THE LOCUSTS: THE LAST MOULT

The Life of the Grasshopper by Jean-Henri Fabre, is part of the HackerNoon Books Series. You can jump to any chapter in this book here. THE LOCUSTS: THE LAST MOULT

CHAPTER XIX. THE LOCUSTS: THE LAST MOULT

I have just beheld a stirring sight: the last moult of a Locust, the extraction of the adult from his larval wrapper. It is magnificent. The object of my enthusiasm is the Grey Locust, the giant among our Acridians, who is common on the vines at vintage-time, in September. On account of his size—he is as long as my finger—he is a better subject for observation than any other of his tribe.

The fat, ungraceful larva, a rough draft of the perfect insect, is usually pale-green; but some also are bluish-green, dirty-yellow, red-brown or even ashen-grey, like the grey of the adult. The corselet is strongly keeled and notched, with a sprinkling of fine white worm-holes. The hind-legs, powerful as those of mature age, have a great haunch striped with red and a long shank shaped like a two-edged saw.[402]

The wing-cases, which in a few days will project well beyond the tip of the abdomen, are in their present state two skimpy, triangular pinions, touching back to back along their upper edges and continuing the keel of the corselet. Their free ends stand up like a pointed gable. These two coat-tails, of which the material seems to have been clipped short with ridiculous meanness, just cover the creature’s nakedness at the small of the back. They shelter two lean strips, the germs of the wings, which are even more exiguous. In brief, the sumptuous, slender sails of the near future are at present sheer rags, of such meagre dimensions as to be grotesque. What will come out of these miserable envelopes? A marvel of stately elegance.

Let us observe the proceedings in detail. Feeling itself ripe for transformation, the creature clutches the trelliswork of the cage with its hinder and intermediary legs. The fore-legs are folded and crossed over the breast and are not employed in supporting the insect, which hangs in a reversed position, back downwards. The triangular pinions, the sheaths of the wing-cases, open their peaked roof and separate sideways; the two [403]narrow strips, the germs of the wings, stand in the centre of the uncovered space and diverge slightly. The position for the moult has now been taken with the necessary stability.

The first thing to be done is to burst the old tunic. Behind the corselet, under the pointed roof of the prothorax, pulsations are produced by alternate inflation and deflation. A similar operation is performed in front of the neck and probably also under the entire covering of the shell that is to be split. The delicacy of the membranes at the joints enables us to perceive what is going on at these bare points, but the harness of the corselet hides it from us in the central portion.

It is there that the insect’s reserves of blood flow in waves. The rising tide expresses itself in blows of an hydraulic battering-ram. Distended by this rush of humours, by this injection wherein the organism concentrates its energies, the skin at last splits along a line of least resistance prepared by life’s subtle previsions. The fissure yawns all along the corselet, opening precisely over the keel, as though the two symmetrical halves had been soldered. Unbreakable [404]any elsewhere, the wrapper yields at this median point which is kept weaker than the rest. The split is continued some little way back and runs between the fastenings of the wings; it goes up the head as far as the base of the antennæ, where it sends a short ramification to the right and left.

Through this break the back is seen, quite soft, pale, hardly tinged with grey. Slowly it swells into a larger and larger hunch. At last it is wholly released. The head follows, extracted from its mask, which remains in its place, intact in the smallest particular, but looking strange with its great glassy eyes that do not see. The sheaths of the antennæ, with not a wrinkle, with nothing out of order and with their normal position unchanged, hang over this dead face, which is now translucent.

Therefore, in emerging from their narrow sheaths, which enclosed them with such absolute precision, the antennary threads encountered no resistance capable of turning their scabbards inside out, or disturbing their shape, or even wrinkling them. Without injuring the twisted containers, the contents, equal in size and themselves twisted, have managed to slip out as easily as a smooth, [405]straight object would do, if sliding in a loose sheath. The extraction-mechanism will be still more remarkable in the case of the hind-legs.

