the whole community would be, if "a divided duty" claimed their attention.
It is not at all necessary to show that the socialism of insects has advanced along these lines—their greater fertility allowing of a still more remarkable specialisation—in order to make out a case for the possibility, or even likelihood, of its hereafter doing so in the case of some birds. There are insect communities, however, composed of males and fertile females, or of the latter only, that may be compared, without much violence, to those of terns or weaver-birds. There are the mason-bees, for instance—numbers of whom labour side by side, each at making its own nest, in which, perhaps, we see an early state of our more truly social hymenoptera. But in nature many ways constantly lead to the same goal, and what this is, or is likely to be, must depend on the kind of advantages which the general conditions prescribe and make possible. It is difficult in the case of animals, no less than in that of man, to imagine any great social advance except through, or side by side with, subdivision of labour; and for real social labour to be subdivided, it must first be extended, that is to say in common. The separate attention paid by each pair of birds in a community to its own young only is not subdivision of labour in the proper socialistic sense of the term; for this labour is not social, but solitary. It appertains, that is to say, to every solitary-breeding animal, or, if not to both parents, at least to one, so that, at best, we do not get beyond
