More Hunting Wasps Part 4

By the aid of a vague phraseology which juggles with the secret of the centuries and the unknown things of life, it is easy to build up a theory in which our mental sloth delights, after being discouraged by difficult researches whose final result is doubt rather than positive statement. But if, so far from being satisfied with hazy generalities and adopting as current coin the terms consecrated by fas.h.i.+on, we have the perseverance to explore the truth as far as lies in our power, the aspect of things will undergo a great change and we shall discover that they are far less simple than our overprecipitate views declared them to be. Generalization is certainly a most valuable instrument: science indeed exists only by virtue of it. Let us none the less beware of generalizations which are not based upon very firm and manifold foundations.

When these foundations are lacking, the child is the great generalizer.

For him, the feathered world consists merely of birds; the race of reptiles merely of snakes, the only difference being that some are big and some are little. Knowing nothing, he generalizes in the highest degree; he simplifies, in his inability to perceive the complex. Later he will learn that the Sparrow is not the Bullfinch, that the Linnet is not the Greenfinch; he will particularize and to a greater degree each day, as his faculty of observation becomes more fully trained. In the beginning he saw nothing but resemblances; he now sees differences, but still not plainly enough to avoid incongruous comparisons.

In his adult years he will almost to a certainty commit zoological blunders similar to those which my gardener retails to me. Favier, an old soldier, has never opened a book, for the best of reasons. He barely knows how to cipher: arithmetic rather than reading is forced upon us by the brutalities of life. Having followed the flag over three-quarters of the globe, he has an open mind and a memory crammed with reminiscences, which does not prevent him, when we chat about animals, from making the most crazy a.s.sertions. For him the Bat is a Rat that has grown wings; the Cuckoo is a Sparrow-hawk retired from business; the Slug is a Snail who has lost his sh.e.l.l with the advance of years; the Nightjar (Known also as the Goatsucker, because of the mistaken belief that the bird sucks the milk of Goats, and, in America, as the Whippoorwill.--Translator's Note.), the Chaoucho-grapaou, as he calls her, is an elderly Toad, who, becoming enamoured of milk-food, has grown feathers, so that she may enter the byres and milk the Goats. It is impossible to drive these fantastic ideas out of his head. Favier himself, as will be seen, is an evolutionist after his own fas.h.i.+on, an evolutionist of a very daring type. In accounting for the origin of animals nothing gives him pause. He has a reply to everything: "this"

comes from "that." If you ask him why, he answers:

"Look at the resemblance!"

Shall we reproach him with these insanities, when we hear another, misled by the Monkey's build, acclaim the Pithecanthropus as man's precursor? Shall we reject the metamorphosis of the Chaoucho-grapaou, when people tell us in all seriousness that, in the present stage of scientific knowledge, it is absolutely proved that man is descended from some rough-hewn Ape? Of the two transformations, Favier's strikes me as the more credible. A painter of my acquaintance, a brother of the great composer Felicien David (Felicien Cesar David (1810-1876). His chief work was the choral symphony "Le Desert":--Translator's Note.), favoured me one day with his reflections on the human structure:

"Ve, moun bel ami," he said. "Ve, l'home a lou dintre d'un por et lou defero d'uno mounino." "See, my dear friend, see: man has the inside of a pig and the outside of a monkey."

I recommend the painter's aphorism to those who might like to discover man's origin in the Hog when the Ape has gone out of fas.h.i.+on. According to David, descent is proved by internal resemblances:

"L'home a lou dintre d'un por."

The inventory of precursory types sees nothing but organic resemblances and disdains the differences of apt.i.tude. By consulting only the bones, the vertebrae, the hair, the nervures of the wings, the joints of the antennae, the imagination may build up any sort of genealogical tree that will fit with our theories of cla.s.sification, for, when all is said, the animal, in its widest generalization, is represented by a digestive tube. With this common factor, the way lies open to every kind of error. A machine is judged not by this or that train of wheels, but by the nature of the work accomplished. The monumental roasting-jack of a waggoners' inn and a Breguet chronometer both have trains of cogwheels geared in almost a similar fas.h.i.+on. (Louis Breguet (1803-1883), a famous Parisian watchmaker and physicist.--Translator's Note.) Are we to cla.s.s the two mechanisms together? Shall we forget that the one turns a shoulder of mutton before the hearth, while the other divides time into seconds?

