My experiment with spike-lavender, naphthaline, and other odours seems to prove that odour proceeds from two sources. For emission substitute undulation, and the problem of the Great Peacock moth is explained. Without any material emanation a luminous point shakes the ether with its vibrations and fills with light a sphere of indefinite magnitude. So, or in some such manner, must the warning effluvium of the mother Oak Eggar operate. The moth does not emit molecules; but something about it vibrates, causing waves capable of propagation to distances incompatible with an actual diffusion of matter.

From this point of view, smell would have two domains—that of particles dissolved in the air and that of etheric waves.[7] The former domain alone is known to us. It is also known to the insect. It is this that warns the Saprinidae of the fetid arum, the Silphidae and the Necrophori of the putrid mole.

The second category of odour, far superior in its action through space, escapes us completely, because we lack the essential sensory equipment. The Great Peacock moth and the Oak Eggar know it at the time of their nuptial festivities. Many others must share it in differing degrees, according to the exigencies of their way of life.

Like light, odour has its X-rays. Let science, instructed by the insect, one day give us a radiograph sensitive to odours, and this artificial nose will open a new world of marvels.



CHAPTER XVII

THE ELEPHANT-BEETLE

Some of our machines have extraordinary-looking mechanisms, which remain inexplicable so long as they are seen in repose. But wait until the whole is in motion; then the uncouth-looking contrivance, with its cog-wheels interacting and its connecting-rods oscillating, will reveal the ingenious combination in which all things are skilfully disposed to produce the desired effects. It is the same with certain insects; with certain weevils, for instance, and notably with the Acorn-beetles or Balanini, which are adapted, as their name denotes, to the exploitation of acorns, nuts, and other similar fruits.

The most remarkable, in my part of France, is the Acorn Elephant (Balaninus elephas, Sch.). It is well named; the very name evokes a mental picture of the insect. It is a living caricature, this beetle with the prodigious snout. The latter is no thicker than a horsehair, reddish in colour, almost rectilinear, and of such length that in order not to stumble the insect is forced to carry it stiffly outstretched like a lance in rest. What is the use of this embarrassing pike, this ridiculous snout?

Here I can see some reader shrug his shoulders. Well, if the only end of life is to make money by hook or by crook, such questions are certainly ridiculous.

Happily there are some to whom nothing in the majestic riddle of the universe is little. They know of what humble materials the bread of thought is kneaded; a nutriment no less necessary than the bread made from wheat; and they know that both labourers and inquirers nourish the world with an accumulation of crumbs.

Let us take pity on the question, and proceed. Without seeing it at work, we already suspect that the fantastic beak of the Balaninus is a drill analogous to those which we ourselves use in order to perforate hard materials. Two diamond-points, the mandibles, form the terminal armature of the drill. Like the Larinidae, but under conditions of greater difficulty, the Curculionidae must use the implement in order to prepare the way for the installation of their eggs.

But however well founded our suspicion may be, it is not a certitude. I can only discover the secret by watching the insect at work.

Chance, the servant of those that patiently solicit it, grants me a sight of the acorn-beetle at work, in the earlier half of October. My surprise is great, for at this late season all industrial activity is as a rule at an end. The first touch of cold and the entomological season is over.

To-day, moreover, it is wild weather; the bise is moaning, glacial, cracking one's lips. One needs a robust faith to go out on such a day in order to inspect the thickets. Yet if the beetle with the long beak exploits the acorns, as I think it does, the time presses if I am to catch it at its work. The acorns, still green, have acquired their full growth. In two or three weeks they will attain the chestnut brown of perfect maturity, quickly followed by their fall.

My seemingly futile pilgrimage ends in success. On the evergreen oaks I surprise a Balaninus with the trunk half sunk in an acorn. Careful observation is impossible while the branches are shaken by the mistral. I detach the twig and lay it gently upon the ground. The insect takes no notice of its removal; it continues its work. I crouch beside it, sheltered from the storm behind a mass of underwood, and watch operations.

Shod with adhesive sandals which later on, in my laboratory, will allow it rapidly to climb a vertical sheet of glass, the elephant-beetle is solidly established on the smooth, steep curvature of the acorn. It is working its drill. Slowly and awkwardly it moves around its implanted weapon, describing a semicircle whose centre is the point of the drill, and then another semicircle in the reverse direction. This is repeated over and over again; the movement, in short, is identical with that we give to a bradawl when boring a hole in a plank.

Little by little the rostrum sinks into the acorn. At the end of an hour it has entirely disappeared. A short period of repose follows, and finally the instrument is withdrawn. What is going to happen next? Nothing on this occasion. The Balaninus abandons its work and solemnly retires, disappearing among the withered leaves. For the day there is nothing more to be learned.

But my interest is now awakened. On calm days, more favourable to the entomologist, I return to the woods, and I soon have sufficient insects to people my laboratory cages. Foreseeing a serious difficulty in the slowness with which the beetle labours, I prefer to study them indoors, with the unlimited leisure only to be found in one's own home.

The precaution is fortunate. If I had tried to continue as I began, and to observe the Balaninus in the liberty of the woods, I should never, even with the greatest good fortune, have had the patience to follow to the end the choice of the acorn, the boring of the hole, and the laying of the eggs, so meticulously deliberate is the insect in all its affairs; as the reader will soon be able to judge.

Three species of oak-tree compose the copse inhabited by the Balaninus: the evergreen oak and the pubescent oak, which would become fine trees if the woodman would give them time, and the kermes oak, a mere scrubby bush. The first species, which is the most abundant of the three, is that preferred by the Balaninus. The acorn is firm, elongated, and of moderate size; the cup is covered with little warts. The acorns of the pubescent oak are usually stunted, short, wrinkled, and fluted, and subject to premature fall. The aridity of the hills of Serignan is unfavourable to them. The Acorn-beetles accept them only in default of something better.

The kermes, a dwarf oak, a ridiculous tree which a man can jump over, surprises me by the wealth of its acorns, which are large, ovoidal growths, the cup being covered with scales. The Balaninus could not make a better choice; the acorn affords a safe, strong dwelling and a capacious storehouse of food.

A few twigs from these three trees, well provided with acorns, are arranged under the domes of some of my wire-gauze covers, the ends being plunged into a glass of water which will keep them fresh. A suitable number of couples are then introduced into the cages; and the latter are placed at the windows of my study, where they obtain the direct sunlight for the greater part of the day. Let us now arm ourselves with patience, and keep a constant watch upon events. We shall be rewarded; the exploitation of the acorn deserves to be seen.

Matters do not drag on for very long. Two days after these preparations I arrive at the precise moment when the task is commenced. The mother, larger than the male, and equipped with a longer drill, is inspecting her acorn, doubtless with a view to depositing her eggs.

She goes over it step by step, from the point to the stem, both above and below. On the warty cup progression is easy; over the rest of the surface it would be impossible, were not the soles of her feet shod with adhesive pads, which enable her to retain her hold in any position. Without the least uncertainty of footing, the insect walks with equal facility over the top or bottom or up the sides of the slippery fruit.

The choice is made; the acorn is recognised as being of good quality. The time has come to sink the hole. On account of its excessive length it is not easy to manoeuvre the beak. To obtain the best mechanical effect the instrument must be applied perpendicularly to the convex surface of the acorn, and the embarrassing implement which is carried in front of the insect when the latter is not at work must now be held in such a position as to be beneath the worker.

To obtain this result the insect rears herself upon her hind legs, supporting herself upon the tripod formed by the end of the wing-covers and the posterior tarsi. It would be hard to imagine anything more curious than this little carpenter, as she stands upright and brings her nasal bradawl down towards her body.

Now the drill is held plumb against the surface, and the boring commences. The method is that I witnessed in the wood on the day of the storm. Very slowly the insect veers round from right to left, then from left to right. Her drill is not a spiral gimlet which will sink itself by a constant rotary motion; it is a bradawl, or rather a trochar, which progresses by little bites, by alternative erosion, first in one direction, then the other.

Before continuing, let me record an accident which is too striking to be passed over. On various occasions I have found the insect dead in the midst of its task. The body is in an extraordinary position, which would be laughable if death were not always a serious thing, above all when it comes suddenly, in the midst of labour.

