Let us then imagine an academy of entomologists and physiologists, a congress where the question should be discussed by Flourens, Majendies, Claude Bernards. To obtain at once complete immobility and long preservation of food, the first and most natural and simple idea would be that of preserved meats. One would invoke some antiseptic liquid, as the illustrious savant of the Landes did with regard to his Buprestids, and attribute such virtue to the poisonous fluid of the Cerceris, but this strange quality has yet to be proved. Gratuitous hypothesis replacing the unknown quantity of the preserving liquid may perhaps be the final verdict of the learned assembly, as it was that of the naturalist of the Landes. Should one insist and explain that the larvæ require not preserved food which could never have the properties of flesh still palpitating, but prey yet alive, so to say, in spite of complete absence of motion, the learned Congress, after ripe consideration, will fall back upon paralysis: “Yes, of course; the creature has to be paralysed without being killed.” There is but one means of arriving at this result, namely, to injure, cut, and destroy the nervous system of the insect in one or more skilfully chosen points. If the question be thus left in hands unfamiliar with the secrets of a delicate anatomy it will not have advanced far. What is the arrangement of this nervous system which must be paralysed without killing the insect? First, where is it? In the head no doubt and along the back, like the brain and spinal marrow in the superior animals. “A grave mistake!” our congress would reply; the insect is so to say an animal reversed, which walks on its back—that is, it has the spinal marrow below instead of above, all along breast and stomach; therefore on the lower surface alone can the operation to paralyse the insect be performed.