THE BULL ONTHOPHAGUS: THE LARVA; THE NYMPH

May is the nesting-month of the different Onthophagi and of the Bull Onthophagus in particular. The mothers now go underground to some little depth, under the shelter of the cave whence the building and victualling-materials are extracted. Unaided by the males, who, heedless of family cares, continue to lead a life of jollity, they fashion their cabins and stuff them with provisions after the egg is laid. The work, for that matter, is crude and elementary and hardly needs the collaboration of the horned dandies. Five or six establishments at most, each founded in a couple of days, represent the whole of a mother’s work and leave plenty of time for spring revelry.

The grub is hatched in about a week; and a strange and paradoxical little creature it is. On its back it has an enormous sugar-loaf hump, the weight of which overbalances it each time that it tries to stand on its legs and walk. At every moment it staggers and falls under the burden of the hunch. The Sacred Beetle’s larva showed us long ago a knapsack which was a storehouse of cement to stop up the accidental cracks in the provision-box and protect the food from drying too rapidly. The Onthophagus’ grub exaggerates a similar [281]warehouse to the utmost degree; it makes a cone-shaped monument of it, so extravagant and grotesque as to border on caricature. Is it some mad masquerader’s joke or a rational deformity which will have its uses later? The future will tell us.

Without saying anything more about it, for lack of words to give a picture of anything so extraordinary, I will refer the reader to the grub of the Oniticellus, which I sketched in an earlier chapter.1 The two hunchbacks are very much alike.

Unable to keep its hump upright, the grub of the Onthophagus lies down on its side in the cell and licks the cream all around it. There is cream everywhere, on the ceiling, on the walls, on the floor. As soon as one spot is thoroughly bared, the consumer moves a little way on with the help of its well-shaped legs; it capsizes again and starts licking again. As the cabin is large and plentifully supplied, the patent-food diet lasts some time.

The fat babies of the Geotrupes, the Copris and the Sacred Beetle finish at one brief sitting the dainty wherewith their narrow lodge is hung, a dainty frugally served and just sufficient to whet the appetite and prepare the stomach for coarser fare; but the Onthophagus’ grub, that puny dwarf, has enough to last it for a week and more. The spacious birth-chamber, which is out of all proportion to the nurseling’s size, has permitted this wastefulness.

At last the real loaf is attacked. In about a month everything is consumed, except the wall of the sack. And now the splendid part played by the hump stands revealed. Glass tubes, which I had got ready in anticipation, [282]allow me to watch the grub at work. Growing plumper and plumper and more and more humpbacked, it withdraws to one end of the cell, which has become a crumbling ruin. Here it builds a casket in which the transformation will take place. Its materials are the digestive residuum, converted into mortar and heaped up in the hump. The stercoral architect is about to construct a masterpiece of elegance out of its own ordure, held in reserve in that receptacle.

I follow its movements with the magnifying-glass. It curves itself into a loop, closes the circuit of the digestive apparatus, brings its two ends into contact and, with the tip of its mandibles, seizes a pellet of dung evacuated at that moment. This pellet is extracted very neatly and moulded into a brick which is measured most carefully. A slight bend of the creature’s neck sets the brick in place. Others follow, laid in the most scrupulously regular courses one above the other. Giving a tap here and there with its palpi, the grub makes sure of the steadiness of the parts, their accurate binding, their orderly arrangement. It turns round in the centre of the work as the edifice rises, even as a mason does when building a turret.

Sometimes the brick that has been laid becomes loose, because the cement has given way. The grub takes it up again with its mandibles, but, before replacing it, coats it with an adhesive moisture. It holds it to its anus, whence a gummy consolidating-extract trickles immediately and almost imperceptibly. The hump supplies the materials; the intestines give, if necessary, the glue that sticks them together.

In this way an attractive house is obtained, ovoid in form, polished as stucco within and adorned on the outside [283]with slightly projecting scales, similar to those on a cedar-cone. Each of these scales is one of the bricks that have been produced from the hump. The casket is not large: a cherry-stone would about represent its dimensions; but it is so accurate, so prettily fashioned that it will bear comparison with the finest products of entomological industry.

The Bull Onthophagus has not a monopoly of this jeweller’s art: all, throughout the group, excel in it to the same degree. One of the smallest, the Forked Onthophagus, whose work is hardly larger than a pepper-corn, is as expert as the others in the manufacture of boxes shaped like a cedar-cone. It is a family gift, an invariable gift, despite all differences in size, costume or hornery. The Bison Onitis, the Yellow-footed Oniticellus and certainly many others retire, for the transformation, into a residence similar in architecture to that of the Onthophagi; they too tell us that instincts are independent of structure.

