And indeed, if we tear the double envelope which protects this mystery, we recognize, not without astonishment, that we have before our eyes a new larva similar to the secondary. After one of the strangest transformations, the creature has gone back to its second form. To describe the new larva is unnecessary, for it differs from the former in only a few slight details. In both there is the same head, with its various appendages barely outlined; the same vestiges of legs, the same stumps transparent as crystal. The tertiary larva differs from the secondary only by its abdomen, which is less fat, owing to the absolute emptiness of the digestive apparatus; by a double chain of fleshy cushions extending along each side; by the rim of the stigmata, crystalline and slightly projecting, but less so than in the pseudochrysalis; by the ninth pair of breathing-holes, hitherto rudimentary but now almost as large as the rest; lastly by the mandibles ending in a very sharp point. Evicted from its twofold sheath, the tertiary larva makes only very lazy movements of contraction and dilation, without being able to advance, without even being able to maintain its normal position, because of the weakness of its legs. It usually remains motionless, lying on its side, or else displays its drowsy activity merely by feeble, wormlike movements. By dint of these alternate contractions and dilations, indolent though they be, the larva nevertheless contrives to turn right round in the sort of shell with which the pseudochrysalidal integuments provide it, when by accident it finds itself placed head downwards; and this operation is all the more difficult inasmuch as the larva almost exactly fills the cavity of the shell. The creature contracts, bends its head under its belly and slides its front half over its hinder half by wormlike movements so slow that the lens can hardly detect them. In less than a quarter of an hour the larva, at first turned upside down, finds itself again head uppermost. I admire this gymnastic feat, but have some difficulty in understanding it, so small is the space which the larva, when at rest in its cell, leaves unoccupied, compared with that which we should be justified in expecting from the possibility of such a reversal. The larva does not long enjoy the privilege which enables it to resume inside its cell, when this is moved from its original position, the attitude which it prefers, that is to say, with its head up.