THE CLYTHRÆ: THE EGG

The Glow-Worm and Other Beetles by Jean-Henri Fabre, is part of the HackerNoon Books Series. You can jump to any chapter in this book here. THE CLYTHRÆ: THE EGG

CHAPTER XIX. THE CLYTHRÆ: THE EGG

Let us leave the long-armed and short-armed to pursue their amorous contests as they please and come to the egg, the main object of my insect-rearing. The Taxicorn Clythra is the first in the field; I see her at working during the last days of May. A most singular and disconcerting batch of eggs is hers! Is it really a group of eggs? I hesitate until I surprise the mother using her hind-legs to finish extracting the strange germ which issues slowly and perhaps laboriously from her oviduct.

It is indeed the Taxicorn Clythra's batch. Assembled in bundles of one to three dozen and each fastened by a slender transparent thread slightly longer than itself, the eggs form a sort of inverted umbel, which dangles sometimes from the trelliswork of the cover, sometimes from the leaves of the twigs that provide the grub with food. The bunch of grains quivers at the least breath.

We know the egg-cluster of the Hemerobius, the object of so many mistakes to the untrained observer. The little Lace-winged Fly with the gold eggs sets up on a leaf a group of long, tiny columns as fine as a spider's thread, each bearing an egg as a capital. The whole resembles pretty closely a tuft of some long-stemmed mildew. Remember also the Eumenes' hanging egg,1 which swings at the end of a thread, thus protecting the grub when it takes its first mouthfuls of the heap of dangerous game. The Taxicorn Clythra provides us with a third example of eggs fitted with suspension-threads, but so far nothing has given me an inkling of the function or the use of this string. Though the mother's intentions escape me, I can at least describe her work in some detail.

1 Cf. The Mason-wasps: chap. i.—Translator's Note.

The eggs are smooth, coffee-coloured and shaped like a thimble. If you hold them to the light, you see in the thickness of their skin five circular zones, darker than the rest and producing almost the same effect as the hoops of a barrel. The end attached to the suspension-thread is slightly conical; the other is lopped off abruptly and the section is hollowed into a circular mouth. A good lens shows us inside this, a little below the rim, a fine white membrane, as smooth as the skin of a drum.

In addition, from the edge of the orifice there rises a wide membranous tab, whitish and delicate, which might be taken for a raised lid. Nevertheless there is no raising of a lid after the eggs are laid. I have seen the egg leave the oviduct; it is then what it will be later, but lighter in colour. No matter: I cannot believe that so complicated a machine can make its way, with all sail set, through the maternal straits. I imagine that the lid-like appendage remains lowered, closing the mouth, until the moment when the egg sees the light. Then and not till then does it rise.

Guided by the rather less complex structure of the eggs of the other Clythræ and of the Cryptocephali, I think of trying to take the strange germ to pieces; and I succeed after a fashion. Under the coffee-coloured sheath, which forms a little five-hooped barrel, is a white membrane. This is what we see through the mouth and what I compared with the skin of a drum. I recognize it as the regulation tunic, the usual envelope of any insect's egg. The rest, the little brown barrel, broached at one end and bearing a raised lid, must therefore be an accessory integument, a sort of exceptional shell, of which I do not as yet know any other example.

The Long-legged Clythra and the Four-spotted Clythra know nothing of packing their eggs in long-stemmed bundles. In June, from the height of the branches in which they are grazing, both of them carelessly allow their eggs to drop to the ground, one by one, here and there, at random and at long intervals, without giving the least thought to their installation. They might be little grains of excrement, unworthy of interest and ejected at hazard. The egg-factory and the dung-factory scatter their products with the same indifference.

Nevertheless, let us bring the lens to bear upon the minute particle so contumeliously treated. It is a miracle of elegance. In both species of Clythræ the eggs have the form of truncated ellipsoids, measuring about a millimetre in length.2 The Long-legged Clythra's are a very dark brown and remind one of a thimble, a comparison which is the more exact inasmuch as they are dented with quadrangular pits, arranged in spiral series which cross one another with exquisite precision.

2 .039 inch.—Translator's Note.

Those of the Four-spotted Clythra are pale in colour. They are covered with convex scales, overlapping in diagonal rows, ending in a point at the lower extremity, which is free and more or less askew. This collection of scales has rather the appearance of a hop-cone. Surely a very curious egg, ill-adapted to gliding gently through the narrow passages of the ovaries. I feel sure that it does not bristle in this fashion when it descends the delicate natal sheath; it is near the end of the oviduct that it receives its coat of scales.

In the case of the three Cryptocephali reared in my cages, the eggs are laid later; their season is the end of June and July. As in the Clythræ, there is the same lack of maternal care, the same hap-hazard dropping of the seeds from the centaury-blossoms and the ilex-twigs. The general form of the egg is still that of a truncated ellipsoid. The ornaments vary. In the eggs of the Golden Cryptocephalus and the Ilex Cryptocephalus they consist of eight flattened, wavy ribs, winding corkscrew-wise; in those of the Two-spotted Cryptocephalus they take the form of spiral rows of pits.