Meanwhile it is the turn of the fore-legs and then of the intermediary legs to shed armlets and gauntlets, always without the least rent, however small, without a crease of rumpled material, without a trace of any change in the natural position. The insect is now fixed to the top of the cage only by the claws of the long hind-legs. It hangs perpendicularly, head downwards, swinging like a pendulum, if I touch the wire-gauze. Four tiny hooks are what it hangs by. If they gave way, if they became unfastened, the insect would be lost, for it is incapable of unfurling its enormous wings anywhere except in space. But they will hold: life, before withdrawing from them, left them stiff and solid, so as to be able firmly to support the struggles that are to follow.

The wing-cases and wings now emerge. These are four narrow strips, faintly grooved and looking like bits of paper ribbon. At this stage, they are scarcely a quarter of their final length. So limp are they that they bend under their own weight [406]and sprawl along the insect’s sides in the opposite direction to the normal. Their free end, which should be turned backwards, now points towards the head of the Locust, who is hanging upside down. Imagine four blades of thick grass, bent and battered by a rainstorm, and you will have a fair picture of the pitiable bunch formed by the future organs of flight.

It must be no light task to bring things to the requisite stage of perfection. The deeper-seated changes are already well-started, solidifying liquid mucilages, bringing order out of chaos; but so far nothing outside betrays what is happening in that mysterious laboratory where everything seems lifeless.

Meanwhile, the hind-legs become released. The great thighs appear in view, tinted on their inner surface with a pale pink, which will soon turn into a streak of bright crimson. The emergence is easy, the bulky haunch clearing the way for the tapering knuckle.

It is different with the shank. This, in the adult insect, bristles throughout its length with a double row of hard, pointed spikes. Moreover, the lower extremity ends in four large spurs. It is a genuine saw, but [407]with two parallel sets of teeth and so powerful that, if we dismiss the size from our minds, it might be compared with the rough saw wielded by a quarryman.

The larva’s shin is similarly constructed, so that the object to be extracted is contained in a sheath as awkwardly shaped as itself. Each spur is enclosed in a similar spur, each tooth fits into the hollow of a similar tooth; and the moulding is so exact that we should obtain no more intimate contact if, instead of the envelope waiting to be shed, we coated the limb with a layer of varnish distributed uniformly with a fine brush.

Nevertheless the sawlike tibia slips out of its long, narrow case without catching in it at any point whatever. If I had not seen this happen over and over again, I could never have believed it: the discarded legging is quite intact all the way down. Neither the terminal spurs nor the two rows of spikes have caught in the delicate mould. The saw has respected the dainty scabbard which a puff of my breath is enough to tear; the formidable rake has slipped through without leaving the least scratch behind it.

I was far from expecting such a result as [408]this. Because of the spiked armour, I imagined that the leg would strip in scales which came loose of themselves or yielded to rubbing, like dead cuticle. How greatly did the reality exceed my expectations!

From the spurs and spikes of the infinitely thin matrix there emerge spurs and spikes that make the leg capable of cutting soft wood. This is done without violence or the least inconvenience; and the discarded garment remains where it is, hanging by the claws to the top of the cage, uncreased and untorn. The magnifying-glass shows not a trace of rough usage. As the thing was before the excoriation, so it remains afterwards. The legging of dead skin continues, down to the pettiest details, an exact replica of the live leg.

If any one suggested that we should extract a saw from some sort of goldbeater’s-skin sheath which had been exactly moulded on the steel and that we should perform the operation without producing the least tear, we should burst out laughing: the thing is so flagrantly impossible. Life makes light of these impossibilities; it has methods of realizing the absurd, in case of need. And the Locust’s leg tells us so.[409]

If the saw of the shin were as hard as it is once it leaves its sheath, it would absolutely refuse to come out without tearing to pieces the tight-fitting scabbard. The difficulty therefore is evaded, for it is essential that the leggings, which form the only suspension-cords, should remain intact in order to furnish a firm support until the deliverance is completed.

The leg in process of liberation is not a limb fit for walking; it has not the rigidity which it will presently possess. It is soft and highly flexible. In the portion which the progress of the moult exposes to view, I see it bending and curving as I wish, under the mere influence of its own weight, when I lift the cage. It is as supple as elastic cord. And yet consolidation follows very rapidly, for the proper stiffness will be acquired in a few minutes.

