The three other Ammophilæ give but one caterpillar to each cell. True—size makes up for this; the game selected is corpulent, plump, amply sufficing the grub’s appetite. For instance, I have taken out of the mandibles of A. holosericea a caterpillar fifteen times her own weight—fifteen times!—an enormous sum if you consider what an expenditure of strength it implies to drag such game by the nape of its neck over the endless difficulties of the ground. No other Hymenopteron tried in the scales with its prey has shown me a like disproportion between spoiler and capture. The almost endless variety of colouring in the provender exhumed from the burrows or recognised in the grasp of the various species also proves that the three have no preference, but seize the first caterpillar met with, provided it be neither too large nor too small, and belongs to the moths. The commonest prey are those gray caterpillars which infest the plant at the junction of a root and stem just below the soil. That which governs the whole history of the Ammophila, and more especially attracted my attention, was the way in which the insect masters its prey and plunges it into the harmless state required for the safety of the larva. The prey, a caterpillar, is very differently organised from the victims which we have hitherto seen sacrificed—Buprestids, Weevils, Grasshoppers, and Ephippigers. It is composed of a series of segments or rings set end to end, the three first bearing the true feet which will be those of the future butterfly; others bear membranous or false feet special to the caterpillar and not represented in the butterfly; others again are without limbs. Each ring has its ganglion, the source of feeling and movement, so that the nerve system comprehends twelve distinct centres well separated from each other, without counting the œsophageal ganglion placed under the skull, and which may be compared to the brain. We are here a long way from the nerve centralisation of the Weevil and Buprestis that lends itself so readily to general paralysis by a single stab; very far too from the thoracic ganglia which the Sphex wounds successively to put a stop to the movements of her crickets. Instead of a single centralised point—instead of three nerve centres—the caterpillar has twelve, separated one from another by the length of a segment and arranged in a ventral chain along the median line of the body. Moreover, as is the rule among lower animals, where the same organ is very often repeated and loses power by diffusion, these various nervous centres are largely independent of each other, each animating its own segment, and are but slightly disturbed by disorder in neighbouring ones. Let one segment lose motion and feeling, yet those uninjured will none the less remain long capable of both. These facts suffice to show the high interest attaching to the murderous proceedings of the Hymenopteron with regard to its prey.