One last remark. We know how furiously Hymenoptera armed with a sting used only for defence rush at the bold man who disturbs their nest, and punish his temerity. Those on the contrary whose sting is used only for hunting are very pacific, as if they guessed how important for their family is the little poison drop in their vase. That droplet is the safeguard of their race—I might really say their means of subsistence; therefore they use it economically, in the serious business of the chase, with no parade of vengeful courage. I was not once punished by a sting when I established myself amid colonies of our various predatory Hymenoptera, whose nests I overturned, carrying off larvæ and provisions. To induce the creature to use its weapon, one must lay hold of it, and even then the skin is not always pierced, unless one puts within reach a part more delicate than the fingers, such as the wrist. VIII LARVA AND NYMPH The egg of Sphex flavipennis is white, elongated, and cylindrical, slightly curved, and measuring three to four millimetres in length. Instead of being laid fortuitously on any part of the victim, it is invariably placed on one spot, across the cricket’s breast—a little on one side, between the first and second pairs of feet. The eggs of the white bordered, and of the Languedocian Sphex occupy a like position—the first on the breast of a cricket, the second on that of an ephippiger. This chosen spot must possess some highly important peculiarity for the security of the young larva, as I have never known it vary. Hatching takes place at the end of two or three days. A most delicate covering splits, and one sees a feeble maggot, transparent as crystal, somewhat attenuated and even compressed in front, slightly swelled out behind, and adorned on either side by a narrow white band formed by the chief trachea. The feeble creature occupies the same position as the egg; its head is, as it were, engrafted on the same spot where the front end of the egg was fixed, and the remainder of its body rests on the victim without adhering to it. Its transparency allows us readily to perceive rapid fluctuations within its body, undulations following one another with mathematical regularity, and which, beginning in the middle of the body, are impelled, some forward and some backward. These are due to the digestive canal, which imbibes long draughts of the juices drawn from the sides of the victim.