Farther on, in the part hidden from me by the sheath, the leg is certainly softer and in a state of exquisite plasticity—I was almost saying fluidity—which allows it to overcome difficult passages almost as a liquid would flow.

The teeth of the saw are there, but have none of their future sharpness. I am able [410]to strip a leg partially with the point of a knife and to extract the spines from their horny mould. They are germs of spikes, flexible buds which bend under the slightest pressure and resume their upright position as soon as the pressure is removed.

These spikes lie backwards when the leg is about to be drawn out; they stand up again and solidify while it emerges. I am witnessing not the mere stripping of gaiters from limbs completely enclosed, but rather a sort of birth and growth which disconcert us by their rapidity.

Much in the same way, but with far less delicate precision, do the claws of the Crayfish, at moulting-time, withdraw the soft flesh of their two fingers from the old stony sheath.

The shanks are free at last. They are folded limply in the groove of the thigh, there to mature without moving. The abdomen is next stripped. Its fine tunic wrinkles, rumples and pushes back towards the extremity, which alone for some time longer remains clad in the moulting skin. Except at this point, the whole of the Locust is now bare.

It is hanging perpendicularly, head down, [411]supported by the claws of the now empty leggings. Throughout this long and finikin work, the four talons have never yielded, thanks to the delicacy and care with which the extraction has been conducted.

The insect, fixed by the stern to its cast skin, does not move. Its abdomen is immensely swollen, apparently distended by the reserve of organizable humours which the expansion of the wings and wing-cases will soon set in motion. The Locust is resting; he is recovering from his exertions. Twenty minutes are spent in waiting.

Then, by an effort of its back, the hanging insect raises itself and with its front tarsi grabs hold of the cast skin fastened above it. Never did acrobat, swinging by his feet from the bar of a trapeze, display greater strength of loin in lifting himself. When this feat is accomplished, what remains to be done is nothing. With the support which he has now gripped, the Locust climbs a little higher and reaches the wire gauze of the cage. This takes the place of the brushwood which the free insect would utilize for the transformation. He fixes himself to it with his four front feet. Then the tip of the abdomen succeeds in releasing itself, [412]whereupon, loosened with one last shake, the empty husk drops to the ground.

The fact of its falling interests me, for I remember the stubborn persistency with which the Cicada’s cast skin defies the winter winds without being detached from its supporting twig. The Locust’s transfiguration is conducted in much the same way as the Cicada’s. Then how is it that the Acridian gives himself such very shaky hangers? The hooks hold so long as the work of tearing continues, though one would think that this ought to bring down everything; they give way under a trifling shock so soon as that work is done. We have, therefore, a very unstable condition of equilibrium here, showing once more with what delicate precision the insect leaves its sheath.

I said “tearing,” for want of a better word. But it is not quite that. The term implies violence; and violence there cannot be any, because of the unsteady balance. Should the Locust, upset by his exertions, come to the ground, it would be all up with him. He would shrivel where he lies; or, at any rate, his organs of flight, being unable to expand, would remain pitiful shreds. The Locust does not tear himself loose; he [413]flows softly from his scabbard. It is as though he were forced out by a gentle spring.

To return to the wings and wing-cases, which have made no apparent progress since leaving the sheaths. They are still stumps, with fine longitudinal seams, not much more than bits of rope. Their expansion, which will take more than three hours, is reserved for the end, when the insect is completely stripped and in its normal position.

We have seen the Locust turn head uppermost. This upright position is enough to restore the natural arrangement of the wing-cases and wings. Being extremely flexible and bent by their own weight, they were hanging down with their loose end pointing towards the head of the inverted insect. Now, still by virtue of their own weight, they are straightened and put the right way up. They are no longer curved like the petals of a flower, they are no longer in an inverted position; but they still look miserably insignificant.

In its perfect state, the wing is fan-shaped. A radiating cluster of strong nervures runs through it lengthwise and forms the framework of the fan, which is readily furled or [414]unfurled. The intervening spaces are crossed by innumerable tiny bars which make of the whole a network of rectangular meshes. The wing-case, which is coarser and much less expanded, repeats this structure in squares.