In the first week of July let us complete the destruction of the Bull Onthophagus’ cell, already much impaired by the grub, which, after exhausting the contents of its knapsack, has gnawed the inner layer of the walls. The ruins are removed as easily as the husk of a ripe walnut. A sort of shelling process gives us the seed, that is to say, the nymphal casket, which comes out quite neatly, without sticking to its wrapper at any point. Break open the gem. The nymph is there, half-transparent and as it were carved out of crystal. Fortune favours me with a male, who is more interesting because of his frontal armour.

The horns outline a splendid crescent, leaning backwards and resting on the shoulders. They are swollen; [284]they are colourless, like everything that life elaborates in the midst of a generating-fluid; and at their base are the dark ocular specks, not yet capable of sight, but promising to become so. The clypeus is expanding and beginning to stand out. Seen from the front, the head is that of a Bull, with a wide muzzle and enormous horns, copied from those of the Aurochs.

If the artists in the time of the Pharaohs had known the immature Onthophagus, they would certainly have used him for their hieratical images. He is quite as good as the Sacred Beetle and even better from the point of view of those oddities which offer such scope to sacerdotal symbolism. On the front edge of the corselet, a single horn rises, as powerful as the two others and shaped like a cylinder ending in a conical knob. It points forward and is fixed in the middle of the frontal crescent, projecting a little beyond it. The arrangement is gloriously original. The carvers of hieroglyphics would have beheld in it the crescent of Isis wherein dips the edge of the world.

Some other peculiarities complete the nymph’s curious appearance. To right and left the abdomen is armed, on either side, with four little horns resembling crystal spikes. Total, eleven pieces in the creature’s harness: two on the forehead; one on the thorax; eight on the abdomen. The beast of yore delighted in queer horns: certain reptiles of the geological period stuck a pointed spur on their upper eyelids. The Onthophagus, more greatly daring, sports eight on the sides of his belly, in addition to the spear which he plants upon his back. The frontal horns may be excused: they are fairly common; but what does he propose to do with the others? Nothing at all. They are passing fancies, [285]jewels of early youth; the adult insect will not retain the least trace of them.

The nymph matures. The appendages of the fore-head, at first quite crystalline, now show, when held up to the light, a streak of reddish brown, curved like a bow. This is the real horn taking shape, consistency and colour. The appendage of the corselet and those of the belly, on the other hand, preserve their glassy appearance. They are barren sacks, void of any germ capable of development. The organism produced them in a moment of impulse; now, scornful, or perhaps powerless, it allows its work to wither and become useless.

When the nymph sheds its covering and the delicate tunic of the adult form is rent, these strange horns crumble into fragments, which fall away with the rest of the cast clothing. In the hope of finding at least a trace of the vanished things, the lens vainly explores the bases but lately occupied. There is nothing appreciable left: the nymph is now smooth; the real has given place to the non-existent. Of the accessory panoply so full of promise, absolutely naught remains: everything has vanished into thin air.

The Bull Onthophagus is not the only one endowed with these fleeting appendages, which completely disappear when the nymph sheds its clothes. The other members of the tribe possess similar horny manifestations on their bellies and corselets. One of them, the Spectral Onthophagus, on achieving the perfect state, adorns the front of his corselet with four tiny studs arranged in a semicircle. The two end ones stand alone; the two middle ones are together. These last correspond exactly with the base of the nymph’s thoracic horn and might easily be taken for the atrophied remnant of the [286]vanished appendage. We must abandon this idea, however, for the lateral studs, which are more developed than the middle ones, occupy points where the nymph had no horns. In this Onthophagus, as in the others, the nymphal armour is misleading and abortive.

Certain Dung-beetles related to the Onthophagi likewise possess horned nymphs. One of these is the Yellow-footed Oniticellus, the only one whom circumstances have allowed me to examine from this point of view. He wears, in the nymphal stage, a magnificent horn on his corselet and a row of four spikes on each side of his abdomen, as is the rule among the Onthophagi. This all disappears entirely in the adult insect.

It seems likely that, if I had known how to improve the occasion some years ago, when I was successfully rearing the Bison Onitis sent me from Montpellier, I should have perceived the same armour on the nymph’s thorax and abdomen. Not having been warned by earlier observations and being anxious also to disturb the pair of strangers as little as possible, I let the opportunity slip.

