BATES VERSUS FRITZ MULLER 215 



first, against B as well as y4. A certain number of lives 

 must be sacrificed in the period during which inexperienced 

 enemies are being educated to avoid the appearance which 

 A and B bear in common. If we assume that the in- 

 dividuals of the two species are equally abundant and 

 occur intermixed, it follows that these necessary losses will 

 be shared betw^een them, instead of being contributed 

 by each independently, as would be the case if their 

 colours and patterns were different. Each loses only 

 fifty per cent, of what it would lose but for the 

 resemblance — surely an ample measure of * Reciprocal 

 Advantage '. 



The writer in Punch criticized an illustration of the 

 Mullerian theory, believing it to be an illustration of 

 Batesian mimicry. 



I propose, in conclusion, to draw your attention to one 

 of the oldest and best-known, as well as one of the most 

 beautiful, examples of mimicry — one upon which new 

 light has been thrown by increase of knowledge. The 

 example will serve as an illustration of the reasons which 

 have led to the gradual transference of confidence from 

 the Batesian to the Mullerian theory. 



The Danaine butterfly Limnas chrysippics is, perhaps, 

 the commonest species on the earth, ranging over nearly 

 the whole of the Old World tropics. Its conspicuous 

 colouring and simple pattern are everywhere mimicked ; 

 but especially in Africa. In fact, we may confidently 

 conclude that Africa is the ancestral home of the species, 

 because of the intensity of the effect which has been 

 wrought by it upon the butterfly and moth fauna of this 

 part of the world. ^ One of its mimics accompanies 

 chrysippus in all parts of the range : — Hypolimnas viisippics, 

 a Nymphaline butterfly of powerful flight. The mimetic 

 likeness is, as in so many other species, borne by the 

 female alone, but in this sex it is singularly perfect, and 

 in earlier years it has always been regarded as one 

 of the best-known and commonest illustrations of Bates's 

 theory. But it is far more likely that H. viisippus belongs 

 to a genus which is in some way unpalatable, and that it 

 ^ Proc, Amer, Ass, Adv. Sci., 1897, vol. xlvi, p. 244. 



