4 inches.—Translator's Note.]

[Footnote 8: .975 to 1.17 inch.—Translator's Note.]

[Footnote 9: .585 inch.—Translator's Note.]

The barricade in question, a door which the larva builds to exclude the dangers from without, is two- and even three-fold. Outside, it is a stack of woody refuse, of particles 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 an inner casing of shavings. Behind this compound door, the larva makes its arrangements for the metamorphosis. The sides of the chamber 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.[10] 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.

[Footnote 10: .039 inch.—Translator's Note.]

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 remove, being unable to get at them, and polished 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, discharging 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 metamorphoses. 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 albuminous 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 end, and holds it in reserve until the time comes to disgorge it. This freestone-factory 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 transformed organism; the Sphex, the Pelopaei, the Scoliae,[11] use it to manufacture the shellac wherewith the silk of the cocoon is varnished. Further investigations will only swell the aggregate of the products of this obliging organ.

[Footnote 11: Three species of Digger-wasps.—Translator's Note.]

When the exit-way is prepared and the cell upholstered in velvet and closed with a three-fold barricade, the industrious worm has concluded its task. It lays aside its tools, sheds its skin and becomes a nymph, a pupa, weakness personified, in swaddling-clothes, on a soft couch. The head is always turned towards 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 position it pleases. The coming Capricorn will not enjoy the same privileges. Stiffly girt in 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 Capricorn, 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 forehead, a few tugs of the claws. In fact, I find the lid intact on the threshold of the abandoned cells. Last comes 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, 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 behold 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 upholsters 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 accurate, behaves as though it knew the future. Whence did it derive the motives of its actions? Certainly not from the experience of the senses. What does it know of the 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-impressions, the animal, including man, possesses certain psychological resources, certain inspirations that are innate and not acquired!



CHAPTER VIII THE PROBLEM OF THE SIREX

The 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 between 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 insects a strict similarity of habits; if instinct is, on the other hand, a special aptitude favoured by the organs, we must expect variations 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 govern the employment of the implements? Is instinct derived from the organ, or is the organ 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 population 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 position speaks for itself: the larva of the little Capricorn has other tastes than its large kinsman'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 the worm of the cherry-tree leaves the surface 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 future 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 chamber 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 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 description 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 methods pursued. The Capricorn of the Oak inhabits the deep layers of the trunk; the Capricorn of the Cherry-tree inhabits the surface. In the preparations for the transformation, 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 Longicorns. I am not selecting; I am recording it in the order of my discoveries. The Shagreen Saperda (S. carcharias) lives in the black poplar; the Scalary Saperda (S. scalaris) lives in the cherry-tree. In both we find the same organization and the same implements, as is fitting in two closely-related 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 upholstering. 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-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 cylindrical 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 manner with the same tools.