316 THE COLOUES OF ANIMALS 



of sexual recognition may, and frequently does, fail 

 without injury to the species. 



One of the most fundamental instincts provides 

 for an unfailing recognition between the sexes, in 

 which certainty is ensured by the unanimous witness 

 of all the senses, so that even the closest resemblance 

 between distinct species does not appear to produce 

 any evils of the kind suggested by Mr. Wallace. 



The necessity for Recognition can never explain the 

 aesthetic value of the results produced 



It may also be urged that the beauty of the colours 

 and patterns displayed in courtship can never be 

 explained by this principle. For the purposes of recog- 

 nition, beauty is entirely superfluous and indeed un- 

 desirable ; strongly marked and conspicuous differences 

 are alone necessary. But these, which are so well 

 marked in Warning Colours, are not by any means 

 characteristic of those displayed in courtship. 



If an artist, entirely ignorant of natural history, 

 were asked to arrange all the brightly coloured butter- 

 flies and moths in England in two divisions, the one 

 containing all the beautiful patterns and combinations 

 of colour, the other including the staring, strongly 

 contrasted colours, and crude patterns, we should find 

 that the latter would contain, with hardly an exception, 

 the species in which independent evidence has shown, 

 or is likely to show, the existence of some unpleasant 