The drill is implanted in the acorn just a little beyond the tip; the work was only commenced. At the top of the drill, at right angles to it, the Balaninus is suspended in the air, far from the supporting surface of the acorn. It is dried, mummified, dead I know not how long. The legs are rigid and contracted under the body. Even if they retained the flexibility and the power of extension that were theirs in life, they would fall far short of the surface of the acorn. What then has happened, that this unhappy insect should be impaled like a specimen beetle with a pin through its head?

An accident of the workshop is responsible. On account of the length of its implement the beetle commences her work standing upright, supported by the two hind-legs. Imagine a slip, a false step on the part of the two adhesive feet; the unfortunate creature will immediately lose her footing, dragged by the elasticity of the snout, which she was forced to bend somewhat at the beginning. Torn away from her foothold, the suspended insect vainly struggles in air; nowhere can her feet, those safety anchors, find a hold. She starves at the end of her snout, for lack of foothold whereby to extricate herself. Like the artisans in our factories, the elephant-beetle is sometimes the victim of her tools. Let us wish her good luck, and sure feet, careful not to slip, and proceed.

On this occasion all goes well, but so slowly that the descent of the drill, even when amplified by the magnifying-glass, cannot be perceived. The insect veers round perpetually, rests, and resumes her work. An hour passes, two hours, wearying the observer by their sustained attention; for I wish to witness the precise moment when the beetle withdraws her drill, turns round, and deposits her egg in the mouth of the orifice. This, at least, is how I foresee the event.

Two hours go by, exhausting my patience. I call the household to my aid. Three of us take turns, keeping an uninterrupted watch upon the persevering creature whose secret I intend at any cost to discover.



It was well that I called in helpers to lend me their eyes and their attention. After eight hours—eight interminable hours, when it was nearly night, the sentinel on the watch calls me. The insect appears to have finished. She does, in fact, very cautiously withdraw her beak, as though fearing to slip. Once the tool is withdrawn she holds it pointing directly in front of her.

The moment has come.... Alas, no! Once more I am cheated; my eight hours of observation have been fruitless. The Balaninus decamps; abandons her acorn without laying her eggs. I was certainly right to distrust the result of observation in the open woods. Such concentration among the oaks, exposed to the sun, wind, and rain would have been an intolerable task.

During the whole of October, with the aid of such helpers as are needed, I remark a number of borings, not followed by the laying of eggs. The duration of the observer's task varies greatly. It usually amounts to a couple of hours; sometimes it exceeds half the day.

With what object are these perforations made, so laborious and yet so often unused? Let us first of all discover the position of the egg, and the first mouthfuls taken by the grub, and perhaps the reply will be found.

The peopled acorns remain on the oak, held in their cups as though nothing had occurred to the detriment of the cotyledons. With a little attention they may be readily recognised. Not far from the cup, on the smooth, still green envelope of the acorn a little point is visible; a tiny needle-prick. A narrow brown aureole, the product of mortification, is not long in appearing. This marks the opening of the hole. Sometimes, but more rarely, the hole is drilled through the cup itself.

Let us select those acorns which have been recently perforated: that is to say, those in which the perforation is not yet surrounded by the brown ring which appears in course of time. Let us shell them. Many contain nothing out of the way; the Balaninus has bored them but has not laid her eggs in them. They resemble the acorns which for hours and hours were drilled in my laboratory but not utilised. Many, on the contrary, contain an egg.

Now however distant the entrance of the bore may be, this egg is always at the bottom of the acorn, within the cup, at the base of the cotyledonary matter. The cup furnishes a thin film like swan-skin which imbibes the sapid exudations from the stem, the source of nourishment. I have seen a young grub, hatched under my eyes, eat as his first mouthfuls this tender cottony layer, which is moist and flavoured with tannin.

Such nutriment, juicy and easy of digestion, like all nascent organic matter, is only found in this particular spot; and it is only there, between the cup and the base of the cotyledons, that the elephant-beetle establishes her egg. The insect knows to a nicety the position of the portions best adapted to the feeble stomach of the newly hatched larva.

Above this is the tougher nutriment of the cotyledons. Refreshed by its first meal, the grub proceeds to attack this; not directly, but in the tunnel bored by the mother, which is littered with tiny crumbs and half-masticated shavings. With this light mealy diet the strength of the grub increases, and it then plunges directly into the substance of the acorn.

These data explain the tactics of the gravid mother. What is her object when, before proceeding to sink her hole, she inspects her acorn, from above, below, before and behind, with such meticulous care? She is making sure that the acorn is not already occupied. The larder is amply stored, but it does not contain enough for two. Never in fact, have I found two larvae in the same acorn. One only, always only one, digests the copious meal and converts it into a greenish dust before leaving it and descending to the ground. Only an insignificant shell remains uneaten. The rule is, to each grub one acorn.

Before trusting the egg to the acorn it is therefore essential to subject it to a thorough examination, to discover whether it already has an occupant. This possible occupant would be at the base of the acorn, under the cover of the cup. Nothing could be more secret than this hiding-place. Not an eye could divine the inhabitant if the surface of the acorn did not bear the mark of a tiny perforation.

This mark, just visible, is my guide. Its presence tells me that the acorn is inhabited, or at least that it has been prepared for the reception of the egg; its absence tells me that the acorn has not yet been appropriated. The elephant-beetle undoubtedly draws the same conclusions.

I see matters from on high, with a comprehensive glance, assisted at will by the magnifying-glass. I turn the acorn between my fingers for a moment, and the inspection is concluded. The beetle, investigating the acorn at close quarters, is often obliged to scrutinise practically the entire surface before detecting the tell-tale spot. Moreover, the welfare of her family demands a far more careful search than does my curiosity. This is the reason for her prolonged and deliberate examination.

The search is concluded; the acorn is recognised as unoccupied. The drill is applied to the surface and rotated for hours; then, very often, the insect departs, disdaining the result of her work. Why such protracted efforts? Was the beetle piercing the fruit merely to obtain drink and refreshment? Was the beak thrust into the depths of the base merely to obtain, from the choicer parts, a few sips of nutritious sap? Was the whole undertaking merely a matter of personal nourishment?

At first I believed this to be the solution, though surprised at the display of so much perseverance rewarded by the merest sip. The behaviour of the males, however, forced me to abandon this idea. They also possess the long beak, and could readily make such perforations if they wished; yet I have never seen one take up his stand upon an acorn and work at it with his augur. Then why this fruitless labour? A mere nothing suffices these abstemious creatures. A superficial operation performed upon the surface of a tender leaf yields them sufficient sustenance.

If the males, the unoccupied males who have leisure to enjoy the pleasures of the palate, ask no more than the sap of the leaf, how should the mothers, busied with the affairs of the breeding-season, find time to waste upon such dearly bought pleasures as the inner juices of the acorn? No, the acorn is not perforated for the purpose of drinking its juices. It is possible that once the beak is deeply sunk, the female may take a mouthful or two, but it is certain that food and drink are not the objects in view.

At last I begin to foresee the solution of the problem. The egg, as I have said, is always at the base of the acorn, in the midst of a soft cottony layer which is moistened by the sap which oozes from the stalk. The grub, upon hatching out, being as yet incapable of attacking the firm substance of the cotyledons, masticates the delicate felt-like layer at the base of the cup and is nourished by its juices.

But as the acorn matures this layer becomes more solid in its consistency. The soft tissues harden; the moist tissues dry up. There is a period during which the acorn fulfils to perfection the conditions most conducive to the welfare of the grub. At an earlier period matters would not have reached the desired stage; at a later period the acorn would be too mature.

The exterior of the acorn gives no indication whatever of the progress of this internal cookery. In order not to inflict unsuitable food on the grub, the mother beetle, not sufficiently informed by the look of the acorn, is thus obliged to taste, at the end of her trunk, the tissues at the base of the cup.

The nurse, before giving her charge a spoonful of broth, tests it by tasting it. In the same way the mother beetle plunges her trunk into the base of the cup, to test the contents before bestowing them upon her offspring. If the food is recognised as being satisfactory the egg is laid; if not, the perforation is abandoned without more ado. This explains the perforations which serve no purpose, in spite of so much labour; the tissues at the base of the cup, being carefully tested, are not found to be in the required condition. The elephant-beetles are difficult to please and take infinite pains when the first mouthful of the grub is in question. To place the egg in a position where the new-born grub will find light and juicy and easily digested nutriment is not enough for those far-seeing mothers; their cares look beyond this point. An intermediary period is desirable, which will lead the little larva from the delicacies of its first hours to the diet of hard acorn. This intermediary period is passed in the gallery, the work of the maternal beak. There it finds the crumbs, the shavings bitten off by the chisels of the rostrum. Moreover, the walls of the tunnel, which are softened by mortification, are better suited than the rest of the acorn to the tender mandibles of the larva.

