The three females, two stabbed under my eyes, remained mine. All the feet were quite paralysed, Whether in its natural position or on its back or side, the creature retains whichever is given it. Constant oscillations of the antennæ, and, at intervals, some pulsations of the stomach and movements of the mouthpieces, are the only sign of life. Motion is destroyed but not feeling, for at the least prick where the skin is thin, the whole body shudders faintly. Perhaps one day physiology will discover in these victims a subject for fine studies on the functions of the nervous system. The Hymenopteron’s sting, incomparably skilful in reaching a given point and inflicting a wound to affect it alone, will replace, with immense advantage, the brutal scalpel of the experimenter, which disembowels where it should lightly touch. Meanwhile, here are the results obtained from the three victims, but from another point of view. Only movement of the feet being destroyed, there being no injury save that to the nerve centres, the source of motion, the creature perishes, not from its wound, but from inanition. The experiment was tried thus: Two uninjured ephippigers found in the fields were imprisoned without food, one in the dark, the other in the light. In four days the latter died of hunger, in five the former. This difference of a day is easily explained. In the light the creature is more eager to recover liberty, and as every movement of the animal machine causes a corresponding expenditure of energy, greater activity used up sooner the reserves of the organisation. With light, more agitation and shorter life; in darkness, less movement and longer life; both insects fasted equally. One of the three stabbed was kept in the dark and foodless. In this case there was not only darkness and want of food, but the serious wounds inflicted by the Sphex, and yet for seventeen days it perpetually moved its antennæ. As long as this kind of pendulum oscillates, the clock of life has not stopped. On the eighteenth day the creature ceased to wave its antennæ and died. Thus the seriously wounded insect lived in the same conditions as the uninjured one four times as long. What seems as if it should be a cause of death is really the cause of life. However paradoxical it may at first appear, this result is perfectly simple. Intact, the creature agitates and spends itself; paralysed, it makes only those feeble, internal movements, inseparable from all organised life, and the waste of substance is in proportion to the amount of action employed. In the first case the animal machine works and spends itself; in the second it is at rest and saves itself up. Nourishment no longer repairing loss, the insect in motion spends in four days its food reserves and dies; the motionless one does not spend them, and lives eighteen. Physiology tells us that life is continual destruction, and the Sphex’s victims are a most elegant demonstration of this fact.