4 



KNOWLEDGE & SCIENTIFIC NEWS. 



(Jan.. 1905. 



females showing the gradual growth of the tawny 

 colour, however, is interesting. The colour (which is 

 quite unknown on the wings of the male) makes its 



appearance as a small spot, and may be traced Iriini 

 one specimen to another until it is seen to form a large 

 suffusion in the wing-area. Such specimens go far to 



llffnllmw iMtiKa « 1. 'L'pp«rone like malt-. 



bridge over the gap between the //. muippus male and 

 its perfectly mimetic, tawny females; for these tawny 

 blotched females of TJ. bolina seem to show a definite 

 variation in the direction of the Danaii chrysippus pro- 

 totype. It is conceivable that eventually, through the 



agency of natural selection, this dawning mimetic like- 

 ness may be perfected and established, as it appears to 

 have been in the case of H. vtisippus. 



It is impossible to suggest a reason to account for 

 the different courses of natural selection in the case of 

 species so closely related. The fact remains, however, 

 that whereas the colour specialisation of H. misippus ap- 

 pears to be fairly complete, that of H. bolma is still in 

 an elementary stage. The females of H. mhipptis 

 differ both from the male form and from one another, 

 but always in the direction of some well-protected pro- 

 totype; moreover, there are no intermediate forms. 

 The females of H. bolina, on the other hand, vary from 

 specimens that are almost like the males through an 

 extensive range of closelv connected forms, very few of 

 which approach anv existing warniiiglv-coloured proto- 



Although the mimicking Hypolimiias butterflies are 

 often instanced as cases of true or Batesian mimicry, 

 some authors consider them to be typical of what is 

 known as Miillerian mimicrv, in which both the tvpe 



and the copy arc well-protected insects, deriving en- 

 hinced benefit from their mutual likeness. The theory 

 of convergent mimicry, as suggested by Professor 

 Miillcr, will be described in a subsequent article. But 

 the question as to which section of mimicry the 

 Hypolimnas butterflies rightly belong in no way affects 

 the interest attached to their colour development as de- 

 scribed above. 



.An instance of the manner in which butterflies be- 

 longing to widely distinct families develop a close 

 external likeness one to the other, because of their 

 mimicry of a common distasteful type, is seen in the 

 annexed photographs. The prototype is Amaurh 

 dominicanns from South Africa. This is mimicked by 

 one form of Papilto cciica female, which, it is seen, 

 differs from the male not only in colour and marking, 

 but also in the complete loss of the long " tails " of 

 the hind wings. Then the Nymphaline butterfly, 

 Euralia (JJ ypolimnin) anthcdon, in both sexes, is a very 

 perfect mimic of the Amauris. 



There is also, in Cape Colony, another form of 

 Papilio cenea female, which is a striking mimic of 



