It would appear from these facts either that no bee ever succeeds in stinging its assailant, or else that the latter is proof against the injection of poison. The former seems to me the most probable, since the system of the bee itself has no such immunity. It seems strange that so deadly a weapon should fail thus constantly, at a pinch, and it would be interesting to know if these redoubtable adversaries attack wasps as well as bees. As it is not stated that they do so—as wasps are pointedly omitted from the list made out of their victims—the contrary may, I think, be assumed, and also, as a corollary, that if wasps were attacked they would be able to use their sting, probably with fatal effect. This superior capability is, no doubt, owing to the superior flexibility of a wasp’s abdomen over that of a bee; and if we ask ourselves what is the cause of this—how and for what reason the superiority has been acquired—the answer seems “as ready as a borrower’s cap,” viz. “as a means of self-defence through a process of natural selection.” Nothing could be better adapted to bring this process into play than the very ordeal through which the bee is passing; for if some could only succeed, through superior flexibility, in stinging the flies, they ought to increase at the expense of those unable to do so. As far as it goes, this seems to point to the wasp having gone through a longer course of development than the bee—to its ancestry dating farther back in time; but when we think of the latter’s more elaborate social organisation and the greater perfection of its cells, one feels inclined to reverse this opinion. As no bees possess such powers of twisting about and doubling round their abdomens as do wasps, though some can do so in a very fair degree, it seems probable that the common ancestor of all the species was more thickly built than that of the wasps, or at least that the potential capacity handed down by it of development in this direction was less. But precisely the same argument may be used in regard to the brain of the ancestral wasp, and thus we see that unless we have geological evidence on the subject it is very difficult to say which of two species has the more ancient descent.