Let us remark lastly that the Onitis, Oniticellus and Onthophagus genera all three construct for the nymphosis a scaly cabin whose shape suggests the cedar-cone and the fruit of the alder. One may therefore admit, without being too venturesome, that the various builders of similar caskets are all acquainted with the nymphal panoply of a horn on the corselet and a diadem of eight spikes around the abdomen. This is not equivalent to saying that the armour determines the casket or the casket the armour. These curious details go together without influencing each other.

A simple setting forth of the facts is not enough: we should like to see the motive of this horned magnificence. [287]Is it a vague reminiscence of the customs of olden time, when life spent its excess of young sap upon quaint creations, banished to-day from our better-balanced world? Is the Onthophagus the dwarfed representative of an ancient race of horned animals now extinct? Does it give us a faint image of the past?

The surmise rests upon no valid foundation. The Dung-beetle is recent in the general chronology of created beings; he ranks among the last-comers. With him there is no means of going back to the mists of the past, which lends itself to the invention of imaginary precursors. Geological and even lacustrine schists, rich though the latter be in Diptera and Weevils, have hitherto furnished not the slightest relic of the dung-workers. This being so, it is wiser not to claim horned ancestors from the distant past as accounting for those degenerate descendants, the Onthophagi.

Since the past explains nothing, let us turn to the future. If the thoracic horn be not a reminiscence, it may be a promise. It represents a timid attempt, which the ages will harden into a permanent weapon. It lets us assist at the slow and gradual evolution of a new organ; it shows us life in travail of a thing not yet existing on the adult Beetle’s corselet, a thing which will exist one day. We catch the genesis of the species in the act; the present teaches us how the future is prepared.

And what does the Beetle propose to do with this object of his ambition, this spear which he hopes by and by to place upon his spine? At any rate as a dazzling piece of masculine finery the thing is already fashionable among the various foreign Scarabs that feed themselves and their grubs on decaying vegetable matter. [288]These giants among the wearers of armoured wing-cases delight in associating their placid corpulence with halberds terrible to gaze upon.

Look at one, Dynastes Hercules by name, a denizen of rotten tree-stumps under the scorching skies of the West Indies. The peaceable colossus well deserves his epithet: he measures three inches long. Of what service can the threatening rapier of the corselet and the toothed lifting-jack of the forehead be to him, unless it be to make him look grand in the presence of his female, herself deprived of these extravagances? Perhaps also they are of use to him in certain operations, even as the trident helps the Minotaurus to crumble his pellets and cart his rubbish. Implements of which we do not know the use always strike us as singular. Having never been intimate with the West-Indian Hercules, I must content myself with suspicions touching the purpose of his fearsome equipment.

Well, one of the subjects in my insect-house would achieve a similar savage finery if he persisted in his attempts. I speak of the Cow Onthophagus (O. vacca). His nymph has on its forehead a big horn, one only, bent backward; on its corselet it possesses a similar horn, jutting forward. The two, approaching their tips, look like some kind of pincers. What does the insect lack in order to acquire, on a smaller scale, the eccentric ornament of the West-Indian Scarab? It lacks perseverance. It matures the appendage of the forehead and allows that of the corselet to perish atrophied. It succeeds no better than the Bull Onthophagus in its attempt to grow a pointed stake upon its back; it loses a glorious opportunity of making itself fine for the wedding and terrible in battle.[289]

The others are no more successful. I bring up six different species. All, in the nymphal state, possess the thoracic horn and the eight-pointed ventral coronet; not one benefits by these advantages, which disappear altogether when the adult bursts its wrapping. My near neighbourhood numbers a dozen species of Onthophagi; the world contains some hundreds. All, natives and foreigners, have the same general structure; all most probably possess the dorsal appendage at an early age; and none of them, in spite of the variety of climate, torrid in one place, temperate in another, has succeeded in hardening it into a permanent horn.

Could not the future complete a work whose design is so very clearly traced? We are the more inclined to ask this, because appearances are all in favour of the question. Examine under the magnifying-glass the frontal horns of the Bull Onthophagus in the nymphal state; then with the same scrupulous care look at the spear upon the corselet. At first, there is no difference between them, except for the general configuration. In both cases we find the same glassy aspect, the same sheath swollen with colourless fluid, the same incipient organ plainly marked. A leg in process of formation is not more clearly announced than the horn on the corselet or those on the forehead.

