178 TROPICAL NATURE, AND OTHER ESSAYS. 



intensified ; as in many thrushes, finches, and hawks ; 

 and among butterflies in the majority of our British 

 species. In cases where the male is smaller the in- 

 tensification of colour is especially well pronounced ; as 

 in many of the hawks and falcons, and in most but- 

 terflies and moths in which the coloration does not 

 materially differ. In another extensive series we have 

 spots or patches of vivid colour in the male, which are 

 represented in the female by far less brilliant tints or 

 are altogether wanting ; as exemplified in the gold-crest 

 warbler, the green woodpecker, and most of the orange- 

 tip butterflies (Anthocharis). Proceeding with our sur- 

 vey, we find greater and greater differences of colour in 

 the sexes, till we arrive at such extreme cases as some of 

 the pheasants, the chatterers, tanagers, and birds-of- 

 paradise, in which the male is adorned with the most 

 gorgeous and vivid colours, while the female is usually 

 dull brown, or olive green, and often shows no approxi- 

 mation whatever to the varied tints of her partner. 

 Similar phenomena occur among butterflies ; and in 

 both these groups there are also a considerable number 

 of cases in which both sexes are highly coloured in a 

 different way. Thus many woodpeckers have the head 

 in the male red, in the female yellow ; while some 

 parrots have red spots in the male, replaced by blue 

 in the female, as in Psittacula diopthalma. In many 

 South American Papilios, green spots on the male are 

 represented by red on the female ; and in several species 

 of the genus Epicalia, orange bands in the male are 

 replaced by blue in the female, a similar change of 

 colour to that in the small parrot above referred to. For 

 fuller details of the varieties of sexual coloration we 



