4 Colouration in Animals and Plants. 



5. Warning Colours, or distinctive markings and tints rendering 

 an animal conspicuous, and, as it were, proclaiming noli me tangere 

 to its would-be attackers. 



6. Sexual Colours, or particular modifications of colour in the two 

 sexes, generally" taking the form of brilliancy in the male, as in the 

 peacock and birds of paradise. 



Under one or other of these headings most schemes of coloura- 

 tion will be found to arrange themselves. 



At the outset, and confining ourselves to the animal kingdom 

 for the present, bearing in mind the fierce intensity of the struggle 

 for life, it would seem that any scheme of colour that would enable 

 its possessor to elude its foes or conceal itself from its prey, would 

 be of vital importance. Hence we might infer that protective 

 colouring would be a very usual phenomenon ; and such we find to 

 be the case. In the sea we have innumerable instances of protec- 

 tive colouring. Fishes that lie upon the sandy bottom are sand- 

 coloured, like soles and plaice, in other orders we find the same 

 hues in shrimps and crabs, and a common species on our shores 

 (Carcinus mamas) has, just behind the eyes, a little light irregular 

 patch, so like the shell fragments around that when it hides in the 

 sand, with eyes and light spot alone showing, it is impossible to 

 distinguish it. 



The land teems with protective colours. The sombre tints of so 

 many insects, birds and animals are cases in point, as are the 

 golden coat of the spider that lurks in the buttercup, and the green 

 mottlings of the underwings of the orange-tip butterfly. Where 

 absolute hiding is impossible, as on the African desert, we 

 find every bird and insect, without exception, assimilating the 

 colour of the sand. 



But if j3rotective colour is thus abundant, it is no less true that 

 colour of the most vivid description has arisen for the sole purpose 

 of attracting notice. We observe this in the hues of many butter- 

 flies, in the gem-like humming birds, in sun-birds, birds of paradise, 

 peacocks and pheasants. To see the shining metallic blue of a 

 Brazilian Morpho flashing in the sun, as it lazily floats along the 

 forest glades, is to be sure that in such cases the object of the insect 

 is to attract notice. 



These brilliant hues, when studied, appear to fall into two 

 classes, having very diverse functions, namely Sexual and Warning 

 Colours. 



