The Life of the fly Part 2

There are good people like that, only too happy to serve science with resounding appellations that might come from Timbuktu; they cannot name you a midge without striking terror into you. O ye wise and revered ones, ye christeners of animals, I am willing, in my study, to make use--but not undue use--of your harsh terminology, with its conglomeration of syllables; but there is a danger of their leaving the sanctum and appearing before the public, which is always ready to show its lack of deference for terms that do not respect its ears. I, wis.h.i.+ng to speak like everybody else, so that I may be understood by all, and persuaded that science has no need of this Brobdignagian jargon, make a point of avoiding technical nomenclature when it becomes too barbarous, when it threatens to lumber the page the moment my pen attempts it. And so I abandon Monodontomerus.

It is a puny little insect, almost as tiny as the midges whom we see eddying in a ray of suns.h.i.+ne at the end of autumn. Its dress is golden bronze; its eyes are coral red. It carries a naked sword, that is to say, the sheath of its drill stands out slantwise at the tip of its belly, instead of lying in a hollow groove along the back, as it does with the Leucospis. This scabbard holds the latter half of the inoculating filament, which extends below the animal to the base of the abdomen. In short, its utensil is that of the Leucospis, with this difference, that its lower half sticks out like a rapier.

This mite that bears a sword upon her rump is yet another persecutor of the mason bees and not one of the least formidable. She exploits their nests at the same time as the Leucospis. I see her, like the Leucospis, slowly explore the ground with her antennae; I see her, like the Leucospis, bravely drive her dagger into the stone wall. More taken up with her work, less conscious perhaps of danger, she pays no heed to the man who is observing her so closely. Where the Leucospis flies, she does not budge. So great is her a.s.surance that she comes right into my study, to my work table, and disputes my owners.h.i.+p of the nests whose occupants I am examining. She operates under my lens, she operates just beside my forceps. What risk does she run? What can one do to a thing so very small? She is so certain of her safety that I can take the Mason's nest in my hand, move it, put it down and take it up again without the insect's raising any objection: it continues its work even when my magnifying gla.s.s is placed over it.

One of these heroines has come to inspect a nest of the Chalicodoma of the Walls, most of whose cells are occupied by the numerous coc.o.o.ns of a parasite, the Stelis. The contents of these cells, which have been partially ripped up to satisfy my curiosity, are very much exposed to view. The windfall appears to be appreciated, for I see the dwarf ferret about from cell to cell for four days on end, see her choose her coc.o.o.n and insert her awl in the most approved fas.h.i.+on. I thus learn that sight, although an indispensable guide in searching, does not decide upon the proper spot for the operation. Here is an insect exploring not the stony exterior of the mason's dwelling, but the surface of coc.o.o.ns woven of silk. The explorer has never found herself placed in such circ.u.mstances, nor has any of her race before her, every coc.o.o.n, under normal conditions, being protected by a surrounding wall. No matter: despite the profound difference in the surfaces, the insect does not waver. Warned by a special sense, an undecipherable riddle to ourselves, it knows that the object of its search lies hidden under this unfamiliar casing. The sense of smell has already been shown to be out of the question; that of sight is now eliminated in its turn.

That she should bore through the coc.o.o.ns of the Stelis, a parasite of the mason bee, does not surprise me at all: I know how indifferent my bold visitor is to the nature of the victuals destined for her family. I have noticed her presence in the homes of bees differing greatly in size and habits: Anthophorae, Osmiae, Chalicodomae, Anthidia. The Stelis exploited on my table is one victim more; and that is all. The interest does not lie there. The interest lies in the maneuvers of the insect, which I am able to follow under the most favorable conditions.

