The fore-legs, though well-shaped, are of insignificant dimensions. The tiny creature keeps them tucked away under the front of its body, where they serve to hold in position the morsel at which it is nibbling. The middle pair, on the contrary, are long and powerful and well in evidence. Standing up like two stout crutches, they lend stability to the fat, curved paunch, which has a tendency to capsize. When seen from behind, the grub gives the impression of being the most whimsical creature on earth. It is just a pot-belly mounted on a pair of stilts.
What is the object of this curious organization? One can understand the grotesque hump worn by the grub of the Onthophagus, the sugar-loaf knapsack whose weight is constantly overturning the little creature when it tries to change its position. This hump is a storehouse of cement for the construction of the cabin in which the transformation is to [[258]]take place. But we cannot understand the two withered, misshapen legs of the Geotrupes’ grub, which, one would think, would have been very useful if they had grown into serviceable grappling-irons. The grub shifts its position; it climbs up and down inside its tall column of victuals; it moves about in quest of morsels to suit it. Those two neglected supports would make the climbing easier if they were in good condition.
On the other hand, the grub of the Sacred Beetle, confined in a narrow recess, has hardly any need of locomotion. A simple movement of the hinder-part brings within the reach of its mandibles a fresh layer of the victuals to be consumed. No matter: it is blessed with six sound, well-turned legs. The cripple moves to and fro, the lusty athlete is stationary; the limping grub takes its walks abroad, the nimble one sits still. There is no satisfactory way of explaining this paradox.
In the adult form, the Sacred Beetle and his kinsfolk, the Half-spotted Scarab,[1] the broad-necked Scarab[2] and the Pock-marked [[259]]Scarab[3]—the only three that I know—are likewise atrophied: all of them lack the tarsi of the fore-legs. These four witnesses prove to us that this singular mutilation is common to the whole group.
An absurd system of nomenclature has seen fit, in its blindness, to substitute for the ancient and venerable term of Scarabæus that of Ateuchus, meaning weaponless. The inventor of the name was none too well-inspired: there are plenty of other Dung-beetles that have no horny armour, such as the Gymnopleuri,[4] who are so closely allied to the Scarabæi. Since his intention was to designate the genus by calling attention to a characteristic peculiarity, he should have coined a word meaning, “deprived of tarsi on the fore-legs.” Only the Sacred Beetle and his kinsfolk, in the whole of the insect-world, could rightly bear that name. This never occurred to the nomenclator; this important detail was apparently unknown to him. He saw the grain of sand and did not notice the mountain: a defect not uncommon among the forgers of names.
For what reasons are the Scarabs’ fore-legs [[260]]bereft of that one finger, the five-jointed tarsus, which in itself represents the insect’s hand? Why a stump, a docked limb, instead of a fingered extremity, as is the rule every otherwise? One reply suggests itself which at first seems rather plausible. Those zealous pill-rollers push their load backwards, with their head down and their hinder-part in the air; they support themselves on the tips of their fore-legs. The whole effort of the transportation is brought to bear on the extremities of these two levers, which are in constant contact with the rough ground.
A delicate finger, liable to be sprained under such conditions, would be a hindrance, wherefore the pill-maker decided to do without it. How and when was the mutilation effected? Does it occur nowadays, as a workshop accident, during the actual work? No, for you never see a Scarab furnished with tarsi to his fore-legs, however new he may be at his trade; no, for the nymph, lying perfectly at rest in its shell, has fingerless fore-arms like the adult.
The mutilation dates farther back. Suppose we admit that, in the dim and distant ages, a Scarab, owing to some mishap, lost those two inconvenient and almost superfluous [[261]]fingers. Finding himself all the better for it, he transmitted the fortunate defect to his race by way of an ancestral legacy. Since then, the Scarabs form an exception to the rule that fore-legs have digits like the rest.
This would be an attractive explanation, but there are serious difficulties in the way. We ask ourselves by what curious freak the organism can have elaborated in days long past portions destined to disappear afterwards as too cumbrous. Can the plan of the animal frame be devoid of logic, of foresight? Does it design the structure blindly, at the hazard of conflicting circumstances?
Away with such foolishness! No, the Scarab did not at one time have the tarsi which he lacks to-day; no, he did not lose them as the result of being harnessed upside down when rolling his pill. He is now what he always was. Who says so? Unimpeachable witnesses: the Gymnopleurus and the Sisyphus,[5] themselves enthusiastic pill-rollers. Like the Scarab, they push them backwards, head down; like the Scarab, they support themselves, during their arduous task, on the tips of their fore-legs; and those [[262]]legs, notwithstanding their contact with the rough ground, are as perfectly fingered as the others: they possess the delicate tarsi which the Scarab is denied. Then why should the latter prove an exception to what in the others is the rule? How gladly would I welcome a word from the discerning person who could answer my humble question!