Before setting to work on the cotyledons the grub does, in fact, commence upon the contents and walls of this tiny passage. It first consumes the shavings lying loose in the passage; it devours the brown fragments adhering to the walls; finally, being now sufficiently strengthened, it attacks the body of the acorn, plunges into it, and disappears. The stomach is ready; the rest is a blissful feast.

This intermediary tunnel must be of a certain length, in order to satisfy the needs of infancy, so the mother must labour at the work of drilling. If the perforation were made solely with the purpose of tasting the material at the base of the acorn and recognising its degree of maturity, the operation might be very much shorter, since the hole could be sunk through the cup itself from a point close to the base. This fact is not unrecognised; I have on occasion found the insect perforating the scaly cup.

In such a proceeding I see the attempt of a gravid mother pressed for time to obtain prompt information. If the acorn is suitable the boring will be recommenced at a more distant point, through the surface of the acorn itself. When an egg is to be laid the rule is to bore the hole from a point as distant as is practicable from the base—as far, in short, as the length of the rostrum will permit.

What is the object of this long perforation, which often occupies more than half the day? Why this tenacious perseverance when, not far from the stalk, at the cost of much less time and fatigue, the rostrum could attain the desired point—the living spring from which the new-born grub is to drink? The mother has her own reasons for toiling in this manner; in doing thus she still attains the necessary point, the base of the acorn, and at the same time—a most valuable result—she prepares for the grub a long tube of fine, easily digested meal.

But these are trivialities! Not so, if you please, but high and important matters, speaking to us of the infinite pains which preside over the preservation of the least of things; witnesses of a superior logic which regulates the smallest details.

The Balaninus, so happily inspired as a mother, has her place in the world and is worthy of notice. So, at least, thinks the blackbird, which gladly makes a meal of the insect with the long beak when fruits grow rare at the end of autumn. It makes a small mouthful, but a tasty, and is a pleasant change after such olives as yet withstand the cold.

And what without the blackbird and its rivalry of song were the reawakening of the woods in spring? Were man to disappear, annihilated by his own foolish errors, the festival of the life-bringing season would be no less worthily observed, celebrated by the fluting of the yellow-billed songster.

To the meritorious role of regaling the blackbird, the minstrel of the forest, the Balaninus adds another—that of moderating the superfluity of vegetation. Like all the mighty who are worthy of their strength, the oak is generous; it produces acorns by the bushel. What could the earth do with such prodigality? The forest would stifle itself for want of room; excess would ruin the necessary.

But no sooner is this abundance of food produced than there is an influx from every side of consumers only too eager to abate this inordinate production. The field-mouse, a native of the woods, stores acorns in a gravel-heap near its hay-lined nest. A stranger, the jay, comes in flocks from far away, warned I know not how. For some weeks it flies feasting from oak to oak, giving vent to its joys and its emotions in a voice like that of a strangling cat; then, its mission accomplished, it returns to the North whence it came.

The Balaninus has anticipated them all. The mother confided her eggs to the acorns while yet they were green. These have now fallen to earth, brown before their time, and pierced by a round hole through which the larva has escaped after devouring the contents. Under one single oak a basket might easily be filled with these ruined shells. More than the jay, more than the field-mouse, the elephant-beetle has contributed to reduce the superfluity of acorns.

Presently man arrives, busied in the interest of his pig. In my village it is quite an important event when the municipal hoardings announce the day for opening the municipal woods for the gathering of acorns. The more zealous visit the woods the day before and select the best places. Next day, at daybreak, the whole family is there. The father beats the upper branches with a pole; the mother, wearing a heavy hempen apron which enables her to force her way through the stubborn undergrowth, gathers those within reach of the hand, while the children collect those scattered upon the ground. First the small baskets are filled, then the big corbeilles, and then the sacks.

After the field-mouse, the jay, the weevil, and so many others have taken toll comes man, calculating how many pounds of bacon-fat his harvest will be worth. One regret mingles with the cheer of the occasion; it is to see so many acorns scattered on the ground which are pierced, spoiled, good for nothing. And man curses the author of this destruction; to hear him you would think the forest is meant for him alone, and that the oaks bear acorns only for the sake of his pig.

My friend, I would say to him, the forest guard cannot take legal proceedings against the offender, and it is just as well, for our egoism, which is inclined to see in the acorn only a garland of sausages, would have annoying results. The oak calls the whole world to enjoy its fruits. We take the larger part because we are the stronger. That is our only right.

More important than our rights is the equitable division of the fruits of the earth between the various consumers, great and little, all of whom play their part in this world. If it is good that the blackbird should flute and rejoice in the burgeoning of the spring, then it is no bad thing that acorns should be worm-eaten. In the acorn the dessert of the blackbird is prepared; the Balaninus, the tasty mouthful that puts flesh upon his flanks and music into his throat.

Let the blackbird sing, and let us return to the eggs of the Curculionidae. We know where the egg is—at the base of the acorn, because the tenderest and most juicy tissues of the fruit are there. But how did it get there, so far from the point of entry? A very trifling question, it is true; puerile even, if you will. Do not let us disdain to ask it; science is made of these puerilities.

The first man to rub a piece of amber on his sleeve and to find that it thereupon attracted fragments of chaff had certainly no vision of the electric marvels of our days. He was amusing himself in a childlike manner. Repeated, tested, and probed in every imaginable way, the child's experiment has become one of the forces of the world.

The observer must neglect nothing; for he never knows what may develop out of the humblest fact. So again we will ask: by what process did the egg of the elephant-beetle reach a point so far from the orifice in the acorn?

To one who was not already aware of the position of the egg, but knew that the grub attacked the base of the acorn first, the solution of that fact would be as follows: the egg is laid at the entrance of the tunnel, at the surface, and the grub, crawling down the gallery sunk by the mother, gains of its own accord this distant point where its infant diet is to be found.

Before I had sufficient data this was my own belief; but the mistake was soon exposed. I plucked an acorn just as the mother withdrew, after having for a moment applied the tip of the abdomen to the orifice of the passage just opened by her rostrum. The egg, so it seemed, must be there, at the entrance of the passage.... But no, it was not! It was at the other extremity of the passage! If I dared, I would say it had dropped like a stone into a well.

That idea we must abandon at once; the passage is extremely narrow and encumbered with shavings, so that such a thing would be impossible. Moreover, according to the direction of the stem, accordingly as it pointed upwards or downwards, the egg would have to fall downwards in one acorn and upwards in another.

A second explanation suggests itself, not less perilous. It might be said: "The cuckoo lays her egg on the grass, no matter where; she lifts it in her beak and places it in the nearest appropriate nest." Might not the Balaninus follow an analogous method? Does she employ the rostrum to place the egg in its position at the base of the acorn? I cannot see that the insect has any other implement capable of reaching this remote hiding-place.

Nevertheless, we must hastily reject such an absurd explanation as a last, desperate resort. The elephant-beetle certainly does not lay its egg in the open and seize it in its beak. If it did so the delicate ovum would certainly be destroyed, crushed in the attempt to thrust it down a narrow passage half choked with debris.

This is very perplexing. My embarrassment will be shared by all readers who are acquainted with the structure of the elephant-beetle. The grasshopper has a sabre, an oviscapt which plunges into the earth and sows the eggs at the desired depth; the Leuscopis has a probe which finds its way through the masonry of the mason-bee and lays the egg in the cocoon of the great somnolent larva; but the Balaninus has none of these swords, daggers, or pikes; she has nothing but the tip of her abdomen. Yet she has only to apply that abdominal extremity to the opening of the passage, and the egg is immediately lodged at the very bottom.

Anatomy will give us the answer to the riddle, which is otherwise indecipherable. I open the body of a gravid female. There, before my eyes, is something that takes my breath away. There, occupying the whole length of the body, is an extraordinary device; a red, horny, rigid rod; I had almost said a rostrum, so greatly does it resemble the implement which the insect carries on his head. It is a tube, fine as a horsehair, slightly enlarged at the free extremity, like an old-fashioned blunderbuss, and expanding to form an egg-shaped capsule at the point of origin.