Bent sharply at right angles, like a couple of broken matches, the antennae feel the coc.o.o.n with their tips alone. The terminal joint is the home of this strange sense which discerns from afar what no eye sees, no scent distinguishes and no ear hears. If the point explored be found suitable, the insect hoists itself on tiptoe so as to give full scope to the play of its mechanism; it brings the tip of the belly a little forward; and the entire ovipositor--inoculating-needle and scabbard--stands perpendicular to the coc.o.o.n, in the center of the quadrilateral described by the four hind legs, an eminently favorable position for obtaining the maximum effect. For some time, the whole of the awl bears on the coc.o.o.n, feeling all round with its point, groping about; then, suddenly, the boring needle is released from its sheath, which falls back along the body, while the needle strives to make its entrance. The operation is a difficult one. I see the insect make a score of attempts, one after the other, without succeeding in piercing the tough wrapper of the Stelis. Should the instrument not penetrate, it retreats into its sheath and the insect resumes its scrutiny of the coc.o.o.n, sounding it point by point with the tips of its antennae. Then further thrusts are tried until one succeeds.

The eggs are little spindles, white and gleaming like ivory, about two-thirds of a millimeter in length. They have not the long, curved peduncle of the Leucospis' eggs; they are not suspended from the ceiling of the coc.o.o.n like these, but are laid without order around the fostering larva. Lastly, in a single cell and with a single mother, there is always more than one laying; and the number of eggs varies considerably in each. The Leucospis, because of her great size, which rivals that of her victim, the Bee, finds in each cell provisions enough for one and one alone. When, therefore, there is more than one set of eggs in any one cell, this is due to a mistake on her part and not a premeditated result. Where the whole ration is required for the meals of a single grub, she would take good care not to install several if she could help it. Her compet.i.tor is not called upon to observe the same discretion. A Chalicodoma grub gives the dwarf the wherewithal to portion a score of her little ones, who will live in common and in all comfort on what a single son of the giantess would eat up by himself.

The tiny boring engineer, therefore, always settles a numerous family at the same banquet. The bowl, ample for a dozen or two, is emptied in perfect harmony.

Curiosity made me count the brood, to see if the mother was able to estimate the victuals and to proportion the number of guests to the sumptuousness of the fare provided. My notes mention fifty-four larvae in the cell of a masked Anthophora (Anthophora personata). No other census attained this figure. Possibly, two different mothers had laid their eggs in this crowded habitation. With the Mason bee of the Walls, I see the number of larvae vary, in different cells, between four and twenty-six; with the mason bee of the Sheds, between five and thirty-six; with the three-horned Osmia, who supplied me with the largest number of records, between seven and twenty-five; with the blue Osmia (Osmia cyanea, KIRB.), between five and six; with the Stelis (Stelis nasuta), between four and twelve.

The first return and the last two seem to point to some relation between the abundance of provisions and the number of consumers. When the mother comes upon the bountiful larva of the masked Anthophora, she gives it half-a-hundred to feed; with the Stelis and the blue Osmia, n.i.g.g.ardly rations both, she contents herself with half-a-dozen. To introduce into the dining room only the number of boarders that the bill of fare will allow would certainly be a most deserving performance, especially as the insect is placed under very difficult conditions to judge the contents of the cell. These contents, which lie hidden under the ceiling, are invisible; and the insect can derive its information only from the outside of the nest, which varies in the different species. We should therefore have to admit the existence of a particular power of discrimination, a sort of discernment of the species, which is recognized as large or small from the outward aspect of its house. I refuse to go to this length in my conjectures, not that instinct seems to me incapable of such feats, but because of the particulars obtained from the three-horned Osmia and the two mason bees.

In the cells of these three species, I see the number of larvae put out to nurse vary in so elastic a fas.h.i.+on that I must abandon all idea of proportionate adjustment. The mother, without troubling unduly whether there be an excess or a dearth of provisions for her family, has filled the cells as her fancy prompted, or rather according to the number of ripe ovules contained in her ovaries at the time of the laying. If food be over-plentiful, the brood will be all the better for it and will grow bigger and stronger; if food be scarce, the famished youngsters will not die, but will remain smaller. Indeed, with both the larva and the full grown insect, I have often observed a difference in size which varies according to the density of the population, the members of a small colony being double the size of their overcrowded neighbors.

The grubs are white, tapering at both ends, sharply segmented and covered all over their bodies with a coat of fine, soft hairs which is invisible except under the lens. The head consists of a little k.n.o.b much smaller in diameter than the body. In this head, the microscope reveals mandibles consisting of fine spikes of a tawny red, which spread into a wide, colorless base. Deprived of any indentation, incapable of chewing anything between their awl-shaped ends, these two tools serve at best to fix the grub slightly at some point of the fostering larva. Useless for carving, therefore, the mouth is a pure osculatory sucker, which drains the provisions by a process of exudation through the skin. We see here repeated what the Anthrax and the Leucospis have already shown us: the gradual exhaustion of a victim which the parasite consumes without killing it.

