But the majority do not watch over the hatching or the growth of their larvæ. They are forced therefore to lay up a store of food beforehand. They know this, and are not found wanting. But here they are confronted by a most difficult problem. If the prey carried to the nest is dead, it will quickly putrefy; it cannot possibly keep fresh, as it must, for the weeks and months of the larva’s growth. If it is alive it cannot easily be seized by the larvæ, and will represent a menace or even a deadly danger. The Wasp must discover the secret of producing, in her victims, the immobility of death together with the incorruptibility of life. And the Wasps have discovered this secret, for the prey which they provide for their larvæ remain at their disposal to the end without movement and without deterioration. Do these tiny creatures know intuitively the secrets of asepsis which Pasteur discovered with so much difficulty? Such was the conclusion with which Dufour was forced to content himself. He presumed the existence, in the Hunting Wasps, of a virus which was at once a weapon of the chase and a liquid preservative, for the immolation and conservation of the victims. But even if aseptic a dead insect would shrivel up into a mummy. Now this must not occur, and as a matter of fact the Wasp’s victims remain moist indefinitely, just as if alive. And in reality they are not dead; they are still alive. Fabre has demonstrated this by proving the persistence of the organic functions, and by feeding some of them by hand. In short, it is incontestable that the victims are not put to death but merely deprived of movement, smitten with paralysis. How has this result, more miraculous even than asepsis, been obtained by the insect? By the procedure that the most skilful physiologist would employ. By plunging its sting into the victim’s body, not at random, which might kill it, but at certain definite points, exactly where the invisible nervous ganglia are located which control the various movements. For the rest, the operative method varies according to the species and anatomy of the victim. In his investigation of the paralysers, Dufour was unable to imagine any other weapon of the chase than the mere inoculation of a deadly virus; the Hymenopteron has invented a means of immobilising her victim without killing it, of abolishing its movements without destroying its organic functions, of dissociating the nervous system of the vegetative life from that of the life of reaction; to spare the first while annihilating the second, by the precise adaptation of this delicate surgery to the victim’s anatomy and physiology. Dufour was unable to provide anything better for the larva’s larder than mummified victims, shrivelled and more or less flavourless; the Hymenopteron provided them with living prey, endowed with the strange prerogative of keeping fresh indefinitely without food and without movement, thanks to paralysis, far superior in this connection to asepsis.