In the same way, the organic scaffolding is dominated from on high by the apt.i.tudes of the animal, especially that superior characteristic, the psychical apt.i.tudes. That the Chimpanzee and the hideous Gorilla possess close resemblances of structure to our own is obvious. But let us for a moment consider their apt.i.tudes. What differences, what a dividing gulf! Without exalting ourselves as high as the famous reed of which Pascal speaks, that reed which, in its weakness, by the mere fact that it knows itself to be crushed, is superior to the world that crushes it, we may at least ask to be shown, somewhere, an animal making an implement, which will multiply its skill and its strength, or taking possession of fire, the primordial element of progress. (Blaise Pascal(1623-1662). The allusion is to a pa.s.sage in the philosopher's "Pensees." Pascal describes man as a reed, the weakest thing in nature, but "a thinking reed."--Translator's Note.) Master of implements and of fire! These two apt.i.tudes, simple though they be, characterize man better than the number of his vertebrae and his molars.

You tell us that man, at first a hairy brute, walking on all fours, has risen on his hind-legs and shed his fur; and you complacently demonstrate how the elimination of the hairy pelt was effected. Instead of bolstering up a theory with a handful of fluff gained or lost, it would perhaps be better to settle how the original brute became the possessor of implements and fire. Apt.i.tudes are more important than hair; and you neglect them because it is there that the insurmountable difficulty really resides. See how the great master of evolution hesitates and stammers when he tries, by fair means or foul, to fit instinct into the mould of his formulae. It is not so easy to handle as the colour of the pelt, the length of the tail, the ear that droops or stands erect. Yes, our master well knows that this is where the shoe pinches! Instinct escapes him and brings his theory crumbling to the ground.

Let us return to what the Scoliae teach us on this question, which incidentally touches on our own origin. In conformity with the Darwinian ideas, we have accepted an unknown precursor, who by dint of repeated experiment, adopted as the victuals to be h.o.a.rded the larvae of the Scarabaeidae. This precursor, modified by varying circ.u.mstances, is supposed to have subdivided herself into ramifications, one of which, digging into vegetable mould and preferring the Cetonia to any other game inhabiting the same heap, became the Two-banded Scolia; another, also addicted to exploring the soil, but selecting the Oryctes, left as its descendant the Garden Scolia; and a third, establis.h.i.+ng itself in sandy ground, where it found the Anoxia, was the ancestress of the Interrupted Scolia. To these three ramifications we must beyond a doubt add others which complete the series of the Scolia. As their habits are known to me only by a.n.a.logy, I confine myself to mentioning them.

The three species at least, therefore, with which I am familiar would appear to be derived from a common precursor. To traverse the distance from the starting-point to the goal, all three have had to contend with difficulties, which are extremely grave if considered one by one and are aggravated even more by this circ.u.mstance, that the overcoming of one would lead to nothing unless the others were surmounted as successfully.

Success, then, is contingent upon a series of conditions, each one of which offers almost no chance of victory, so that the fulfilment of them all becomes a mathematical absurdity if we are to invoke accident alone.

And, in the first place, how was it that the Scolia of antiquity, having to provide rations for her carnivorous family, adopted for her prey only those larvae which, owing to the concentration of their nervous systems, form so remarkable and so rare an exception in the insect order? What chance would hazard offer her of obtaining this prey, the most suitable of all because the most vulnerable? The chance represented by unity compared with the indefinite number of entomological species. The odds are as one to immensity.

Let us continue. The larva of the Scarabaeid is snapped up underground, for the first time. The victim protests, defends itself after its fas.h.i.+on, coils itself up and presents to the sting on every side a surface on which a wound entails no serious danger. And yet the Wasp, an absolute novice, has to select, for the thrust of its poisoned weapon, one single point, narrowly restricted and hidden in the folds of the larva's body. If she miscalculates, she may be killed: the larva, irritated by the smarting puncture, is strong enough to disembowel her with the tusks of its mandibles. If she escapes the danger, she will nevertheless perish without leaving any offspring, since the necessary provisions will be lacking. Salvation for herself and her race depends on this: whether at the first thrust she is able to reach the little nervous plexus which measures barely one-fiftieth of an inch in width.