It is a curious spectacle even after that of the Anthrax. We have here twenty or thirty starvelings, all with their mouths pressed, as for a kiss, to the body of the plump larva, which, from day to day, fades and shrinks without the least appreciable wound, thus keeping fresh until reduced to a shriveled slough. If I disturb the gluttonous swarm, all, with a sudden recoil, let go, drop off and flounder around the foster mother. They are no less prompt in resuming their savage kisses. I need not add that neither at the point where they leave off nor at the point where they recommence is there the faintest trace of liquid. The oily exudation occurs only when the pump is at work. To linger over this strange method of feeding is superfluous after what I have said about the Anthrax.

The appearance of the full grown insect takes place at the beginning of summer, after nearly a whole year's stay in the invaded dwelling. The large number of inhabitants of one and the same cell led me to think that the work of deliverance ought to present a certain interest. They are all equally anxious to clear the walls of the prison at the earliest possible moment and to come forth into the great festival of the sun: do they all at the same time, in a confused horde, attack the ceiling which has to be pierced? Is the work of deliverance arranged in the general interest? Or is individual selfishness the only rule? These are the questions which observation will answer.

A little in advance of the proper season, I transfer each family into a short gla.s.s tube, which will represent the natal cell. A good, thick cork, quite a centimeter deep, is the obstacle to be pierced for an outlet. Well, instead of the mad haste and the ruinous lack of organization which I expected to find, my broods show me in their gla.s.s prison an exceedingly well regulated workshop. One insect, one only, works at perforating the cork. Patiently, with its mandibles, grain by grain, it digs a tunnel the width of its body. The gallery is so narrow that, in order to return to the tube, the worker has to move backwards.

It is a slow process; and it takes hours and hours to dig the hole, a hard job for the frail miner.

Should her fatigue become too great, the excavator leaves the forefront and mingles with the crowd, to polish and dust herself. Another, the first neighbor at hand, at once takes her place and is herself relieved by a third when her task is done. Others again take their turn, always one at a time, so much so that the works are never at a standstill and never overcrowded. Meanwhile, the mult.i.tude keeps out of the way, quietly and patiently. There is no anxiety as to the deliverance.

Success will come: of that they are all convinced. While waiting, one washes her antennae by pa.s.sing them through her mouth, another polishes her wings with her hind legs, another frisks about to while away the period of inaction. Some are making love, a sovran means of killing time, whether one be born that day or twenty years ago.

Some, I said, make love. These favored ones are rare; they hardly count.

Is it through indifference? No, but the gallants are lacking. The s.e.xes are very unequally represented in the population of a cell: the males are in a wretched minority and sometimes even completely absent. This poverty did not escape the older observers. Brulle [Gaspard August Brulle (1809-1873)], the author of many works on natural history and one of the founders of the Societe entomologique de France, the only author whom I am able to consult in my hermitage, says, literally: 'The males do not appear to be known.'

I, for my part, know them; but, considering their feeble number, I keep asking myself what part they play in a harem so disproportionate to their forces. A few figures will show us what my hesitations are based upon.

In twenty-two Osmia coc.o.o.ns (Osmia tricornis), the total census of the inmates yields three hundred and fifty-four, of whom forty-seven are males and three hundred and seven females. The average number of inmates, therefore, is sixteen individuals; and there are six females at least to one male. This disparity is maintained, in more or less marked proportions, whatever the species of the bee invaded. In the coc.o.o.ns of the Mason bee of the Sheds, I discover the average proportion to be six females to one male; in those of the Mason bee of the Walls, I find one male to fifteen females.