This is the oviduct, and its dimensions are the same as those of the rostrum. As far as the perforating beak can plunge, so far the oviscapt, the interior rostrum, will reach. When working upon her acorn the female chooses the point of attack so that the two complementary instruments can each of them reach the desired point at the base of the acorn.

The matter now explains itself. The work of drilling completed, the gallery ready, the mother turns and places the tip of the abdomen against the orifice. She extrudes the internal mechanism, which easily passes through the loose debris of the boring. No sign of the probe appears, so quickly and discreetly does it work; nor is any trace of it to be seen when, the egg having been properly deposited, the implement ascends and returns to the abdomen. It is over, and the mother departs, and we have not caught a glimpse of her internal mechanism.

Was I not right to insist? An apparently insignificant fact has led to the authentic proof of a fact that the Larinidae had already made me suspect. The long-beaked weevils have an internal probe, an abdominal rostrum, which nothing in their external appearance betrays; they possess, among the hidden organs of the abdomen, the counterpart of the grasshopper's sabre and the ichneumon's dagger.



CHAPTER XVIII

THE PEA-WEEVIL—BRUCHUS PISI

Peas are held in high esteem by mankind. From remote ages man has endeavoured, by careful culture, to produce larger, tenderer, and sweeter varieties. Of an adaptable character, under careful treatment the plant has evolved in a docile fashion, and has ended by giving us what the ambition of the gardener desired. To-day we have gone far beyond the yield of the Varrons and Columelles, and further still beyond the original pea; from the wild seeds confided to the soil by the first man who thought to scratch up the surface of the earth, perhaps with the half-jaw of a cave-bear, whose powerful canine tooth would serve him as a ploughshare!

Where is it, this original pea, in the world of spontaneous vegetation? Our own country has nothing resembling it. Is it to be found elsewhere? On this point botany is silent, or replies only with vague probabilities.

We find the same ignorance elsewhere on the subject of the majority of our alimentary vegetables. Whence comes wheat, the blessed grain which gives us bread? No one knows. You will not find it here, except in the care of man; nor will you find it abroad. In the East, the birthplace of agriculture, no botanist has ever encountered the sacred ear growing of itself on unbroken soil.

Barley, oats, and rye, the turnip and the beet, the beetroot, the carrot, the pumpkin, and so many other vegetable products, leave us in the same perplexity; their point of departure is unknown to us, or at most suspected behind the impenetrable cloud of the centuries. Nature delivered them to us in the full vigour of the thing untamed, when their value as food was indifferent, as to-day she offers us the sloe, the bullace, the blackberry, the crab; she gave them to us in the state of imperfect sketches, for us to fill out and complete; it was for our skill and our labour patiently to induce the nourishing pulp which was the earliest form of capital, whose interest is always increasing in the primordial bank of the tiller of the soil.

As storehouses of food the cereal and the vegetable are, for the greater part, the work of man. The fundamental species, a poor resource in their original state, we borrowed as they were from the natural treasury of the vegetable world; the perfected race, rich in alimentary materials, is the result of our art.

If wheat, peas, and all the rest are indispensable to us, our care, by a just return, is absolutely necessary to them. Such as our needs have made them, incapable of resistance in the bitter struggle for survival, these vegetables, left to themselves without culture, would rapidly disappear, despite the numerical abundance of their seeds, as the foolish sheep would disappear were there no more sheep-folds.

They are our work, but not always our exclusive property. Wherever food is amassed, the consumers collect from the four corners of the sky; they invite themselves to the feast of abundance, and the richer the food the greater their numbers. Man, who alone is capable of inducing agrarian abundance, is by that very fact the giver of an immense banquet at which legions of feasters take their place. By creating more juicy and more generous fruits he calls to his enclosures, despite himself, thousands and thousands of hungry creatures, against whose appetites his prohibitions are helpless. The more he produces, the larger is the tribute demanded of him. Wholesale agriculture and vegetable abundance favour our rival the insect.

This is the immanent law. Nature, with an equal zeal, offers her mighty breast to all her nurslings alike; to those who live by the goods of others no less than to the producers. For us, who plough, sow, and reap, and weary ourselves with labour, she ripens the wheat; she ripens it also for the little Calender-beetle, which, although exempted from the labour of the fields, enters our granaries none the less, and there, with its pointed beak, nibbles our wheat, grain by grain, to the husk.

For us, who dig, weed, and water, bent with fatigue and burned by the sun, she swells the pods of the pea; she swells them also for the weevil, which does no gardener's work, yet takes its share of the harvest at its own hour, when the earth is joyful with the new life of spring.

Let us follow the manoeuvres of this insect which takes its tithe of the green pea. I, a benevolent ratepayer, will allow it to take its dues; it is precisely to benefit it that I have sown a few rows of the beloved plant in a corner of my garden. Without other invitation on my part than this modest expenditure of seed-peas it arrives punctually during the month of May. It has learned that this stony soil, rebellious to the culture of the kitchen-gardener, is bearing peas for the first time. In all haste therefore it has hurried, an agent of the entomological revenue system, to demand its dues.

Whence does it come? It is impossible to say precisely. It has come from some shelter, somewhere, in which it has passed the winter in a state of torpor. The plane-tree, which sheds its rind during the heats of the summer, furnishes an excellent refuge for homeless insects under its partly detached sheets of bark.

I have often found our weevil in such a winter refuge. Sheltered under the dead covering of the plane, or otherwise protected while the winter lasts, it awakens from its torpor at the first touch of a kindly sun. The almanack of the instincts has aroused it; it knows as well as the gardener when the pea-vines are in flower, and seeks its favourite plant, journeying thither from every side, running with quick, short steps, or nimbly flying.

A small head, a fine snout, a costume of ashen grey sprinkled with brown, flattened wing-covers, a dumpy, compact body, with two large black dots on the rear segment—such is the summary portrait of my visitor. The middle of May approaches, and with it the van of the invasion.

They settle on the flowers, which are not unlike white-winged butterflies. I see them at the base of the blossom or inside the cavity of the "keel" of the flower, but the majority explore the petals and take possession of them. The time for laying the eggs has not yet arrived. The morning is mild; the sun is warm without being oppressive. It is the moment of nuptial flights; the time of rejoicing in the splendour of the sunshine. Everywhere are creatures rejoicing to be alive. Couples come together, part, and re-form. When towards noon the heat becomes too great, the weevils retire into the shadow, taking refuge singly in the folds of the flowers whose secret corners they know so well. To-morrow will be another day of festival, and the next day also, until the pods, emerging from the shelter of the "keel" of the flower, are plainly visible, enlarging from day to day.

A few gravid females, more pressed for time than the others, confide their eggs to the growing pod, flat and meagre as it issues from its floral sheath. These hastily laid batches of eggs, expelled perhaps by the exigencies of an ovary incapable of further delay, seem to me in serious danger; for the seed in which the grub must establish itself is as yet no more than a tender speck of green, without firmness and without any farinaceous tissue. No larva could possible find sufficient nourishment there, unless it waited for the pea to mature.

But is the grub capable of fasting for any length of time when once hatched? It is doubtful. The little I have seen tells me that the new-born grub must establish itself in the midst of its food as quickly as possible, and that it perishes unless it can do so. I am therefore of opinion that such eggs as are deposited in immature pods are lost. However, the race will hardly suffer by such a loss, so fertile is the little beetle. We shall see directly how prodigal the female is of her eggs, the majority of which are destined to perish.

The important part of the maternal task is completed by the end of May, when the shells are swollen by the expanding peas, which have reached their final growth, or are but little short of it. I was anxious to see the female Bruchus at work in her quality of Curculionid, as our classification declares her.[8] The other weevils are Rhyncophora, beaked insects, armed with a drill with which to prepare the hole in which the egg is laid. The Bruchus possesses only a short snout or muzzle, excellently adapted for eating soft tissues, but valueless as a drill.

