IN DEFENSIVE COLORATION 333 



attacks, and that thus gradually the existing resemblance 

 was reached and is by the same process maintained. 

 The immense difference in numbers explains why it is 

 that this approach appears to have been entirely from 

 the side of the Helicojims, and why the Melinaea was not 

 appreciably affected. 



It is interesting to note that the same relationship 

 obtains between the Heliconinae of the special group which 

 provides the Mtillerian mimics, and their models, whether 

 Ithomiine or Heliconine. In both cases the models exist 

 in immensely greater numbers. It has been argued on 

 p. 332 that the Ithomiine models are not more unpalatable 

 than their Heliconine mimics. There is obviously even 

 less reason for supposing increased unpalatability when 

 the models are themselves Heliconinae, 



b. The Old World. — We find precisely the same 

 phenomena in the Old World. The distasteful much- 

 mimicked Sub-Family, the Danainae, contains in addition 

 to smaller aggregates two main groups, the Danaini and 

 the Euploeini. Although the two are closely related, 

 the last-named make up a homogeneous set of species 

 with a very characteristic appearance, and it is convenient 

 to separate them from the far less uniform Danaini. The 

 Danai7ii range all over the tropics of the Old World, 

 are everywhere mimicked, and everywhere enter into 

 synaposematic combinations within the group itself, and 

 with distasteful groups outside. A very few of them 

 enter the New World, where they are mimicked in North 

 (see p. 274) but apparently not in South America. 

 The Etcploeifii^ on the other hand, are almost absolutely 

 restricted to the Oriental and Australian Regions (includ- 

 ing Southern China, Malaya, and Polynesia). Within 

 that area they are predominant, and abound in species. 

 They are much mimicked, and enter largely into synapo- 

 sematic combinations ; but the colours and patterns 

 are almost invariably those of the Euploeini themselves. 

 The wide difference between the superficial appearance 

 of the Euploeini and that of other Lepidoptera in their 

 area of distribution, together with the uniform colouring 

 and pattern of their abundant species and genera (if. 