These facts, which I am unable to state with any greater precision, are enough to give rise to the suspicion that the males, who are even tinier dwarfs than the females and who, moreover, like all insects, are injured by a single act of pairing, must, in most cases, remain strangers to the females. Can the mothers, in fact, dispense with their a.s.sistance, without being deprived of offspring on that account? I do not say yes, but I do not say no. The duality of the s.e.xes is a hard problem. Why two s.e.xes? Why not just one? It would have been much simpler and saved a great deal of foolery. Why such a thing as s.e.x, when the tuber of the Jerusalem artichoke can do without it? These are the pregnant questions suggested to me, in the end, by Monodontomerus cupreus, the insect so infinitesimal in body and so overpowering in name that I had really vowed never to speak of it again by its official designation.

CHAPTER IV. LARVAL DIMORPHISM

If the reader has paid any attention to the story of the Anthrax, he must have perceived that my narrative is incomplete. The fox in the fable saw how the lion's visitors entered his den, but did not see how they went out. With us, it is the converse: we know the way out of the mason bee's fortress, but we do not know the way in. To leave the cell of which he has eaten the owner, the Anthrax becomes a perforating machine, a living tool from which our own industry might take a hint if it required new drills for boring rocks. When the exit tunnel is opened, this tool splits like a pod bursting in the sun; and from the stout framework there escapes a dainty fly, a velvety flake, a soft fluff that astounds us by its contrast with the roughness of the depths whence it ascends. On this point, we know pretty well what there is to know. There remains the entrance into the cell, a puzzle that has kept me on the alert for a quarter of a century.

To begin with, it is evident that the mother cannot lodge her egg in the cell of the mason bee, which has been long closed and barricaded with a cement wall by the time that the Anthrax makes her appearance. To penetrate it, she would have to become an excavating tool once more and resume the cast-off rags which she left behind in the exit window; she would have to retrace her steps, to be reborn a pupa; and life knows none of these retrogressions. The full grown insect, if endowed with claws, mandibles and plenty of perseverance, might at a pinch force the mortar casket; but the fly is not so endowed. Her slender legs would be strained and deformed by merely sweeping away a little dust; her mouth is a sucker for gathering the sugary exudations of the flowers and not the solid pincers needed for the crumbling of cement. There is no auger either, no bore copied from that of the Leucospis, no implement of any kind that can work its way into the thickness of the wall and dispatch the egg to its destination. In short, the mother is absolutely incapable of settling her eggs in the chamber of the Mason bee.

Can it be the grub that makes its own way into the storeroom, that same grub which we have seen draining the Chalicodoma with its leech-like kisses? Let us call the creature to mind: a little oily sausage, which stretches and curls up just where it lies, without being able to s.h.i.+ft its position. Its body is a smooth cylinder; its mouth simply a circular lip. Not one ambulatory organ does it possess; not even hairs, protuberances or wrinkles to enable it to crawl. The animal is made for digestion and immobility. Its organization is incompatible with movement; everything tells us so in the clearest fas.h.i.+on. No, this grub is even less able than the mother to make its way unaided into the mason's dwelling. And yet the provisions are there; those provisions must be reached: it is a matter of life or death; to be or not to be.

Then how does the fly set about it? It would be vain for me to question probabilities, too often illusory; to obtain a reply of any value, I have but one resource; I must attempt the nearly impossible and watch the Anthrax from the egg onwards.

Although Anthrax flies are fairly common, in the sense of there being several different species, they are not plentiful when it is a case of wanting a colony populous enough to admit of continuous observation.

I see them, now here, now there, in the fiercely sun-scorched places, flitting hither and thither on the old walls, the slopes and the sand, sometimes in small platoons, most often singly. I can expect nothing of those vagabonds, who are here today and gone tomorrow, for I know nothing of their settlements. To keep a watch on them, one by one, in the blazing heat, is very painful and very unfruitful, as the swift-winged insect has a habit of disappearing one knows not whither just when a prospect of capturing its secret begins to offer. I have wasted many a patient hour at this pursuit, without the least result.

There might be some chance of success with Anthrax flies whose home was known to us beforehand, especially if insects of the same species formed a pretty numerous colony. The inquiries begun with one would be continued with a second and with more, until a complete verdict was forthcoming. Now, in the course of my long entomological career, I have met with but two species of Anthrax that fulfilled this condition and were to be found regularly: one at Carpentras; the other at Serignan.

