Later, and gradually, as I visited more burrows I came to understand my want of success and the obstinate refusal of the Sphex. I always, without exception, found stored a female ephippiger with an abundant and succulent store of eggs inside her. This, it would seem, is the favourite food of the larvæ. In my rush among the vines I had laid hands on one of the other sex. It was a male which I offered to the Sphex! More clear-sighted than I in the great victualling question, she would have nothing to say to my game. “A male! Is that the kind of dinner for my larvæ? And, pray, for whom do you take them?” How sensitive must be these dainty eaters who appreciate the difference between the tender flesh of the female and the comparatively dry body of the male! What a penetrating glance which can distinguish instantly the one sex from the other, though alike in form and colour! The female has an ovipositor to bury her eggs with, and this is almost the only outward difference between her and the male. This difference never escapes the keen-sighted Sphex, and that is why my experiment made her rub her eyes, immensely puzzled by a prey without an ovipositor, which she was perfectly sure had one when it was caught. At such a transformation what must have passed in her little Sphex brain? Now let us follow her when, the burrow being ready, she returns to find her victim, deserted not far from the place of capture, and after the operation which paralysed it. The ephippiger is in a state like that of the cricket slain by S. flavipennis—a certain proof that stings have been darted into the ganglia of the thorax. Nevertheless, many movements continue, but disconnected, though endowed with a certain vigour. Unable to stand, the insect lies on one side or on its back, moving its long antennæ and palpi rapidly, opening and closing its mandibles, and biting as hard as in its normal condition. The abdomen pants fast and deeply; the ovipositor is suddenly brought under the stomach, which it almost touches. The feet move, but languidly and irregularly, the middle ones seemingly more benumbed than the others. If touched with a needle, the whole body starts wildly; efforts are made to rise and walk without success. In short, the creature would be full of life but for the impossibility of locomotion and even of getting on its feet. There is then a paralysis altogether local—paralysis of the feet, or rather partial abolition and ataxy of movement in them. Is this very incomplete inertia caused by some special disposition of the victim’s nervous system, or is it that only a single stab is given, instead of wounding each ganglion of the thorax, as does the huntress of grasshoppers? I cannot say.