What chance has she of plunging her lancet into it, if there is nothing to guide her? The chance represented by unity compared with the number of points composing the victim's body. The odds are as one against immensity.

Let us proceed still further. The sting has reached the mark; the fat grub is deprived of movement. At what spots should the egg now be laid?

In front, behind, on the sides, the back or the belly? The choice is not a matter of indifference. The young grub will pierce the skin of its provender at the very spot on which the egg was fixed; and, once an opening is made, it will go ahead without hesitation. If this point of attack is ill-chosen, the nurseling runs the risk of presently finding under its mandibles some essential organ, which should have been respected until the end in order to keep the victuals fresh. Remember how difficult it is to complete the rearing when the tiny larva is moved from the place chosen by the mother. The game promptly becomes putrid and the Scolia dies.

It is impossible for me to state the precise motives which lead to the adoption of the spot on which the egg is laid; I can perceive general reasons, but the details escape me, as I am not well enough versed in the more delicate questions of anatomy and entomological physiology.

What I do know with absolute certainty is that the same spot is invariably chosen for laying the egg. With not a single exception, on all the victims extracted from the heap of garden mould--and they are numerous--the egg is fixed behind the ventral surface, on the verge of the brown patch formed by the contents of the digestive system.

If there be nothing to guide her, what chance has the mother of gluing her egg to this point, which is always the same because it is that most favourable to successful rearing? A very small point, represented by the ratio of two or three square millimetres (About 1/100 square inch.--Translator's Note.) to the entire surface of the victim's body.

Is this all? Not yet. The grub is hatched; it pierces the belly of the Cetonia-larva at the requisite point; it plunges its long neck into the entrails, ransacking them and filling itself to repletion. If it bite at random, if it have no other guide in the selection of t.i.t-bits than the preference of the moment and the violence of an imperious appet.i.te, it will infallibly incur the danger of being poisoned by putrid food, for the victim, if wounded in those organs which preserve a remnant of life in it, will die for good and all at the first mouthfuls.

The ample joint must be consumed with prudent skill: this part must be eaten before that and, after that, some other portion, always according to method, until the time approaches for the last bites. This marks the end of life for the Cetonia, but it also marks the end of the Scolia's feasting. If the grub be a novice in the art of eating, if no special instinct guide its mandibles in the belly of the prey, what chance has it of completing its perilous meal? As much as a starving Wolf would have of daintily dissecting his Sheep, when he tears at her gluttonously, rends her into shreds and gulps them down.

These four conditions of success, with chance so near to zero in each case, must all be realized together, or the grub will never be reared.

The Scolia may have captured a larva with close-packed nerve-centres, a Cetonia-grub, for instance; but this will go for nothing unless she direct her sting towards the only vulnerable point. She may know the whole secret of the art of stabbing her victim, but this means nothing if she does not know where to fasten her egg. The suitable spot may be found, but all the foregoing will be useless if the grub be not versed in the method to be followed in devouring its prey while keeping it alive. It is all or nothing.

Who would venture to calculate the final chance on which the future of the Scolia, or of her precursor, is based, that complex chance whose factors are four infinitely improbable occurrences, one might almost say four impossibilities? And such a conjunction is supposed to be a fortuitous result, to which the present instinct is due! Come, come!

From another point of view again, the Darwinian theory is at variance with the Scoliae and their prey. In the heap of garden mould which I exploited in order to write this record, three kinds of larvae dwell together, belonging to the Scarabaeid group: the Cetonia, the Oryctes and Scarabeus pentodon. Their internal structure is very nearly similar; their food is the same, consisting of decomposing vegetable matter; their habits are identical: they live underground in tunnels which are frequently renewed; they make a rough egg-shaped coc.o.o.n of earthy materials. Environment, diet, industry and internal structure are all similar; and yet one of these three larvae, the Cetonia's, reveals a most singular dissimilarity from its fellow-trenchermen: alone among the Scarabaeidae and, more than that, alone in all the immense order of insects, it walks upon its back.

