We will now give a brief description of the larva, without stopping to enumerate the articulations of the palpi and antennæ, which are wearisome details of no immediate interest. It is a fat grub and has a fine, white skin, with pale slate-coloured reflections proceeding from the digestive organs, which are visible when you hold the creature to the light. Bent into a broken arch or hook, it is not unlike the grub of the Cockchafer, but has a much more ungainly figure, for, on its back, at the sudden bend of the hook, the third, fourth and fifth segments of the abdomen [[94]]swell into an enormous hump, a tumour, a bag so prominent that the skin seems on the point of bursting under the pressure of the contents. This is the animal’s most striking feature: the fact that it carries a knapsack.
The head is small, in proportion to the grub’s size, is slightly convex, bright-red and studded with a few pale bristles. The legs are fairly long and sturdy, ending in a pointed tarsus. The grub does not use them as a means of progression. When taken from its shell and placed upon the table, it struggles in clumsy contortions without succeeding in shifting its position; and the helpless creature betrays its anxiety by repeated discharges of its mortar.
Let us also mention the terminal trowel, that last segment lopped into a slanting disk and rimmed with a fleshy pad. In the centre of this inclined plane is the open stercoraceous slit, which thus, by a very unusual inversion, occupies the upper surface. A huge hump and a trowel: that gives you the insect in two words.
In his Histoire naturelle des coléoptères de France, Mulsant describes the larva of the Sacred Beetle. He tells us with meticulous detail the number and shape of the joints of the palpi and antennæ; he sees the hypopygium[4] and its pointed bristles; he sees a multitude of things in the domain of the microscope; and he does not see the monstrous knapsack that takes up almost half the insect, nor does he see the strange configuration of the last segment. There is not a doubt in my mind that the writer of this minute description has made a mistake: the larva of which he speaks is nothing like that of the Sacred Beetle.
We must not finish the history of the grub without saying a few words about its internal structure. Anatomy [[95]]will show us the works wherein the cement employed in so eccentric a manner is manufactured. The stomach or chylific ventricle is a long, thick cylinder, starting from the creature’s neck after a very short œsophagus. It measures about three times the insect’s length. In its last quarter, it carries a voluminous lateral pocket distended by the food. This is a subsidiary stomach in which the supplies are stored so as to yield their nutritive principles more thoroughly. The chylific ventricle is much too long to lie straight and twists round in front of its appendix, in the form of a large loop occupying the dorsal surface. It is to contain this loop and the side-pocket that the back swells into a hump. The grub’s knapsack is, therefore, a second paunch, an annexe, as it were, of the stomach, which is by itself incapable of holding the voluminous digestive apparatus. Four very fine, very long tubular glands, very much entangled, four Malpighian vessels mark the limits of the chylific ventricle.
Next comes the intestine, which is narrow and cylindrical and rises in front. The intestine is followed by the rectum, which pushes backwards. This last, which is exceptionally large and furnished with stout walls, is wrinkled across, bloated and distended with its contents. There you have the roomy warehouse in which the digestive refuse accumulates; there you have the mighty ejaculator, ever ready to provide cement. [[96]]
[1] Cf. The Life and Love of the Insect, by J. Henri Fabre, translated by Alexander Teixeira de Mattos: chap. xi.—Translator’s Note. [↑]
[2] Cf. The Hunting Wasps, by J. Henri Fabre, translated by Alexander Teixeira de Mattos: chaps, iv. to x.—Translator’s Note. [↑]