The first, Anthrax sinuata, FALLEN, lives in the coc.o.o.ns of Osmia tricornis, who herself builds her nest in the old galleries of the hairy-footed Anthophora; the second, Anthrax trifasciata, MEIGEN, exploits the Chalicodoma of the Sheds. I will consult both.

Once more, here am I, somewhat late in life, at Carpentras, whose rude Gallic name sets the fool smiling and the scholar thinking. Dear little town where I spent my twentieth year and left the first bits of my fleece upon life's bushes, my visit of today is a pilgrimage; I have come to lay my eyes once more upon the place which saw the birth of the liveliest impressions of my early days. I bow, in pa.s.sing, to the old college where I tried my prentice hand as a teacher. Its appearance is unchanged; it still looks like a penitentiary. Those were the views of our mediaeval educational system. To the gaiety and activity of boyhood, which were considered unwholesome, it applied the remedy of narrowness, melancholy and gloom. Its houses of instruction were, above all, houses of correction. The freshness of Virgil was interpreted in the stifling atmosphere of a prison. I catch a glimpse of a yard between four high walls, a sort of bear pit, where the scholars fought for room for their games under the spreading branches of a plane tree. All around were cells that looked like horse boxes, without light or air; those were the cla.s.srooms. I speak in the past tense, for doubtless the present day has seen the last of this academic dest.i.tution.

Here is the tobacco shop where, on Wednesday evening, coming out of the college, I would buy on credit the wherewithal to fill my pipe and thus to celebrate on the eve the joys of the morrow, that blessed Thursday [the weekly half-holiday in French schools] which I considered so well employed in solving hard equations, experimenting with new chemical reagents, collecting and identifying my plants. I would make my timid request, pretending to have come out without my money, for it is hard for a self-respecting man to admit that he is penniless. My candor appears to have inspired some little confidence; and I obtained credit, an unprecedented thing, with the representative of the revenue. [The government in France has the sole control of the tobacco trade, which forms an important branch of the inland revenue.] Ah, why did not I open a shop and expose for sale some packets of candles, a dozen dried cod, a barrel of sardines and a few cakes of soap! I am no more of a fool nor any less industrious than another; and I should have made my way. But, as it was, what could I expect? As an accoucheur of brains, a molder of intellects, I had no claim even to bread and cheese.

Here is my former habitation, occupied since by droning monks. In the embrasure of that window, sheltered from profane hands, between the closed outer shutters and the panes, I used to keep my chemicals, bought for a few sous cheated out of the weekly budget in the early days of our housekeeping. The bowl of a pipe was my crucible, a sweet jar my retort, mustard pots my receptacles for oxides and sulfides. My experiments, harmless or dangerous, were made on a corner of the fire beside the simmering broth.

How I should love to see that room again where I pored over differentials and integrals, where I calmed my poor burning head by gazing at Mont Ventoux, whose summit held in store for my coming expedition' those denizens of arctic climes, the saxifrage and the poppy! And to see my familiar friend, the blackboard which I hired at five francs a year from a crusty joiner, that board whose value I paid many times over, though I. could never buy it outright, for want of the necessary cas.h.!.+ The conic sections which I described on that blackboard, the learned hieroglyphics!

Though all my efforts, which were the more deserving because I had to work alone, led to almost nothing in that congenial calling, I would begin it all over again if I could. I should love to be conversing for the first time with Leibnitz and Newton, with Laplace and Lagrange, with Cuvier and Jussieu, even if I had afterwards to solve that other arduous problem: how to procure one's daily bread. Ah, young men, my successors, what an easy time you have of it today! If you don't know it, then let me tell you so by means of these few pages from the life of one of your elders.

But let us not forget our insects, while listening to the echoes of illusions and difficulties roused in my memories by the cupboard window and the hired blackboard. Let us go back to the sunken roads of the Legue, which have become cla.s.sic, so they say, since the appearance of my notes on the Oil beetles. Ye ill.u.s.trious ravines, with your sun-baked slopes, if I have contributed a little to your fame, you, in your turn, have given me many fair hours of forgetfulness in the happiness of learning. You, at least, did not lure me with vain hopes; all that you promised you gave me and often a hundredfold. You are my promised land, where I would have sought at the last to pitch my observer's tent. My wish was not to be realized. Let me, at least, in pa.s.sing, greet my beloved animals of the old days.