If the differences were a matter of a few petty structural details, falling within the finical department of the cla.s.sifier, we might pa.s.s them over without hesitation; but a creature that turns itself upside down in order to walk with its belly in the air and never adopts any other method of locomotion, though it possesses legs and good legs at that, a.s.suredly deserves examination. How did the animal acquire its fantastic mode of progress and why does it think fit to walk in a fas.h.i.+on the exact contrary of that adopted by other beasts?

To these questions the science now in fas.h.i.+on always has a reply ready: adaptation to environment. The Cetonia-larva lives in crumbling galleries which it bores in the depths of the soil. Like the sweep who obtains a purchase with his back, loins and knees to hoist himself up the narrow pa.s.sage of a chimney, it gathers itself up, applies the tip of its belly to one wall of its gallery and its st.u.r.dy back to another; and the combined effort of these two levers results in moving it forward. The legs, which are used very little, indeed hardly at all, waste away and tend to disappear, as does any organ which is left unemployed; the back, on the other hand, the princ.i.p.al motive agent, grows stronger, is furrowed with powerful folds and bristles with grappling-hooks or hairs; and gradually, by adaptation to its environment, the creature loses the art of walking, which it does not practise, and replaces it by that of crawling on its back, a form of progress better suited to underground corridors.

So far so good. But now tell me, if you please, why the larvae of the Oryctes and the Scarabaeus, living in vegetable mould, the larva of the Anoxia, dwelling in the sand, and the larva of the c.o.c.kchafer in our cultivated fields have not also acquired the faculty of walking on their backs? In their galleries they follow the chimney-sweep's methods quite as cleverly as the Cetonia-grub; to move forward they make valiant use of their backs without yet having come to ambling with their bellies in the air. Can they have neglected to accommodate themselves to the demands of their environment? If evolution and environment cause the topsy-turvy progress of the one, I have the right, if words have any meaning whatever, to demand as much of the others, since their organization is so much alike and their mode of life identical.

I have but little respect for theories which, when confronted with two similar cases, are unable to interpret the one without contradicting the other. They make me laugh when they become merely childish. For example: why has the tiger a coat streaked black and yellow? A matter of environment, replies one of our evolutionary masters. Ambushed in bamboo thickets where the golden radiance of the sun is intersected by stripes of shadow cast by the foliage, the animal, the better to conceal itself, a.s.sumed the colour of its environment. The rays of the sun produced the tawny yellow of the coat; the stripes of shadow added the black bars.

And there you have it. Any one who refuses to accept the explanation must be very hard to please. I am one of these difficult persons. If it were a dinner-table jest, made over the walnuts and the wine, I would willingly sing ditto; but alas and alack, it is uttered without a smile, in a solemn and magisterial manner, as the last word in science!

Toussenel, in his day, asked the naturalists an insidious question.

(Alphonse Toussenel (1803-1885), the author of a number of learned and curious works on ornithology.--Translator's Note.) Why, he enquired, have Ducks a little curly feather on the rump? No one, so far as I know, had an answer for the teasing cross-examiner: evolution had not been invented then. In our time the reason why would be forthcoming in a moment, as lucid and as well-founded as the reason why of the tiger's coat.

Enough of childish nonsense. The Cetonia-grub walks on its back because it has always done so. The environment does not make the animal; it is the animal that is made for the environment. To this simple philosophy, which is quite antiquated nowadays, I will add another, which Socrates expressed in these words:

"What I know best is that I know nothing."

CHAPTER 6. THE TACHYTES.

The family of Wasps whose name I inscribe at the head of this chapter has not hitherto, so far as I know, made much noise in the world. Its annals are limited to methodical cla.s.sifications, which make very poor reading. The happy nations, men say, are those which have no history.

I accept this, but I also admit that it is possible to have a history without ceasing to be happy. In the conviction that I shall not disturb its prosperity, I will try to subst.i.tute the living, moving insect for the insect impaled in a cork-bottomed box.

