Mimicry 55 



one, which is especially remarkable, and which has been thoroughly 

 investigated, Papilio dardanus (merope), a large, beautiful, diurnal 

 butterfly which ranges from Abyssinia throughout the whole of Africa 

 to the south coast of Cape Colony. 



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- L& " 

 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 poly- 

 morphism 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 *). 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 these 

 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 explana- 

 tion 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 mimeti- 

 cally 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 



1 Professor Poulton has corrected some wrong descriptions which I had unfortunately 

 overlooked in the Plates of my book Vortrage ilber Descendenztheorie, and which refer 

 to Papilio dardanus (merope). These mistakes are of no importance as far as an under- 

 standing of the mimicry-theory is concerned, but I hope shortly to be able to correct 

 thum in a later edition. 