I raise my hat to Cerceris tuberculata, whom I see engaged on that slant, storing her Cleonus [a large species of weevil]. As I saw her then, so I see her now: the same staggering attempts to hoist the prey to the mouth of the burrow; the same brawls between males watching in the brushwood of the kermes oak. The sight of them sends a younger blood coursing through my veins; I receive as it were the breath of a new springtime of life. Time presses; let us pa.s.s on.

Another bow on this side. I hear buzzing up above, on that ledge, a colony of Sphex wasps, stabbing their crickets. We will give them a friendly glance, but no more. My acquaintances here are too numerous; I have not the leisure to renew my former relations with all of them.

Without stopping, a wave of the hat to the Philanthi [bee-hunting wasps]

who send the long avalanches of rubbish streaming down from their nests; and to Stizus ruficornis, [a hunting wasp] who stacks her praying mantises between two flakes of sandstone; and to the silky Ammophila [a digger wasp] with the red legs, who collects an underground store of loopers [also known as measuring worms, the larvae or caterpillars of the geometrid moth] and to the Tachtyti [hunting wasps], devourers of locusts; and to the Eumenes, builders of clay cupolas on a bough.

Here we are at last. This high, perpendicular rock, facing the south to a length of some hundreds of yards and riddled with holes like a monstrous sponge, is the time-honored dwelling place of the hairy-footed Anthophora and of her rent free tenant, the three-horned Osmia. Here also swarm their exterminators: the Sitaris beetle, the parasite of the Anthophora; the Anthrax fly, the murderer of the Osmia. Ill informed as to the proper period, I have come rather late, on the 10th of September.

I should have been here a month ago, or even by the end of July, to watch the fly's operations. My journey threatens to be fruitless: I see but a few rare Anthrax flies, hovering round the face of the cliff. We will not despair, however, and we will begin by consulting the locality.

The Anthophora's cells contain this bee in the larval stage. Some of them provide me with the oil beetle and the Sitaris, rare finds at one time, today of no use to me. Others contain the Melecta [a parasitic bee] in the form of a highly colored pupa, or even in that of the full grown insect. The Osmia, still more precocious, though dating from the same period, shows herself exclusively in the adult form, a bad omen for my investigations, for what the Anthrax demands is the larva and not the perfect insect. The fly's grub doubles my apprehensions. Its development is complete, the larva on which it feeds is consumed, perhaps several weeks ago. I no longer doubt but that I have come too late to see what happens in the Osmia's coc.o.o.ns.

Is the game lost? Not yet. My notes contain evidence of Anthrax flies hatching in the latter half of September. Besides, those whom I now see exploring the rock are not there to take exercise: their preoccupation is the settling of the family. These belated ones cannot tackle the Osmia, who, with her firm, adult flesh, would not suit the nursling's delicate needs and who, moreover, powerful as she is, would offer resistance. But in autumn a less numerous colony of honey gatherers takes the place, upon the slope, of the spring colony, from which it differs in species. In particular, I see the Diadem Anthidium [a clothier bee who lines her nest with wool and cotton] at work, entering her galleries at one time with her harvest of pollen dust and at another with her little bale of cotton. Might not these autumnal Bees be themselves exploited by the Anthrax, the same that selected the Osmia as her victim a couple of months earlier? This would explain the presence of the Anthrax flies whom I now see fussing about.

A little rea.s.sured by this conjecture, I take my stand at the foot of the rock, under a broiling sun; and, for half a day, I follow the evolutions of my flies. They flit quietly in front of the slope, at a few inches from the earthy covering. They go from one orifice to the next, but without even penetrating. For that matter, their big wings, extended crosswise even when at rest, would resist their entrance into a gallery, which is too narrow to admit those spreading sails. And so they explore the cliff, going to and fro and up and down, with a flight that is now sudden, now smooth and slow. From time to time, I see the Anthrax quickly approach the wall and lower her abdomen as though to touch the earth with the end of her ovipositor. This proceeding takes no longer than the twinkling of an eye. When it is done, the insect alights elsewhere and rests. Then it resumes its sober flight, its long investigations and its sudden blows with the tip of its belly against the layer of earth. The Bombylii [bee flies] observe similar tactics when soaring at a short height above the ground.