It has been adorned with a learned name, derived from the Greek Tachytes, meaning rapidity, suddenness, speed. The creature's G.o.dfather, as we see, had a smattering of Greek; its denomination is none the less unfortunate: intended to instruct us by means of a characteristic feature, the name leads us astray. Why is speed mentioned in this connection? Why a label which prepares the mind for an exceptional velocity and announces a race of peerless coursers? Nimble diggers of burrows and eager hunters the Tachytes are, to be sure, but they are no better than a host of rivals. Not the Sphex, nor the Ammophila, nor the Bembex, nor many another would admit herself beaten in either flying or running. At the nesting-season, all this tiny world of huntresses is filled with astounding activity. The quality of a speedy worker being common to all, none can boast of it to the exclusion of the rest.

Had I had a vote when the Tachytes was christened, I should have suggested a short, harmonious, well-sounding name, meaning nothing else than the thing meant. What better, for example, than the term Sphex? The ear is satisfied and the mind is not corrupted by a prejudice, a source of error to the beginner. I have not nearly as much liking for Ammophila, which represents as a lover of the sands an animal whose establishments call for compact soil. In short, if I had been forced, at all costs, to concoct a barbarous appellation out of Latin or Greek in order to recall the creature's leading characteristic, I should have attempted to say, a pa.s.sionate lover of the Locust.

Love of the Locust, in the broader sense of the Orthopteron, an exclusive, intolerant love, handed down from mother to daughter with a fidelity which the centuries fail to impair, this, yes, this indeed depicts the Tachytes with greater accuracy than a name smacking of the race-course. The Englishman has his roast-beef; the German his sauerkraut; the Russian his caviare; the Neapolitan his macaroni; the Piedmontese his polenta; the man of Carpentras his tian. The Tachytes has her Locust. Her national dish is also that of the Sphex, with whom I boldly a.s.sociate her. The methodical cla.s.sifier, who works in cemeteries and seems to fly the living cities, keeps the two families far removed from each other because of considerations and attaching to the nervures of the wings and the joints of the palpi. At the risk of pa.s.sing for a heretic, I bring them together at the suggestion of the menu-card.

To my own knowledge, my part of the country possesses five species, one and all addicted to a diet of Orthoptera. Panzer's Tachytes (T. Panzeri, VAN DER LIND), girdled with red at the base of the abdomen, must be pretty rare. I surprise her from time to time working on the hard roadside banks and the trodden edges of the footpaths. There, to a depth of an inch at most, she digs her burrows, each isolated from the rest. Her prey is an adult, medium-sized Acridian (Locust or Gra.s.shopper.--Translator's Note.), such as the White-banded Sphex pursues. The captive of the one would not be despised by the other.

Gripped by the antennae, according to the ritual of the Sphex, the victim is trailed along on foot and laid beside the nest, with the head pointing towards the opening. The pit, prepared in advance, is closed for the time being with a tiny flagstone and some bits of gravel, in order to avoid either the invasion of a pa.s.ser-by or obstruction by landslips during the huntress' absence. A like precaution is taken by the White-banded Sphex. Both observe the same diet and the same customs.

The Tachytes clears the entrance to the home and goes in alone. She returns, puts out her head and, seizing her prey by the antennae, warehouses it by dragging backwards. I have repeated, at her expense, the tricks which I used to play on the Sphex. (For the author's experiments with the Languedocian, the Yellow-winged and the White-edged Sphex, cf. "The Hunting Wasps": chapter 11.--Translator's Note.) While the Tachytes is underground, I move the game away. The insect comes up again and sees nothing at its door; it comes out and goes to fetch its Locust, whom it places in position as before. This done, it goes in again by itself. In its absence I once more pull back the prey. Fresh emergence of the Wasp, who puts things to rights and persists in going down again, still by herself, however often I repeat the experiment.

Yet it would be very easy for her to put an end to my teasing: she would only have to descend straightway with her game, instead of leaving it for a moment on her doorstep. But, faithful to the usages of her race, she behaves as her ancestors behaved before her, even though the ancient custom happen to be unprofitable. Like the Yellow-winged Sphex, whom I have teased so often during her cellaring-operations, she is a narrow conservative, learning nothing and forgetting nothing.

Let us leave her to do her work in peace. The Locust disappears underground and the egg is laid upon the breast of the paralysed insect.

