238 DARWIN'S LETTERS TO R. TRIMEN 



of Fritz Miiller's earlier suggestion that Mimicry 

 may be due to Sexual Selection (see pp. 127-8). 

 I do not think that the words really bear this 

 interpretation, but even if they do, it is obvious 

 that a suggestion intended to be taken as a joke 

 cannot be looked upon as a serious anticipation ! 

 Inasmuch as Hewitson makes special reference 

 to the three papers of Bates, Wallace and Trimen, 

 it is not inappropriate to quote his criticisms 

 at this point. 



After describing some of the wonderful forms 

 that would now be placed in the African genus 

 Pseudacraea mimetic of the Acraeine genus Pla- 

 nerna from the same localities, Hewitson proceeds 

 to remark : 



'This strange resemblance to each other of distant 

 and very distinct groupes, which forms the romance of 

 natural history, has afforded wonder and delight to every 

 naturalist, and will do so to the end of time, the more 

 so because of its mystery, unless some much better ex- 

 planation is offered than that proposed by Darwin and 

 his followers, because, unluckily for them, it is just those 

 species which superficially bear the closest resemblance 

 to each other that differ most in their fundamental 

 structure.' 



The objection urged by Hewitson is of course 

 the strongest of all reasons in favour of the views 

 he is attacking. Such fundamental differences 

 exclude an interpretation of resemblance based 

 simply on affinity. It is well that this important 

 statement should be proclaimed by an opponent 



