My suspicions were confirmed by an examination of the caterpillar from the point of view of sensibility. Whereas the small game of the Silky Ammophila and the Silvery Ammophila struggle violently if the needle touches them elsewhere than in the ring stung by the Wasp, the big caterpillars of the Sandy Ammophila and especially of the Hairy Ammophila remain motionless, no matter which segment we prick. With them there are no contortions, no sudden twists of the hinder parts; the steel point produces no sign of a remnant of sensibility beyond a faint quivering of the skin. The power of moving and feeling is therefore almost wholly abolished, as it needs must be if the grub is to feed in safety on this monstrous prey. Before placing it in the burrow, the Wasp has turned it into an inert though still living mass. I have been permitted to watch the Ammophila operating with her scalpel on the sturdy caterpillar, and never did the intuitive science of instinct show me anything more exciting. With a friend—soon, alas, to be snatched from me by death!—I was coming back from the plateau of Les Angles to lay snares for the Sacred Beetle and put his skill to the test, when we caught sight of a Hairy Ammophila very busily employed at the foot of a tuft of thyme. We at once lay down on the ground, close to where she was working. Our presence did not frighten the Wasp; in fact, she came and settled on my sleeve for a moment, decided that her two visitors were harmless, since they did not move, and returned to her tuft of thyme. As an old stager, I knew what that daring familiarity meant: the Wasp’s attention was occupied with a serious business. We would wait and see. The Ammophila scratched the ground at the foot of the plant, at the junction of root and stem, pulled up slender grass rootlets and poked her head under the little clods which she had lifted. She ran hurriedly this way and that around the thyme, inspecting every crevice that could give access to what lay below. She was not digging herself a home but hunting some game hidden underground; this was evident from her behaviour, which resembled that of a Dog trying to dig a Rabbit out of his hole. Presently, excited by what was happening overhead and close-pressed by the Ammophila, a big Grey Worm made up his mind to leave his lair and come up to the light of day. That settled him; the huntress was on the spot at once, gripping him by the skin of his neck and holding tight in spite of his contortions. Perched on the monster’s back, the Wasp bent her abdomen and deliberately, without hurrying, like a surgeon thoroughly acquainted with his patient’s anatomy, drove her lancet into the ventral surface of each of the victim’s segments, from the first to the last. Not a ring was left without receiving a stab; all, whether with legs or without, were dealt with in order, from front to back.