I declare moreover, that, to provoke lightning paralysis, the poison, if it is not deposited inside the mass of nervous substance, must act from somewhere very near. This assertion is merely echoing what the Two-banded Scolia has just shown us: her Cetonia-grub, stung less than a millimetre from the regular spot, did not become motionless until next day. There is no doubt, judging by this instance, that the effect of the virus spreads in all directions within a radius of some extent; but this diffusion is not enough for the operator, who requires for her egg, which is soon to be laid, absolute safety from the very first. On the other hand, the actions of the paralysers argue a precise search for the ganglia, at all events for the first thoracic ganglion, the most important of all. The Hairy Ammophila, among others, affords us an excellent example of this method. Her three thrusts in the caterpillar's thorax and especially the last, between the first and second pair of legs, are more prolonged than the stabs distributed among the abdominal ganglia. Everything justifies us in believing that, for these decisive inoculations, the sting seeks out the corresponding ganglion and acts only when it finds it under its point. On the abdomen this peculiar insistence ceases; the sting passes swiftly from one segment to another. For these segments, which are less dangerous, the Ammophila perhaps relies on the diffusion of her venom; in any case, the injections, though hastily administered, do not diverge from a close vicinity of the ganglia, for their field of action is very limited, as is proved by the number of inoculations necessary to induce complete torpor, or, more simply, by the following example. A Grey Worm which had just received its first sting on the third thoracic segment repulses the Ammophila and with a jerk hurls her to a distance. I profit by the occasion and take hold of the grub. The legs of this third segment only are paralysed; the others retain their usual mobility. However helpless in the two injured legs, the animal can walk very well; it buries itself in the earth, returning to the surface at night to gnaw the stump of lettuce with which I have served it. For a fortnight my paralytic retains perfect liberty of action, except in the segment operated on; then it dies, not of its wound but accidentally. All this time the effect of the poison has not spread beyond the inoculated segment.