The method of installing the family is consequently absolutely different. There are no industrious preparations as with the Balinidae, the Larinidae, and the Rhynchitides. Not being equipped with a long oviscapt, the mother sows her eggs in the open, with no protection against the heat of the sun and the variations of temperature. Nothing could be simpler, and nothing more perilous to the eggs, in the absence of special characteristics which would enable them to resist the alternate trials of heat and cold, moisture and drought.

In the caressing sunlight of ten o'clock in the morning the mother runs up and down the chosen pod, first on one side, then on the other, with a jerky, capricious, unmethodical gait. She repeatedly extrudes a short oviduct, which oscillates right and left as though to graze the skin of the pod. An egg follows, which is abandoned as soon as laid.

A hasty touch of the oviduct, first here, then there, on the green skin of the pea-pod, and that is all. The egg is left there, unprotected, in the full sunlight. No choice of position is made such as might assist the grub when it seeks to penetrate its larder. Some eggs are laid on the swellings created by the peas beneath; others in the barren valleys which separate them. The first are close to the peas, the second at some distance from them. In short, the eggs of the Bruchus are laid at random, as though on the wing.

We observe a still more serious vice: the number of eggs is out of all proportion to the number of peas in the pod. Let us note at the outset that each grub requires one pea; it is the necessary ration, and is largely sufficient to one larva, but is not enough for several, nor even for two. One pea to each grub, neither more nor less, is the unchangeable rule.

We should expect to find signs of a procreative economy which would impel the female to take into account the number of peas contained in the pod which she has just explored; we might expect her to set a numerical limit on her eggs in conformity with that of the peas available. But no such limit is observed. The rule of one pea to one grub is always contradicted by the multiplicity of consumers.

My observations are unanimous on this point. The number of eggs deposited on one pod always exceeds the number of peas available, and often to a scandalous degree. However meagre the contents of the pod there is a superabundance of consumers. Dividing the sum of the eggs upon such or such a pod by that of the peas contained therein, I find there are five to eight claimants for each pea; I have found ten, and there is no reason why this prodigality should not go still further. Many are called, but few are chosen! What is to become of all these supernumeraries, perforce excluded from the banquet for want of space?

The eggs are of a fairly bright amber yellow, cylindrical in form, smooth, and rounded at the ends. Their length is at most a twenty-fifth of an inch. Each is affixed to the pod by means of a slight network of threads of coagulated albumen. Neither wind nor rain can loosen their hold.

The mother not infrequently emits them two at a time, one above the other; not infrequently, also, the uppermost of the two eggs hatches before the other, while the latter fades and perishes. What was lacking to this egg, that it should fail to produce a grub? Perhaps a bath of sunlight; the incubating heat of which the outer egg has robbed it. Whether on account of the fact that it is shadowed by the other egg, or for other reasons, the elder of the eggs in a group of two rarely follows the normal course, but perishes on the pod, dead without having lived.

There are exceptions to this premature end; sometimes the two eggs develop equally well; but such cases are exceptional, so that the Bruchid family would be reduced to about half its dimensions if the binary system were the rule. To the detriment of our peas and to the advantage of the beetle, the eggs are commonly laid one by one and in isolation.

A recent emergence is shown by a little sinuous ribbon-like mark, pale or whitish, where the skin of the pod is raised and withered, which starts from the egg and is the work of the new-born larva; a sub-epidermic tunnel along which the grub works its way, while seeking a point from which it can escape into a pea. This point once attained, the larva, which is scarcely a twenty-fifth of an inch in length, and is white with a black head, perforates the envelope and plunges into the capacious hollow of the pod.

It has reached the peas and crawls upon the nearest. I have observed it with the magnifier. Having explored the green globe, its new world, it begins to sink a well perpendicularly into the sphere. I have often seen it half-way in, wriggling its tail in the effort to work the quicker. In a short time the grub disappears and is at home. The point of entry, minute, but always easily recognisable by its brown coloration on the pale green background of the pea, has no fixed location; it may be at almost any point on the surface of the pea, but an exception is usually made of the lower half; that is, the hemisphere whose pole is formed by the supporting stem.

It is precisely in this portion that the germ is found, which will not be eaten by the larva, and will remain capable of developing into a plant, in spite of the large aperture made by the emergence of the adult insect. Why is this particular portion left untouched? What are the motives that safeguard the germ?

It goes without saying that the Bruchus is not considering the gardener. The pea is meant for it and for no one else. In refusing the few bites that would lead to the death of the seed, it has no intention of limiting its destruction. It abstains from other motives.

Let us remark that the peas touch laterally, and are pressed one against the other, so that the grub, when searching for a point of attack, cannot circulate at will. Let us also note that the lower pole expands into the umbilical excrescence, which is less easy of perforation than those parts protected by the skin alone. It is even possible that the umbilicum, whose organisation differs from that of the rest of the pea, contains a peculiar sap that is distasteful to the little grub.

Such, doubtless, is the reason why the peas exploited by the Bruchus are still able to germinate. They are damaged, but not dead, because the invasion was conducted from the free hemisphere, a portion less vulnerable and more easy of access. Moreover, as the pea in its entirety is too large for a single grub to consume, the consumption is limited to the portion preferred by the consumer, and this portion is not the essential portion of the pea.

With other conditions, with very much smaller or very much larger seeds, we shall observe very different results. If too small, the germ will perish, gnawed like the rest by the insufficiently provisioned inmate; if too large, the abundance of food will permit of several inmates. Exploited in the absence of the pea, the cultivated vetch and the broad bean afford us an excellent example; the smaller seed, of which all but the skin is devoured, is left incapable of germination; but the large bean, even though it may have held a number of grubs, is still capable of sprouting.

Knowing that the pod always exhibits a number of eggs greatly in excess of the enclosed peas, and that each pea is the exclusive property of one grub, we naturally ask what becomes of the superfluous grubs. Do they perish outside when the more precocious have one by one taken their places in their vegetable larder? or do they succumb to the intolerant teeth of the first occupants? Neither explanation is correct. Let us relate the facts.

On all old peas—they are at this stage dry—from which the adult Bruchus has emerged, leaving a large round hole of exit, the magnifying-glass will show a variable number of fine reddish punctuations, perforated in the centre. What are these spots, of which I count five, six, and even more on a single pea? It is impossible to be mistaken: they are the points of entry of as many grubs. Several grubs have entered the pea, but of the whole group only one has survived, fattened, and attained the adult age. And the others? We shall see.

At the end of May, and in June, the period of egg-laying, let us inspect the still green and tender peas. Nearly all the peas invaded show us the multiple perforations already observed on the dry peas abandoned by the weevils. Does this actually mean that there are several grubs in the pea? Yes. Skin the peas in question, separate the cotyledons, and break them up as may be necessary. We shall discover several grubs, extremely youthful, curled up comma-wise, fat and lively, each in a little round niche in the body of the pea.

Peace and welfare seem to reign in the little community. There is no quarrelling, no jealousy between neighbours. The feast has commenced; food is abundant, and the feasters are separated one from another by the walls of uneaten substance. With this isolation in separate cells no conflicts need be feared; no sudden bite of the mandibles, whether intentional or accidental. All the occupants enjoy the same rights of property, the same appetite, and the same strength. How does this communal feast terminate?

Having first opened them, I place a number of peas which are found to be well peopled in a glass test-tube. I open others daily. In this way I keep myself informed as to the progress of the various larvae. At first nothing noteworthy is to be seen. Isolated in its narrow chamber, each grub nibbles the substance around it, peacefully and parsimoniously. It is still very small; a mere speck of food is a feast; but the contents of one pea will not suffice the whole number to the end. Famine is ahead, and all but one must perish.

Soon, indeed, the aspect of things is entirely changed. One of the grubs—that which occupies the central position in the pea—begins to grow more quickly than the others. Scarcely has it surpassed the others in size when the latter cease to eat, and no longer attempt to burrow forwards. They lie motionless and resigned; they die that gentle death which comes to unconscious lives. Henceforth the entire pea belongs to the sole survivor. Now what has happened that these lives around the privileged one should be thus annihilated? In default of a satisfactory reply, I will propose a suggestion.

In the centre of the pea, less ripened than the rest of the seed by the chemistry of the sun, may there not be a softer pulp, of a quality better adapted to the infantile digestion of the grub? There, perhaps, being nourished by tenderer, sweeter, and perhaps more tasty tissues, the stomach becomes more vigorous, until it is fit to undertake less easily digested food. A nursling is fed on milk before proceeding to bread and broth. May not the central portion of the pea be the feeding-bottle of the Bruchid?