Can time be lacking for the thoracic growth to become organized into a stiff and permanent appendage? The evolution of the nymph is swift; the insect is perfect in a few weeks. Could it not be that, though this brief space suffices to promote the maturity of the horns on the forehead, the thoracic horn requires a longer time to ripen? Let us prolong the nymphal period artificially [290]and give the germ time to develop. It seems to me that a decrease of temperature, moderated and maintained for some weeks, for months if necessary, should be capable of bringing about this result, by delaying the progress of the evolution. Then, with a gentle slowness, favourable to delicate formations, the promised organ will crystallize, so to speak, and become the spear promised by appearances.

The experiment attracted me. I was unable to undertake it for lack of the means whereby to produce a cold, even temperature over a long time. What should I have obtained if my penury had not made me abandon the enterprise? A retarding of the progress of the metamorphosis, but nothing more, apparently. The horn on the corselet would have persisted in its sterility and, sooner or later, would have disappeared.

I have reasons for my conviction. The abode of the Onthophagus engaged on his metamorphosis is not deep down; variations of temperature are easily felt. On the other hand, the seasons are capricious, especially the spring. Under the skies of Provence, the months of May and June, if the mistral lend a hand, have periods when the thermometer drops in such a way as to suggest a return of winter.

To these vicissitudes add the influence of a more northerly climate. The Onthophagi occupy a wide zone of latitude. Those of the north, less favoured by the sun than those of the south, might quite possibly have the date of their transformation postponed by a change in the weather and consequently be subjected to a lower temperature for several weeks. This would spin out the work of evolution and give the thoracic armour time to harden into horn, at rare intervals, as chance may prescribe. Here and there, then, the requisite condition [291]of a moderate or even low temperature at the time of the nymphosis actually exists, without the need of any artificial agency.

Well, what becomes of this surplus time placed at the service of the organic labour? Does the promised horn ripen? Not a bit of it: it withers just as it does under the stimulus of a hot sun. In the records of entomology I find no mention of an Onthophagus carrying a horn upon his corselet. No one would even have suspected the possibility of such an armour, if I had not bruited abroad the strange appearance of the nymph. The influence of climate, therefore, has nothing to do with the matter.

As we go more deeply into it, the question becomes more complicated. The horny appendages of the Onthophagus, the Copris, the Minotaurus and many others are the male’s prerogative; the female is without them or wears them only on a reduced and very modest scale. We must look upon these products as personal ornaments rather than as implements of labour. The male makes himself fine for the pairing; but, with the exception of the Minotaurus, who pins down the dry pellet that needs crushing and holds it in position with his trident, I know none that uses his armour as a tool. Horns and prongs on the forehead, crests and crescents on the corselet are the male coquette’s jewels and nothing more. The other sex requires no such baits to attract suitors: its femininity is enough; and finery is neglected.

Now here is something to give us food for thought. The nymph of the Onthophagus of the female sex, a nymph with an unarmed forehead, carries on its thorax a vitreous horn as long, as rich in promise as that of the other sex. If this latter excrescence be the design of an incipient ornament, then the former would be so too, [292]in which case the two sexes, both anxious for self-embellishment, would work with equal zeal to grow a horn upon their thorax. We should be witnessing the genesis of a species that would not be really an Onthophagus, but a derivative of the group; we should be beholding the commencement of singularities banished hitherto from among the Dung-beetles, none of whom, of either sex, has thought of planting a spear upon his chine. Stranger still: the female, always the more humbly attired throughout the entomological kingdom, would be vying with the male in her hankering after quaint adornment. An ambition of this sort leaves me incredulous.

We must therefore believe that, if the possibilities of the future should ever produce a Dung-beetle carrying a horn upon his corselet, this upsetter of present customs will not be an Onthophagus who has succeeded in maturing the thoracic appendage of the nymph, but rather an insect resulting from a new model. The creative power throws aside the old moulds and replaces them by others, fashioned with fresh care, in accordance with plans of an inexhaustible variety. Its laboratory is not a peddling rag-fair, where the living assume the cast clothes of the dead: it is a medallist’s studio, where each effigy receives the stamp of a special die. Its treasure-house of forms, illimitable in its riches, makes niggardliness impossible: there is no patching up of the old in order to create the new. It breaks every mould once used; it does away with it, without resorting to shabby after-touches.

Then what is the meaning of those horny preparations, which are always blighted before they come to anything? With no great shame I confess that I have not the slightest idea. My reply may not be couched in learned phraseology, but it has one merit, that of absolute sincerity.