I find the necessary information in M. Émile Blanchard’s fine work on the nervous system of the Coleoptera. [12] I see there that this centralization of the nervous system is the prerogative, in the first place, of the Scarabæidæ, or Chafers; but most of these are too large: the Cerceris could perhaps neither attack them nor carry them away; besides, many of them live in the midst of ordure where the Wasp, herself so cleanly, would refuse to go in search of them. Motor centres very close together are found also in the Histers, who live on carrion and dung, in an atmosphere of loathsome smells, and who must therefore be eliminated; in the Scolyti, who are too small; and lastly in the Buprestes and the Weevils. What an unexpected light amid the original darkness of the problem! Among the immense number of Beetles whereon the Cerceres might seem able to prey, only two groups, the Weevils and the Buprestes, fulfil the indispensable conditions. They live far removed from stench and filth, two qualities perhaps invincibly repugnant to the dainty huntress; their numerous representatives vary considerably in size, in much the same way as their kidnappers, who can thus pick and choose the victims that suit them; they are far more vulnerable than any of the others at the one point where the Wasp’s dart can penetrate, for at this point the motor centres of the feet and wings are crowded together, all easily accessible to the sting. At this point, in the Weevils, the three thoracic ganglia are very close together, the last two even touching; at the same point, in the Buprestes, the second and third are mingled in one large mass, very near the first. And it is just Buprestes and Weevils that we see hunted, to the absolute exclusion of all other game, by the eight species of Cerceres whose provisions have been found to consist of Beetles! A certain inward resemblance, that is to say, the centralization of the nervous system, must therefore be the reason why the lairs of the different Cerceres are crammed with victims bearing no outward resemblance whatever.