With equal rights, fired by an equal ambition, all the occupants of the pea bore their way towards the delicious morsel. The journey is laborious, and the grubs must rest frequently in their provisional niches. They rest; while resting they frugally gnaw the riper tissues surrounding them; they gnaw rather to open a way than to fill their stomachs.

Finally one of the excavators, favoured by the direction taken, attains the central portion. It establishes itself there, and all is over; the others have only to die. How are they warned that the place is taken? Do they hear their brother gnawing at the walls of his lodging? can they feel the vibration set up by his nibbling mandibles? Something of the kind must happen, for from that moment they make no attempt to burrow further. Without struggling against the fortunate winner, without seeking to dislodge him, those which are beaten in the race give themselves up to death. I admire this candid resignation on the part of the departed.

Another condition—that of space—is also present as a factor. The pea-weevil is the largest of our Bruchidae. When it attains the adult stage it requires a certain amplitude of lodging, which the other weevils do not require in the same degree. A pea provides it with a sufficiently spacious cell; nevertheless, the cohabitation of two in one pea would be impossible; there would be no room, even were the two to put up with a certain discomfort. Hence the necessity of an inevitable decimation, which will suppress all the competitors save one.

Now the superior volume of the broad bean, which is almost as much beloved by the weevil as the pea, can lodge a considerable community, and the solitary can live as a cenobite. Without encroaching on the domain of their neighbours, five or six or more can find room in the one bean.

Moreover, each grub can find its infant diet; that is, that layer which, remote from the surface, hardens only gradually and remains full of sap until a comparatively late period. This inner layer represents the crumb of a loaf, the rest of the bean being the crust.

In the pea, a sphere of much less capacity, it occupies the central portion; a limited point at which the grub develops, and lacking which it perishes; but in the bean it lines the wide adjoining faces of the two flattened cotyledons. No matter where the point of attack is made, the grub has only to bore straight down when it quickly reaches the softer tissues. What is the result? I have counted the eggs adhering to a bean-pod and the beans included in the pod, and comparing the two figures I find that there is plenty of room for the whole family at the rate of five or six dwellers in each bean. No superfluous larvae perish of hunger when barely issued from the egg; all have their share of the ample provision; all live and prosper. The abundance of food balances the prodigal fertility of the mother.

If the Bruchus were always to adopt the broad bean for the establishment of her family I could well understand the exuberant allowance of eggs to one pod; a rich food-stuff easily obtained evokes a large batch of eggs. But the case of the pea perplexes me. By what aberration does the mother abandon her children to starvation on this totally insufficient vegetable? Why so many grubs to each pea when one pea is sufficient only for one grub?

Matters are not so arranged in the general balance-sheet of life. A certain foresight seems to rule over the ovary so that the number of mouths is in proportion to the abundance or scarcity of the food consumed. The Scarabaeus, the Sphex, the Necrophorus, and other insects which prepare and preserve alimentary provision for their families, are all of a narrowly limited fertility, because the balls of dung, the dead or paralysed insects, or the buried corpses of animals on which their offspring are nourished are provided only at the cost of laborious efforts.

The ordinary bluebottle, on the contrary, which lays her eggs upon butcher's meat or carrion, lays them in enormous batches. Trusting in the inexhaustible riches represented by the corpse, she is prodigal of offspring, and takes no account of numbers. In other cases the provision is acquired by audacious brigandage, which exposes the newly born offspring to a thousand mortal accidents. In such cases the mother balances the chances of destruction by an exaggerated flux of eggs. Such is the case with the Meloides, which, stealing the goods of others under conditions of the greatest peril, are accordingly endowed with a prodigious fertility.

The Bruchus knows neither the fatigues of the laborious, obliged to limit the size of her family, nor the misfortunes of the parasite, obliged to produce an exaggerated number of offspring. Without painful search, entirely at her ease, merely moving in the sunshine over her favourite plant, she can ensure a sufficient provision for each of her offspring; she can do so, yet is foolish enough to over-populate the pod of the pea; a nursery insufficiently provided, in which the great majority will perish of starvation. This ineptitude is a thing I cannot understand: it clashes too completely with the habitual foresight of the maternal instinct.

I am inclined to believe that the pea is not the original food plant of the Bruchus. The original plant must rather have been the bean, one seed of which is capable of supporting half a dozen or more larvae. With the larger cotyledon the crying disproportion between the number of eggs and the available provision disappears.

Moreover, it is indubitable that the bean is of earlier date than the pea. Its exceptional size and its agreeable flavour would certainly have attracted the attention of man from the remotest periods. The bean is a ready-made mouthful, and would be of the greatest value to the hungry tribe. Primitive man would at an early date have sown it beside his wattled hut. Coming from Central Asia by long stages, their wagons drawn by shaggy oxen and rolling on the circular discs cut from the trunks of trees, the early immigrants would have brought to our virgin land, first the bean, then the pea, and finally the cereal, that best of safeguards against famine. They taught us the care of herds, and the use of bronze, the material of the first metal implement. Thus the dawn of civilisation arose over France. With the bean did those ancient teachers also involuntarily bring us the insect which to-day disputes it with us? It is doubtful; the Bruchidae seem to be indigenous. At all events, I find them levying tribute from various indigenous plants, wild vegetables which have never tempted the appetite of man. They abound in particular upon the great forest vetch (Lathyrus latifolius), with its magnificent heads of flowers and long handsome pods. The seeds are not large, being indeed smaller than the garden pea; but eaten to the very skin, as they invariably are, each is sufficient to the needs of its grub.

We must not fail to note their number. I have counted more than twenty in a single pod, a number unknown in the case of the pea, even in the most prolific varieties. Consequently this superb vetch is in general able to nourish without much loss the family confided to its pod.

Where the forest vetch is lacking, the Bruchus, none the less, bestows its habitual prodigality of eggs upon another vegetable of similar flavour, but incapable of nourishing all the grubs: for the example, the travelling vetch (Vicia peregrina) or the cultivated vetch (Vicia sativa). The number of eggs remains high even upon insufficient pods, because the original food-plant offered a copious provision, both in the multiplicity and the size of the seeds. If the Bruchus is really a stranger, let us regard the bean as the original food-plant; if indigenous, the large vetch.

Sometime in the remote past we received the pea, growing it at first in the prehistoric vegetable garden which already supplied the bean. It was found a better article of diet than the broad bean, which to-day, after such good service, is comparatively neglected. The weevil was of the same opinion as man, and without entirely forgetting the bean and the vetch it established the greater part of its tribe upon the pea, which from century to century was more widely cultivated. To-day we have to share our peas: the Bruchidae take what they need, and bestow their leavings on us.

This prosperity of the insect which is the offspring of the abundance and quality of our garden products is from another point of view equivalent to decadence. For the weevil, as for ourselves, progress in matters of food and drink is not always beneficial. The race would profit better if it remained frugal. On the bean and the vetch the Bruchus founded colonies in which the infant mortality was low. There was room for all. On the pea-vine, delicious though its fruits may be, the greater part of its offspring die of starvation. The rations are few, and the hungry mouths are multitudinous.

We will linger over this problem no longer. Let us observe the grub which has now become the sole tenant of the pea by the death of its brothers. It has had no part in their death; chance has favoured it, that is all. In the centre of the pea, a wealthy solitude, it performs the duty of a grub; the sole duty of eating. It nibbles the walls enclosing it, enlarging its lodgment, which is always entirely filled by its corpulent body. It is well shaped, fat, and shining with health. If I disturb it, it turns gently in its niche and sways its head. This is its manner of complaining of my importunities. Let us leave it in peace.

It profits so greatly and so swiftly by its position that by the time the dog-days have come it is already preparing for its approaching liberation. The adult is not sufficiently well equipped to open for itself a way out through the pea, which is now completely hardened. The larva knows of this future helplessness, and with consummate art provides for its release. With its powerful mandibles it bores a channel of exit, exactly round, with extremely clean-cut sides. The most skilful ivory-carver could do no better.

To prepare the door of exit in advance is not enough; the grub must also provide for the tranquillity essential to the delicate processes of nymphosis. An intruder might enter by the open door and injure the helpless nymph. This passage must therefore remain closed. But how?