I at once rushed to the spot touched, lens in hand, in the hope of finding the egg which everything told me was laid during that tap of the abdomen. I could distinguish nothing, in spite of the closest attention.

It is true that my exhaustion, together with the blinding light and scorching heat, made examination very difficult. Afterwards, when I made the acquaintance of the tiny thing that issues from that egg, my failure no longer surprised me. In the leisure of my study, with my eyes rested and with my most powerful gla.s.ses held in a hand no longer shaking with excitement and fatigue, I have the very greatest difficulty in finding the infinitesimal creature, though I know exactly where it lies. Then how could I see the egg, worn out as I was under the sun-baked cliff, how discover the precise spot of a laying performed in a moment by an insect seen only at a distance? In the painful conditions wherein I found myself, failure was inevitable.

Despite my negative attempts, therefore, I remain convinced that the Anthrax flies strew their eggs one by one, on the spots frequented by those bees who suit their grubs. Each of their sudden strokes with the tip of the abdomen represents a laying. They take no precaution to place the germ under cover; for that matter, any such precaution would be rendered impossible by the mother's structure. The egg, that delicate object, is laid roughly in the blazing sun, between grains of sand, in some wrinkle of the calcined chalk. That summary installation is sufficient, provided the coveted larva be near at hand. It is for the young grub now to manage as best it can at its own risk and peril.

Though the sunken roads of the Legue did not tell me all that I wished to know, they at least made it very probable that the coming grub must reach the victualled cell by its own efforts. But the grub which we know, the one that drains the bag of fat which may be a Chalicodoma larva or an Osmia larva, cannot move from its place, still less indulge in journeys of discovery through the thickness of a wall and the web of a coc.o.o.n. So an imperative necessity presents itself: there must perforce be an initial larva form, capable of moving and organized for searching, a form under which the grub would attain its end. The Anthrax would thus possess two larval states: one to penetrate to the provisions; the other to consume them. I allow myself to be convinced by the logic of it all; I already see in my mind's eye the wee animal coming out of the egg, endowed with sufficient power of motion not to dread a walk and with sufficient slenderness to glide into the smallest crevices. Once in the presence of the larva on which it is to feed, it doffs its travelling dress and becomes the obese animal whose one duty it is to grow big and fat in immobility. This is all very coherent; it is all deduced like a geometrical proposition. But to the wings of imagination, however smooth their flight, we must prefer the sandals of observed facts, the slow sandals with the leaden soles. Thus shod, I proceed.

Next year, I resume my investigations, this time on the Anthrax of the Chalicodoma, who is my neighbor in the surrounding wastelands and will allow me to repeat my visits daily, morning and evening if need be.

Taught by my earlier studies, I now know the exact period of the Bee's hatching and therefore of the Anthrax' laying, which must take place soon after. Anthrax trifasciata settles her family in July, or in August at latest. Every morning, at nine o'clock, when the heat begins to be unendurable and when, to use [the author's gardener and factotum]

Favier's expression, an extra log is flung on the bonfire of the sun, I take the field, prepared to come back with my head aching from the glare, provided that I bring home the solution of my puzzle. A man must have the devil in him to leave the shade at this time of the year. And what for, pray? To write the story of a fly! The greater the heat, the better my chance of success. What causes me to suffer torture fills the insect with delight; what prostrates me braces the fly. Come along!

The road s.h.i.+mmers like a sheet of molten steel. From the dusty and melancholy olive trees rises a mighty, throbbing hum, a great andante whose executants have the whole sweep of woods for their orchestra. 'Tis the concert of the Cicada, whose bellies sway and rustle with increasing frenzy as the temperature rises. The strident sc.r.a.pings of the Cicada of the Ash, the Carcan of the district, lend their rhythm to the one note symphony of the common cicada. This is the moment: come along! And, for five or six weeks, oftenest in the morning, sometimes in the afternoon, I set myself to explore the flinty plateau.