In neither case does any of the mesh show during the rope’s-end stage. All that we see is a few wrinkles, a few winding furrows, which tell us that the stumps are bundles of cunningly folded material reduced to their smallest volume.

The expansion begins near the shoulder. Where at first nothing definite was to be distinguished, we soon see a diaphanous area subdivided into meshes of exquisite precision. Little by little, with a slowness that defies observation even through the magnifying-glass, this area increases in extent at the expense of the shapeless terminal roll. My eyes linger in vain on the confines of the two portions, the roll developing and the gauze already developed: I see nothing, see no more than I should see in a sheet of water. But wait a moment; and the tissue of squares stands out with perfect clearness.

If we judged only by this first examination, we should really think that an organizable [415]fluid is abruptly congealing into a network of nervures; we should imagine that we were in the presence of a crystallization similar, in its suddenness, to that of a saline solution on the slide of a microscope. Well, no: things cannot be actually happening like that. Life does not perform its tasks so hastily.

I detach a half-developed wing and turn the powerful eye of the microscope upon it. This time I am satisfied. On the confines where the network seemed to be gradually woven, that network was really in existence. I can plainly see the longitudinal nervures, already thick and strong; and I can also see, pale, it is true, and without relief, the cross-bars. I find them all in the terminal roll, of which I succeed in unfolding a few strips.

It is obvious. The wing is not at this moment a fabric on the loom, through which the procreative energies are driving their shuttle; it is a fabric already completed. All that it lacks to be perfect is expansion and stiffness, even as our linen needs only starching and ironing.

The flattening out is finished in three hours or more. The wings and wing-cases stand up on the Locust’s back like a huge set of [416]sails, sometimes colourless, sometimes pale-green, as are the Cicada’s wings at the beginning. We are amazed at their size when we think of the paltry bundles that represented them at first. How did so much stuff manage to find room there!

The fairy-tales tell us of a grain of hemp-seed that contained the underlinen of a princess. Here is a grain that is even more astonishing. The one in the story took years and years to sprout and multiply and at last to yield the quantity of hemp required for the trousseau; the Locust’s supplies a sumptuous set of sails in a short space of time.

Slowly the proud crest, standing erect in four straight blades, acquires consistency and colour. The latter turns the requisite shade on the following day. For the first time the wings fold like a fan and lie in their places; the wing-cases lower their outer edge and form a gutter which falls over the sides. The transformation is finished. All that remains for the big Locust to do is to harden his tissues still further and to darken the grey of his costume while revelling in the sun. Let us leave him to enjoy himself and retrace our steps a little.[417]

The four stumps, which issued from their sheaths shortly after the corselet split its keel down the middle, contain, as we have seen, the wings and wing-cases, with their network of nervures. This network, if not perfect, has at least the general plan of its numberless details mapped out. To unfurl these poor bundles and convert them into generous sails, it is enough that the organism, acting in this case like a forcing-pump, should shoot a stream of humours, which have been kept in reserve for this moment, the hardest of all, into the little channels already prepared for their reception. With the channel marked out in advance, a slight injection is sufficient to explain the rapid spread.

But what were the four strips of gauze while still contained in their sheaths? Are the wings spatules and the three-cornered pinions of the larva moulds whose creases, corners and sinuosities shape their contents in their own image and weave the tissues of the future wing and wing-case? If we had to do with a real instance of moulding, our brains could call a halt. We should say to ourselves that it was quite simple for the thing moulded to correspond with the shape [418]of the mould. But our halt would be short-lived, for the mould in its turn would want explaining: we should have to seek for a solution of its infinite intricacies. Let us not go so far back; we should be utterly in the dark. Let us rather keep to facts that can be observed.

I examine through the magnifying-glass a pinion of a larva ripe for transformation. I see a bundle of fairly thick nervures radiating fanwise. Other nervures, paler and finer, are set in the intermediate spaces. Lastly, the fabric is completed by a number of very short transversal lines, more delicate still and chevron-shaped.