As the grub bores the passage of exit it consumes the farinaceous matter without leaving a crumb. Having come to the skin of the pea it stops short. This membrane, semi-translucid, is the door to the chamber of metamorphosis, its protection against the evil intentions of external creatures.

It is also the only obstacle which the adult will encounter at the moment of exit. To lessen the difficulty of opening it the grub takes the precaution of gnawing at the inner side of the skin, all round the circumference, so as to make a line of least resistance. The perfect insect will only have to heave with its shoulder and strike a few blows with its head in order to raise the circular door and knock it off like the lid of a box. The passage of exit shows through the diaphanous skin of the pea as a large circular spot, which is darkened by the obscurity of the interior. What passes behind it is invisible, hidden as it is behind a sort of ground glass window.

A pretty invention, this little closed porthole, this barricade against the invader, this trap-door raised by a push when the time has come for the hermit to enter the world. Shall we credit it to the Bruchus? Did the ingenious insect conceive the undertaking? Did it think out a plan and work out a scheme of its own devising? This would be no small triumph for the brain of a weevil. Before coming to a conclusion let us try an experiment.

I deprive certain occupied peas of their skin, and I dry them with abnormal rapidity, placing them in glass test-tubes. The grubs prosper as well as in the intact peas. At the proper time the preparations for emergence are made.

If the grub acts on its own inspiration, if it ceases to prolong its boring directly it recognises that the outer coating, auscultated from time to time, is sufficiently thin, what will it do under the conditions of the present test? Feeling itself at the requisite distance from the surface it will stop boring; it will respect the outer layer of the bare pea, and will thus obtain the indispensable protecting screen.

Nothing of the kind occurs. In every case the passage is completely excavated; the entrance gapes wide open, as large and as carefully executed as though the skin of the pea were in its place. Reasons of security have failed to modify the usual method of work. This open lodging has no defence against the enemy; but the grub exhibits no anxiety on this score.

Neither is it thinking of the outer enemy when it bores down to the skin when the pea is intact, and then stops short. It suddenly stops because the innutritious skin is not to its taste. We ourselves remove the parchment-like skins from a mess of pease-pudding, as from a culinary point of view they are so much waste matter. The larva of the Bruchus, like ourselves, dislikes the skin of the pea. It stops short at the horny covering, simply because it is checked by an uneatable substance. From this aversion a little miracle arises; but the insect has no sense of logic; it is passively obedient to the superior logic of facts. It obeys its instinct, as unconscious of its act as is a crystal when it assembles, in exquisite order, its battalions of atoms.

Sooner or later during the month of August we see a shadowy circle form on each inhabited pea; but only one on each seed. These circles of shadow mark the doors of exit. Most of them open in September. The lid, as though cut out with a punch, detaches itself cleanly and falls to the ground, leaving the orifice free. The Bruchus emerges, freshly clad, in its final form.

The weather is delightful. Flowers are abundant, awakened by the summer showers; and the weevils visit them in the lovely autumn weather. Then, when the cold sets in, they take up their winter quarters in any suitable retreat. Others, still numerous, are less hasty in quitting the native seed. They remain within during the whole winter, sheltered behind the trap-door, which they take care not to touch. The door of the cell will not open on its hinges, or, to be exact, will not yield along the line of least resistance, until the warm days return. Then the late arrivals will leave their shelter and rejoin the more impatient, and both will be ready for work when the pea-vines are in flower.

To take a general view of the instincts in their inexhaustible variety is, for the observer, the great attraction of the entomological world; for nowhere do we gain a clearer sight of the wonderful way in which the processes of life are ordered. Thus regarded entomology is not, I know, to the taste of everybody; the simple creature absorbed in the doings and habits of insects is held in low esteem. To the terrible utilitarian, a bushel of peas preserved from the weevil is of more importance than a volume of observations which bring no immediate profit.

Yet who has told you, O man of little faith, that what is useless to-day will not be useful to-morrow? If we learn the customs of insects or animals we shall understand better how to protect our goods. Do not despise disinterested knowledge, or you may rue the day. It is by the accumulation of ideas, whether immediately applicable or otherwise, that humanity has done, and will continue to do, better to-day than yesterday, and better to-morrow than to-day. If we live on peas and beans, which we dispute with the weevil, we also live by knowledge, that mighty kneading-trough in which the bread of progress is mixed and leavened. Knowledge is well worth a few beans.

Among other things, knowledge tells us: "The seedsman need not go to the expense of waging war upon the weevil. When the peas arrive in the granary, the harm is already done; it is irreparable, but not transmissible. The untouched peas have nothing to fear from the neighbourhood of those which have been attacked, however long the mixture is left. From the latter the weevils will issue when their time has come; they will fly away from the storehouse if escape is possible; if not, they will perish without in any way attacking the sound peas. No eggs, no new generation will ever be seen upon or within the dried peas in the storehouse; there the adult weevil can work no further mischief."

The Bruchus is not a sedentary inhabitant of granaries: it requires the open air, the sun, the liberty of the fields. Frugal in everything, it absolutely disdains the hard tissues of the vegetable; its tiny mouth is content with a few honeyed mouthfuls, enjoyed upon the flowers. The larvae, on the other hand, require the tender tissues of the green pea growing in the pod. For these reasons the granary knows no final multiplication on the part of the despoiler.

The origin of the evil is in the kitchen-garden. It is there that we ought to keep a watch on the misdeeds of the Bruchus, were it not for the fact that we are nearly always weaponless when it comes to fighting an insect. Indestructible by reason of its numbers, its small size, and its cunning, the little creature laughs at the anger of man. The gardener curses it, but the weevil is not disturbed: it imperturbably continues its trade of levying tribute. Happily we have assistants more patient and more clear-sighted than ourselves.

During the first week of August, when the mature Bruchus begins to emerge, I notice a little Chalcidian, the protector of our peas. In my rearing-cages it issues under my eyes in abundance from the peas infested by the grub of the weevil. The female has a reddish head and thorax; the abdomen is black, with a long augur-like oviscapt. The male, a little smaller, is black. Both sexes have reddish claws and thread-like antennae.

In order to escape from the pea the slayer of the weevil makes an opening in the centre of the circular trap-door which the grub of the weevil prepared in view of its future deliverance. The slain has prepared the way for the slayer. After this detail the rest may be divined.

When the preliminaries to the metamorphosis are completed, when the passage of escape is bored and furnished with its lid of superficial membrane, the female Chalcidian arrives in a busy mood. She inspects the peas, still on the vine, and enclosed in their pods; she auscultates them with her antennae; she discovers, hidden under the general envelope, the weak points in the epidermic covering of the peas. Then, applying her oviscapt, she thrusts it through the side of the pod and perforates the circular trap-door. However far withdrawn into the centre of the pea, the Bruchus, whether larvae or nymph, is reached by the long oviduct. It receives an egg in its tender flesh, and the thing is done. Without possibility of defence, since it is by now a somnolent grub or a helpless pupa, the embryo weevil is eaten until nothing but skin remains. What a pity that we cannot at will assist the multiplication of this eager exterminator! Alas! our assistants have got us in a vicious circle, for if we wished to obtain the help of any great number of Chalcidians we should be obliged in the first place to breed a multiplicity of Bruchidae.



CHAPTER XIX

AN INVADER.—THE HARICOT-WEEVIL

If there is one vegetable on earth that more than any other is a gift of the gods, it is the haricot bean. It has all the virtues: it forms a soft paste upon the tongue; it is extremely palatable, abundant, inexpensive, and highly nutritious. It is a vegetable meat which, without being bloody and repulsive, is the equivalent of the horrors outspread upon the butcher's slab. To recall its services the more emphatically, the Provencal idiom calls it the gounflo-gus—the filler of the poor.

Blessed Bean, consoler of the wretched, right well indeed do you fill the labourer, the honest, skilful worker who has drawn a low number in the crazy lottery of life. Kindly Haricot, with three drops of oil and a dash of vinegar you were the favourite dish of my young years; and even now, in the evening of my days, you are welcome to my humble porringer. We shall be friends to the last.

To-day it is not my intention to sing your merits; I wish simply to ask you a question, being curious: What is the country of your origin? Did you come from Central Asia with the broad bean and the pea? Did you make part of that collection of seeds which the first pioneers of culture brought us from their gardens? Were you known to antiquity?