What can this envelope be, so remarkable for its elegance, with its spiral mouldings, its thimble-pits and its hop-scales? A few little accidental facts put me on the right track. To begin with, I acquire the certainty that the egg does not descend from the ovaries as I find it on the ground. Its ornamentation, incompatible with a gentle gliding movement, had already told me as much; I now have a clear proof.

Mingled with the normal eggs of both the Golden Cryptocephalus and the Long-legged Clythra, I find others which differ in no respect from the usual run of insects' eggs. The eggs are perfectly smooth, with a soft, pale-yellow shell. As the cage contains no other insects than the Clythra under consideration or the Cryptocephalus, I cannot be mistaken as to the origin of my finds.

Moreover, if any doubts remained, they would be dispelled by the following evidence: in addition to the bare, yellow eggs there are some whose base is set in a tiny brown, pitted cup, obviously the work of either the Two-spotted Cryptocephalus or the Long-legged Clythra, according to the cage, but unfinished work, which half-clothed the egg, as it left the ovaries, and then, when the dress-material ran short, or something went wrong with the machinery, allowed it to cross the outer threshold in the likeness of an acorn fixed in its cup.

Nothing could be prettier than this yellow egg, standing in its artistic egg-cup. Nor could anything tell us more conclusively where the jewel is manufactured. It is in the cloaca, the chamber common to the oviduct and the intestine, that the bird wraps its egg in a calcareous shell, often decorating it with magnificent hues: olive-green for the Nightingale, sky-blue for the Wheatear, soft pink for the Icterine Warbler. It is in the cloaca also that the Clythra and the Cryptocephalus produce the elegant armour of their eggs.

It remains to decide upon the material employed. From its horny appearance there is reason to believe that the little barrel of the Taxicorn Clythra and the scales of the Four-spotted Clythra are the products of a special secretion; and, now that it is too late, I much regret that I neglected to look for the apparatus yielding this secretion in the neighbourhood of the cloaca. As for the thing so prettily wrought by the Long-legged Clythra and the Cryptocephali, let us admit without false shame that it is made of fæcal matter.

The proof is furnished by certain specimens, by no means rare in the Golden Cryptocephalus, in which the customary brown is replaced by an unmistakable green, the sign of a vegetable pulp. In course of time, these green eggs turn brown and become like the others, no doubt by reason of an oxidization which alters the natural qualities of the digestive product still further. The egg, entering the cloaca in a soft and utterly naked state, receives an artistic coat of the intestinal dross, even as the Hen's egg is covered by a shell formed of the chalky secretions.

Materiem superabat opus, nam Mulciber illic

Æquora celerat,

said Ovid, in his description of the Palace of the Sun. The poet had precious metals and gems wherewith to build his imaginary marvel. What has the Clythra wherewith to achieve its ideal jewel? It has the shameful material whose name is banished from decent speech. And which is the Mulciber, the Vulcan, the artist-engraver that engraves the covering of the egg so prettily? It is the terminal sewer. The cloaca rolls the material, flutes it, twists it into spirals, decks it with chains of little pits and makes it up into a scaly suit of armour, showing how nature laughs at our paltry standards of value and how well able she is to convert the sordid into the beautiful.

In the bird, the egg-shell is a temporary defensive cell which at hatching-time is broken and abandoned and is henceforth useless. Made of horny matter or stercoral paste, the shell of the Clythra and the Cryptocephalus is, on the contrary, a permanent refuge, which the insect will never leave so long as it remains a larva. Here the grub is born with a ready-made garment, of rare elegance and an exact fit, a garment which it only has to enlarge, little by little, in the original manner described above. The shell, shaped like a little barrel or thimble, is open in front. There is nothing therefore to break, nothing to cast aside at the moment of hatching, except perhaps the actual envelope of the egg. Directly this membrane is burst, the tiny creature is free, with a handsome carved jacket, a legacy from its mother.

Let us indulge in a crazy dream and imagine young birds which keep the egg-shell intact, save for an opening through which they pass their head, and which, all their lives long, remain clad in this shell, on condition that they themselves enlarge it as they grow. This absurd dream is realized by our grub: it is dressed in the shell of its egg, expanded by degrees as the grub itself grows bigger.

In July all my collection of eggs are hatched, each isolated in a large cup covered with a slip of glass which will moderate the evaporation. What an interesting family! My vermin are swarming amid the miscellaneous vegetable refuse with which I have furnished the premises. They all move along with tiny steps, dragging their shells, which they carry lifted on a slant; they come halfway out and suddenly pop in again; they tumble over if they merely attempt to scale a sprig of moss, pick themselves up again, forge ahead and cast about at random.

Hunger, we can no longer doubt, is the cause of this agitation. What shall I give my famished nurselings? They are vegetarians: there can be no doubt whatever about that; but this is not enough to settle the bill of fare. What would happen under the natural conditions? Rearing the insects in cages, I find the eggs scattered at random on the ground. The mother drops them carelessly, here and there, from the top of the bough where she is refreshing herself by soberly notching some tender leaf. The Taxicorn Clythra fits a long stalk to her eggs and fixes them in clusters on the foliage. While I cannot yet make up my mind, in the absence of direct observation, whether the new-born larva cuts the suspension-thread itself, or whether the thread is broken merely as a result of drying up, sooner or later these eggs are lying on the ground, like the others.

