THE COLORATION OF ANIMALS 61 



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birds, possess a colouring which makes it very difficult to distinguish 

 them from their usual surroundings. Our large green grasshopper 

 (Locusta viridissima) lays its eggs in the earth, and they are brown, 

 exactly like the earth which surrounds them. They are enough in 

 themselves to refute the hypothesis that sympathetic colouring has 

 arisen through self -photography, for these eggs lie in total darkness 

 in the ground. Insect-eggs which are laid on the bark of trees are 

 often grey-brown or whitish like it, and the eggs of the humming-bird 

 hawk-moth [Macroglossa stellatarum), which are attached singly to the 

 leaves of the bedstraw, have the same beautiful light-green colour as 

 these leaves, and, in point of fact, green is a predominant colour of 

 the eggs in a very large number of insects. 



But the eggs of many birds, too, exhibit ' sympathetic ' colouring ; 

 thus the curlew (Numenius arquata) has green eggs, which are laid in 

 the grass ; but the red grouse (Lagopus scoticus) lays blackish-brown 

 eggs, exactly of the colour of the surrounding moor-soil ; and it has 

 been observed that they remain uncovered for twelve days, for the 

 hen lays only one egg daily, and does not begin to brood until the 

 whole number of twelve is complete. Herein lies the reason of 

 the colour-adaptation, which the eggs would not have required, if 

 they had always been covered by the brooding bird. 



The eggs of birds are frequently not of one colour only ; those of 

 the Alpine ptarmigan {Lagopus alpinus), for instance, are ochre-yellow 

 with brown and red-brown dots, resembling the nest, which is care- 

 lessly constructed of dry parts of plants. Sometimes this mingling of 

 colours reaches an astonishing degree of resemblance to surroundings, 

 as in the golden plover [Gharadrins pluvialis), whose eggs, like those 

 of the peewit (Vanellus cristatus), are laid among stones and grasses, 

 not in a true nest, but in a flat depression in the sand, and, protected 

 by a motley speckling with streaking of white, yellow, grey and 

 brown, are excellently concealed. Perhaps the eggs of the sandpipers 

 and gulls are even better protected, for their colouring is a mingling 

 of yellow, brown, and grey, which imitates the sand in which they are 

 laid so perfectly, that one may easily tread on them before becoming 

 aware of them. 



But let us now turn from eggs to adult animals. Darwin first 

 pointed out that the fauna of great regions may exhibit one and the 

 same ground-colouring, as is the case in the Arctic zone and in the 

 deserts. The most diverse inhabitants of these regions show quite 

 similar coloration, namely, that which harmonizes with the dominant 

 colour of the region itself. It is not only the persecuted animals, 

 which need protection, that are sympathetically coloured in these 