Here the insect, an impartial and well-informed witness, answers: "No; in our country antiquity was not acquainted with the haricot. The precious vegetable came hither by the same road as the broad bean. It is a foreigner, and of comparatively recent introduction into Europe."

The reply of the insect merits serious examination, supported as it is by extremely plausible arguments. Here are the facts. For years attentive to matters agricultural, I had never seen haricots attacked by any insect whatever; not even by the Bruchidae, the licensed robbers of leguminous seeds.

On this point I have questioned my peasant neighbours. They are men of the extremest vigilance in all that concerns their crops. To steal their property is an abominable crime, swiftly discovered. Moreover, the housewife, who individually examines all beans intended for the saucepan, would inevitably find the malefactor.

All those I have spoken to replied to my questions with a smile in which I read their lack of faith in my knowledge of insects. "Sir," they said, "you must know that there are never grubs in the haricot bean. It is a blessed vegetable, respected by the weevil. The pea, the broad bean, the vetch, and the chick-pea all have their vermin; but the haricot, lou gounflo-gus, never. What should we do, poor folk as we are, if the Courcoussoun robbed us of it?"

The fact is that the weevil despises the haricot; a very curious dislike if we consider how industriously the other vegetables of the same family are attacked. All, even the beggarly lentil, are eagerly exploited; whilst the haricot, so tempting both as to size and flavour, remains untouched. It is incomprehensible. Why should the Bruchus, which without hesitation passes from the excellent to the indifferent, and from the indifferent to the excellent, disdain this particularly toothsome seed? It leaves the forest vetch for the pea, and the pea for the broad bean, as pleased with the small as with the large, yet the temptations of the haricot bean leave it indifferent. Why?

Apparently because the haricot is unknown to it. The other leguminous plants, whether native or of Oriental origin, have been familiar to it for centuries; it has tested their virtues year by year, and, confiding in the lessons of the past, it bases its forethought for the future upon ancient custom. The haricot is avoided as a newcomer, whose merits it has not yet learned.

The insect emphatically informs us that with us the haricot is of recent date. It has come to us from a distant country: and assuredly from the New World. Every edible vegetable attracts its consumers. If it had originated in the Old World the haricot would have had its licensed consumers, as have the pea, the lentil, and the broad bean. The smallest leguminous seed, if barely bigger than a pin's head, nourishes its weevil; a dwarf which patiently nibbles it and excavates a dwelling; but the plump, delicious haricot is spared.

This astonishing immunity can have only one explanation: like the potato and the maize-plant, the haricot is a gift of the New World. It arrived in Europe without the company of the insect which exploits it in its native country; it has found in our fields another world of insects, which have despised it because they did not know it. Similarly the potato and the ear of maize are untouched in France unless their American consumers are accidentally imported with them.

The verdict of the insect is confirmed by the negative testimony of the ancient classics; the haricot never appears on the table of the Greek or Roman peasant. In the second Eclogue of Virgil Thestylis prepares the repast of the harvesters:—

Thestylis et rapido fessis messoribus aestu Allia serpyllumque herbas contundit olentes.

This mixture is the equivalent of the aioli, dear to the Provencal palate. It sounds very well in verse, but is not very substantial. On such an occasion men would look for that fundamental dish, the plate of red haricots, seasoned with chopped onions. All in good time; this at least would ballast the stomach. Thus refreshed in the open air, listening to the song of the cigales, the gang of harvesters would take their mid-day rest and gently digest their meal in the shadows of the sheaves. Our modern Thestylis, differing little from her classic sister, would take good care not to forget the gounflo-gus, that economical resource of large appetites. The Thestylis of the past did not think of providing it because she did not know it.

The same author shows us Tityrus offering a night's hospitality to his friend Meliboeus, who has been driven from his property by the soldiers of Octavius, and goes limping behind his flock of goats. We shall have, says Tityrus, chestnuts, cheese, and fruits. History does not say if Meliboeus allowed himself to be tempted. It is a pity; for during the frugal meal we might have learned in a more explicit fashion that the shepherds of the ancient world were not acquainted with the haricot.

Ovid tells us, in a delightful passage, of the manner in which Philemon and Baucis received the gods unawares as guests in their humble cottage. On the three-legged table, which was levelled by means of a potsherd under one of the legs, they served cabbage soup, rusty bacon, eggs poached for a minute in the hot cinders, cornel-berries pickled in brine, honey, and fruits. In this rustic abundance one dish was lacking; an essential dish, which the Baucis of our countryside would never forget. After bacon soup would follow the obligatory plate of haricots. Why did Ovid, so prodigal of detail, neglect to mention a dish so appropriate to the occasion? The reply is the same as before: because he did not know of it.

In vain have I recapitulated all that my reading has taught me concerning the rustic dietary of ancient times; I can recollect no mention of the haricot. The worker in the vineyard and the harvester have their lupins, broad beans, peas, and lentils, but never the bean of beans, the haricot.

The haricot has a reputation of another kind. It is a source of flatulence; you eat it, as the saying is, and then you take a walk. It lends itself to the gross pleasantries loved of the populace; especially when they are formulated by the shameless genius of an Aristophanes or a Plautus. What merriment over a simple allusion to the sonorous bean, what guffaws from the throats of Athenian sailors or Roman porters! Did the two masters, in the unfettered gaiety of a language less reserved than our own, ever mention the virtues of the haricot? No; they are absolutely silent concerning the trumpet-voiced vegetable.

The name of the bean is a matter for reflection. It is of an unfamiliar sound, having no affinity with our language. By its unlikeness to our native combinations of sounds, it makes one think of the West Indies or South America, as do caoutchouc and cacao. Does the word as a matter of fact come from the American Indians? Did we receive, together with the vegetable, the name by which it is known in its native country? Perhaps; but how are we to know? Haricot, fantastic haricot, you set us a curious philological problem.

It is also known in French as faseole, or flageolet. The Provencal calls it faiou and faviou; the Catalan, fayol; the Spaniard, faseolo; the Portuguese, feyao; the Italian, fagiuolo. Here I am on familiar ground: the languages of the Latin family have preserved, with the inevitable modifications, the ancient word faseolus.

Now, if I consult my dictionary I find: faselus, faseolus, phaseolus, haricot. Learned lexicographer, permit me to remark that your translation is incorrect: faselus, faseolus cannot mean haricot. The incontestable proof is in the Georgics, where Virgil tells us at what season we must sow the faselus. He says:—

Si vero viciamque seres vilemque faselum ... Haud obscura cadens mittet tibi signa Bootes; Incipe, et ad medias sementem extende pruinas.

Nothing is clearer than the precept of the poet who was so admirably familiar with all matters agricultural; the sowing of the faselus must be commenced when the constellation of Bootes disappears at the set of sun, that is, in October; and it is to be continued until the middle of the winter.

These conditions put the haricot out of the running: it is a delicate plant, which would never survive the lightest frost. Winter would be fatal to it, even under Italian skies. More refractory to cold on account of the country of their origin, peas, broad beans, and vetches, and other leguminous plants have nothing to fear from an autumn sowing, and prosper during the winter provided the climate be fairly mild.

What then is represented by the faselus of the Georgics, that problematical vegetable which has transmitted its name to the haricot in the Latin tongues? Remembering that the contemptuous epithet vilis is used by the poet in qualification, I am strongly inclined to regard it as the cultivated vetch, the big square pea, the little-valued jaisso of the Provencal peasant.

The problem of the haricot stood thus, almost elucidated by the testimony of the insect world alone, when an unexpected witness gave me the last word of the enigma. It was once again a poet, and a famous poet, M. Jose-Maria de Heredia, who came to the aid of the naturalist. Without suspecting the service he was rendering, a friend of mine, the village schoolmaster, lent me a magazine[9] in which I read the following conversation between the master-sonneteer and a lady journalist, who was anxious to know which of his own works he preferred.

"What would you have me say?" said the poet.

"I do not know what to say, I do not know which sonnet I prefer; I have taken horrible pains with all of them.... But you, which do you prefer?"

"My dear master, how can I choose out of so many jewels, when each one is perfect in its beauty? You flash pearls, emeralds, and rubies before my astonished eyes: how should I decide to prefer the emerald to the pearl? I am transported by admiration of the whole necklace."