MIMICRY 207 



Brazil, in 1870, drew attention to the fact that in a 

 given area there was a sort of family resemblance 

 between all the distasteful conspicuous butterflies, 

 although they belonged to different genera and sub- 

 families, The conspicuous colouring of these species, 

 he said, was a warning signal to prospective enemies of 

 their distasteful properties. Further, he said that if a 

 certain arrangement of colours were common to a 

 congeries of distasteful butterflies, it was obvious that 

 all these species would share in a common advantage. 

 It would be easier for the butterfly foes of a given 

 area to associate nauseous properties with one or a few 

 simple patterns than with scores of patterns. Professor 

 Poulton has neatly expressed the difference between 

 these two kinds of mimicry by likening the palatable 

 mimic of Bates's theory to a fraudulent trader who 

 imitates the advertisement of an honest trader, whilst 

 the distasteful mimic of Miiller's theory may be com- 

 pared to an honest trader who enters into combina- 

 tion with other honest traders to exhibit an identical 

 advertisement of the same class of goods. An assem- 

 blage of insects exhibiting a close similarity of colour- 

 ing is now known as a Miillerian association, or better 

 as a convergent group. Latter-day entomologists, more 

 especially Professor E. B. Poulton and Dr. F. A. Dixey, 

 have elaborated the mimetic theory so that its originators 

 would perhaps not recognize it as the offspring of their 

 brains. There is a danger of the theory becoming 

 overweighted with hypothesis, and there is certainly a 

 demand for further observation of facts by highly 

 skilled and unprejudiced field-naturalists. 



It is an unfortunate thing that the vast majority of 

 collectors and field-naturalists are poor philosophers, 