This, no doubt, gives a rough outline of the future wing-case; but how different from the mature structure! The arrangement of the radiating nervures, the skeleton of the edifice, is not at all the same; the network formed by the transversal veins in no way suggests the complicated pattern which we shall see later. The rudimentary is about to be succeeded by the infinitely complex, the crude by the exquisitely perfect. The same remark applies to the wing-spatule and its outcome, the final wing.

It is quite evident, when we have the preparatory [419]and the ultimate stage before our eyes at the same time: the larva’s pinion is not merely a mould which elaborates the material in its own image and shapes the wing-case upon the model of its hollow. No, the membrane which we are expecting is not yet inside in the form of a bundle which, when unfurled, will astonish us with the size and the extreme complexity of its texture. Or, to be accurate, it is there, but in a potential state. Before becoming a real thing, it is a virtual thing, which is nothing as yet, but which is capable of becoming something. It is there just as much as the oak is inside its acorn.

A fine, transparent rim binds the free edge both of the embryo wing and the embryo wing-case. Under a powerful lens we can see a few uncertain outlines of the future lacework. This might well be the factory in which life intends to set its materials going. There is nothing else visible, nothing to suggest the prodigious network whose every mesh will shortly have its form and place determined for it with geometrical precision.

There must therefore be something better and greater than a mould to make the organizable [420]matter shape itself into a sheet of gauze and describe the inextricable labyrinth of the nervation. There is a primary plan, an ideal pattern which assigns to each atom its precise place. Before the matter begins to move, the configuration is already virtually traced, the courses of the plastic currents are already marked out. The stones of our buildings are arranged in accordance with the architect’s considered plan; they form an ideal assemblage before existing as a real assemblage. Similarly, a Locust’s wing, that sumptuous piece of lace emerging from a miserable sheath, speaks to us of another Architect, the Author of the plans which life must follow in its labours.

The genesis of living creatures offers to our contemplation, in an infinity of ways, marvels far greater than those of the Acridian; but generally they pass unperceived, overshadowed as they are by the veil of time. The lapse of years, with its slow mysteries, robs us of the most astonishing spectacles, unless our minds be endowed with a stubborn patience. Here, by exception, things take place with a swiftness that arrests even a wavering attention.

He who would, without wearisome delays, [421]catch a glimpse of the inconceivable dexterity with which life does its work has but to go to the great Locust of the vines. The insect will show him that which, with their extreme slowness, the sprouting seed, the budding leaf and the blossoming flower hide from our curiosity. We cannot see a blade of grass grow; but we can easily witness the growth of a Locust’s wings and wing-cases.

We stand astounded at this sublime phantasmagoria of a grain of hemp-seed which in a few hours becomes a superb piece of linen. What a proud artist is life, driving its shuttle to weave the wings of a Locust, one of those insignificant insects of which Pliny, long ago said:

“In his tam parvis, fere nullis, quæ vis, quæ sapientia, quam inextricabilis perfectis!”

How well the old naturalist was inspired on this occasion! Let us repeat after him:

“What power, what wisdom, what indescribable perfection in the tiny corner of life which the Locust of the vines has shown us!”

I have heard that a learned enquirer, to whom life was but a conflict of physical and [422]chemical forces, did not despair of one day obtaining artificial organizable matter: protoplasm, as the official jargon has it. Were it in my power, I should hasten to satisfy this ambitious person.

Very well, be it so: you have thoroughly prepared your protoplasm. By dint of long hours of meditation, deep study, scrupulous care and inexhaustible patience, your wishes have been fulfilled; you have extracted from your apparatus an albuminous glair, which goes bad easily and stinks like the very devil in a few days’ time: in short, filth. What do you propose to do with your product?

Will you organize it? Will you give it the structure of a living edifice? Will you take a hypodermic syringe and inject it between two impalpable films to obtain were it only the wing of a Gnat?

For that is more or less what the Locust does. He injects his protoplasm between the two scales of the pinion; and the material becomes a wing-case, because it finds as a guide the ideal archetype of which I spoke just now. It is controlled in its intricate windings by a plan which existed before the injection, before the material itself.[423]

Have you this archetype, this coordinator of forms, this primordial regulator, at the end of your syringe? No? Then throw away your product! No life will ever spring from that chemical ordure.

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