The males of this form are everywhere _almost_ the same in colour and in form of wings, save for a few variations in the sparse black markings on the pale yellow ground. But the females occur in several quite different forms and colourings, and one of these only, the Abyssinian form, is like the male, while the other three or four are _mimetic_, that is to say, they copy a butterfly of quite a different family the Danaids, which are among the _immune_ forms. In each region the females have thus copied two or three different immune species. There is much that is interesting to be said in regard to these species, but it would be out of keeping with the general tenor of this paper to give details of this very complicated case of polymorphism in _P. Dardanus_. Anyone who is interested in the matter will find a full and exact statement of the case in as far as we know it, in Poulton's _Essays on Evolution_ (pp. 373-375[49]). I need only add that three different mimetic female forms have been reared from the eggs of a single female in South Africa. The resemblance of the forms to their immune models goes so far that even the details of the _local_ forms of the models are copied by the mimetic species. It remains to be said that in Madagascar a butterfly, _Papilio meriones_, occurs, of which both sexes are very similar in form and markings to the non-mimetic male of _P. dardanus_, so that it probably represents the ancestor of this latter species. In face of such facts as these every attempt at another explanation must fail. Similarly all the other details of the case fulfil the preliminary postulates of selection, and leave no room for any other interpretation. That the males do not take on the protective colouring is easily explained, because they are in general more numerous, and the females are more important for the preservation of the species, and must also live longer in order to deposit their eggs. We find the same state of things in many other species, and in one case (_Elymnias undularis_) in which the male is also mimetically coloured, it copies quite a differently coloured immune species from the model followed by the female. This is quite intelligible when we consider that if there were _too many_ false immune types, the birds would soon discover that there were palatable individuals among those with unpalatable warning colours. Hence the imitation of different immune species by _Papilio dardanus_!