That is all: one carcase for each cell, no more. The entrance is stopped at last, first with stones, which will prevent the trickling of the embankment into the chamber; next with sweepings of dust, under which every vestige of the subterranean house disappears. It is now done: the Tachytes will come here no more. Other burrows will occupy her, distributed at the whim of her vagabond humour.

A cell provisioned before my eyes on the 22nd of August, in one of the walls in the harmas, contained the finished coc.o.o.n a week later. (The harmas was the piece of enclosed waste land in which the author used to study his insects in their natural state. Cf. "The Life of the Fly,"

by J. Henri Fabre, translated by Alexander Teixeira de Mattos: chapter 1.--Translator's Note.) I have not noted many examples of so rapid a development. This coc.o.o.n recalls, in its shape and texture, that of the Bembex-wasps. It is hard and mineralized, this is to say, the warp and woof of silk are hidden by a thick encrustation of sand. This composite structure seems to me characteristic of the family; at all events I find it in the three species whose coc.o.o.ns I know. If the Tachytes are nearly related to the Spheges in diet, they are far removed from them in the industry of their larvae. The first are workers in mosaic, encrusting a network of silk and sand; the second weave pure silk.

Of smaller size and clad in black with tr.i.m.m.i.n.gs of silvery down on the edge of the abdominal segments, the Tarsal Tachytes frequents the ledges of soft limestone in fairly populous colonies. (T. tarsina, LEP.) (According to M. J. Perez, to whom I submitted the Wasp of which I am about to speak, this Tachytes might well be a new species, if it is not Lepelletier's T. tarsina or its equivalent, Panzer's T. unicolor. Any one wis.h.i.+ng to clear up this point will always recognize the quarrelsome insect by its behaviour. A minute description seems useless to me in the type of investigation which I am pursuing.--Author's Note.) August and September are the season of her labours. Her burrows, very close to one another when an easily-worked vein presents itself, afford an ample harvest of coc.o.o.ns once the site is discovered. In a certain gravel-pit in the neighbourhood, with vertical walls visited by the sun, I have been able within a short s.p.a.ce of time to collect enough to fill the hollow of my hand completely. They differ from the coc.o.o.ns of the preceding species only in their smaller size. The provisions consist of young Acridians, varying from about a quarter to half an inch in length.

The adult insect does not appear in the a.s.sorted bags of game, being no doubt too tough for the feeble grub. All the carcases consist of Locust-larvae, whose budding wings leave the back uncovered and put one in mind of the short skirts of a skimpy jacket. Small so that it may be tender, the game is numerous so that it may suffice all needs. I count from two to four carcases to a cell. When the time comes we will discover the reason for these differences in the rations served.

The Mantis-killing Tachytes wears a red scarf, like her kinswoman, Panzer's Tachytes. (The Mantis-hunting Tachytes was submitted to examination by M. J. Perez, who failed to recognize her. This species may well be new to our fauna. I confine myself to calling her the Mantis-killing Tachytes and leave to the specialists the task of adorning her with a Latin name, if it be really the fact that the Wasp is not yet catalogued. I will be brief in my delineation. To my thinking the best description is this: mantis-hunter. With this information it is impossible to mistake the insect, in my district of course. I may add that it is black, with the first two abdominal segments, the legs and the tarsi a rusty red. Clad in the same livery and much smaller than the female, the male is remarkable for his eyes, which are of a beautiful lemon-yellow when he is alive. The length is nearly half an inch for the female and a little more than half this for the male.--Author's Note.) I do not think that she is very widely distributed. I made her acquaintance in the Serignan woods, where she inhabits, or rather used to inhabit--for I fear that I have depopulated and even destroyed the community by my repeated excavations--where she used to inhabit one of those little mounds of sand which the wind heaps up against the rosemary clumps. Outside this small community, I never saw her again. Her history, rich in incident, will be given with all the detail which it deserves. I will confine myself for the moment to mentioning her rations, which consist of Mantis-larvae, those of the Praying Mantis predominating. (Cf. "The Life of the Gra.s.shopper": chapters 6 to 9.--Translator's Note.) My lists record from three to sixteen heads for each cell. Once again we note a great inequality of rations, the reason for which we must try to discover.