The Sphex, finding that her prey resists too much, hooking itself here and there to blades of grass, pauses to perform the singular operation about to be described—a kind of coup de grâce. The Hymenopteron, still astride her victim, makes the articulation in the upper part of the neck, at the nape, to open wide. Then she seizes the neck with her mandibles, groping as far forward as possible under the skull, but making no outward wound, grasps and chews repeatedly the nerve-centres of the head. This renders her victim quite motionless, and incapable of the least resistance, whereas previously the feet, though unable to move in the manner necessary for walking, vigorously resisted being dragged along. This is the fact in all its eloquence. While leaving intact the thin, supple membrane of the neck, the insect finds a way into the skull with the point of its mandibles, and bruises the brain. There is neither effusion of blood nor wound, but merely external compression. Of course I kept the paralysed ephippiger under inspection in order to watch the consequences of the operation at my leisure, and equally of course I hastened to repeat on living specimens what the Sphex had taught me. I will now compare my results with hers. Two ephippigers, whose cervical ganglia I compressed with pincers, fell quickly into a state like that of her victims, only they sounded their harsh cymbals if irritated by the point of a needle, and their feet made some irregular languid movements. The difference in the results obtained doubtless arises from the fact that my victim had not been previously stung in the thoracic ganglia, as those had been which the Sphex had struck in the breast. Allowing for this important point, it will be seen that I made no bad pupil, and imitated my teacher in physiology, the Sphex, not ill. I own that it was not without a certain satisfaction that I found I had done almost as well as the insect does.