The same thing must happen outside my cages: the eggs of the Clythræ and the Cryptocephali are scattered over the ground beneath the tree or plant on which the adult feeds.

Now what do we find under the shelter of the oak? Turf, dead leaves, more or less pickled by decay, dry twigs cased in lichens, broken stones with cushions of moss and, lastly, mould, the final residue of vegetable matters wrought upon by time. Under the tufts of the centaury on which the Golden Cryptocephalus browses lies a black bed of the miscellaneous refuse of the plant.

I try a little of everything, but nothing answers my expectations very positively. I observe, nevertheless, that a few disdainful mouthfuls are taken, a little bit here, a little bit there, enough to tell me the nature of the first layers which the grub adds to its natal sheath. With the exception of the Taxicorn Clythra, whose egg, with its suspension-stalk, seems to denote rather special habits, I see my several charges begin to prolong their shell with a brown paste, similar in appearance to that with whose manufacture and employment we are already familiar.

Discouraged by a food which does not suit them and perhaps also tried by a season of exceptional drouth, my young potters soon relinquish their task; they die after adding a shallow rim to their pots.

Only the Long-legged Clythra thrives and repays me amply for my troublesome nursing. I provide it with chips of old bark taken from the first tree to hand, the oak, the olive, the fig-tree and many others. I soften them by steeping them for a short time in water. The cork-like crusts, however, are not what my boarders eat. The actual food, the butter on the bread, is on the surface. There is a little here of all that the first beginnings of vegetable life add to old tree-trunks, all that breaks up decrepit age to turn it into perpetual youth.

There are tufts of moss, hardly a twelfth of an inch in height, which were sleeping droughtily under the merciless sun of the dog-days, but which a bath in a glass of water awakens at once. They now display their ring of green leaflets, brightened up and restored to life for a few hours. There are leprous efflorescences, with their white or yellow dust; tiny lichens radiating in ash-grey straps and covered with glaucous, white-edged shields, great round eyes that seem to gaze from the depths of the limbo in which dead matter comes to life again. There are collemas, which, after a shower, become dark and bloated and shake like jellies; sphærias, whose pustules stand out like ebony teats, full of myriads of tiny sacs, each containing eight pretty seeds. A glance through the microscope at the contents of one of these teats, a speck only just visible to the eye, reveals an astounding world: an infinity of procreative wealth in an atom. Ah, what a beautiful thing life is, even on a chip of rotten bark no bigger than a finger-nail! What a garden! What a treasure-house!

This is the best pasture put to the test. My Clythræ graze upon it, gathering in dense herds at the most luxuriant spots. One would take this heap for pinches of some brown, modelled seed or other, the snapdragon's, for instance; but these particular seeds push and sway; if one of them moves the least bit, the shells all clash together. Others wander about, in search of a good place, staggering and tumbling under the weight of the overcoat; they wander at random through that great and spacious world, the bottom of my cup.

Not a fortnight has elapsed before a strip, built up on the rim, has doubled the length of the Long-legged Clythra's shell, in order to maintain the capacity of the earthenware jar in proportion to the size of the grub, which has been growing from day to day. The recent portion, the work of the larva, is very plainly distinguishable from the original shell, the product of the mother; it is smooth over its whole extent, whereas the rest is ornamented with tiny holes arranged in spiral rows.

Planed away inside as it becomes too tight, the jar grows wider and at the same time longer. The dust taken from it, once more kneaded into mortar, is reapplied outside, more or less everywhere, and forms a rubble under which the original beauties end by disappearing. The neatly-pitted masterpiece is swamped by a layer of brown plasterwork; not always entirely, however, even when the structure reaches its final dimensions. If we pass an attentive lens between the two humps at the lower end, we very often see, encrusted in the earthy mass, the remains of the shell of the egg. This is the potter's mark. The arrangement of the spiral ridges, the number and the shape of the pits enable us almost to read the name of the maker, Clythra or Cryptocephalus.

From the very first I could not imagine the worker in ceramic paste designing its own pottery by drafting the first outlines. My doubts were justified. The grubs of the Clythra and the Cryptocephalus possess a maternal legacy in the shape of a shell, a garment which they have only to enlarge. They are born the owners of a layette which becomes the groundwork of their trousseau. They increase it, without, however, imitating its artistic elegance. A more vigorous age discards the laces in which the mother delights to clothe the new-born child.

About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books.

This book is part of the public domain. Jean-Henri Fabre (2009). The Glow-Worm and Other Beetles. Urbana, Illinois: Project Gutenberg. Retrieved October https://www.gutenberg.org/cache/epub/27868/pg27868-images.html

This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at www.gutenberg.org, located at https://www.gutenberg.org/policy/license.html.