Chapter II. 



Physiology of Insects' Eggs.— Their Colour, Structure, Shape, Site, 

 and Number. 



It was a notion of Darwin's (much more ingenious 

 and plan ible than his metamorphoses of shell-fish 

 into birds,) that the variety in the colours of ei>:<;s, 

 as well as the colours of many animals, is adapted to 

 the purposes of concealment from their natural ene- 

 mies. Thus, he says, the snake, the wild cat, and 

 the leopard, are so coloured as to resemble dark 

 leaves and their lighter interstices ; birds resemble 

 the colour of the brown ground or the green hedges 

 which they frequent; while moths and butterflies are 

 coloured like the flowers which they rob of their 

 honey*. By following up this curious theory, Gloger, 

 a German naturalist f, has remarked, that those 

 birds whose eggs are of a bright or conspicuous 

 colour instinctively conceal their nests in the liollows 

 of trees, never quit them except during the night, or 

 sit immediately after they have laid one or two eggs. 

 On the other hand, in the case of birds who build an 

 exposed nest, the colours of the eggs are less at- 

 tractive. Amongst birds w.hose eggs are perfectly 

 white — the most conspicuous of all colours, — he 

 instances the kingfisher (Jlccdo), which builds in 

 a hole in a river's bank; the woodpecker (P/c?/.s), 

 which builds in the hole of a tree; and the swallow 

 {Hirundo domesiica), whose nest has a very small 



* Zoonomia, Sect. 39, p. 248, Srd ed., and Botan. Gardt'n, 

 note on Rubia. 



f Verhuiid. der Gesel'lsch. Natiufurhch. Freunde. Berlin, 

 1824. 



