Now Darwin fully acknowledged the difficulty of attributing these results to the unaided influence of natural selection; but the fact of neuter insects being unable to propagate seemed to him to leave no alternative. And so it seems to Weismann, who accordingly quotes these instincts in support of his views. And so it seemed to me, until my work on _Animal Intelligence_ was translated into French, and an able Preface was supplied to that translation by M. Perrier. In this Preface it is argued that we are not necessarily obliged to exclude the possibility of Lamarckian principles having operated in the original formation of these instincts. On the contrary, if such principles ever operate at all, Perrier shows that here we have a case where it is virtually certain that they must have operated. For although neuter insects are now unable to propagate, their organization indicates--if it does not actually prove--that they are descended from working insects which were able to propagate. Thus, in all probability, what we now call a "hive" was originally a society of sexually mature insects, all presenting the same instincts, both as to propagation and to co-operation. When these instincts, thus common to all individuals composing the hive, had been highly perfected, it became of advantage in the struggle for existence (between different hives or communities) that the functions of reproduction should devolve more upon some individuals, while those of co-operation should devolve more upon others. Consequently, this division of labour began, and gradually became complete, as we now find it in bees and ants. Perrier sustains the hypothesis thus briefly sketched by pointing to certain species of social hymenoptera where we may actually observe different stages of the process--from cases where all the females of the hive are at the same time workers and breeders, up to the cases where the severance between these functions has become complete. Therefore, it seems to me, it is no longer necessary to suppose that in these latter cases all the instincts of the (now) barren females can only have been due to the unaided influence of natural selection.