DIVERGENCE AND ADAPTATION 363 



shapes and endowed them with most curious habits of 

 life. 



We shall consider in this chapter a few of the many 

 adaptations which Nature has produced in order to equip 

 her children for the great battle of life. Many animals 

 are colored in such a way that they are difficult to detect 

 in their natural environment. The fauna of the arctic 

 regions contains a very large proportion of birds and mam- 

 mals which are colored white like the snow and ice among 

 which they live. Animals which live in deserts are very 

 frequently colored much like the sand. A great many 



FIG. 245. A leaf insect. 



leaf-eating insects and larvae are green, while species that 

 are found upon the bark are more commonly of a duller 

 hue. The celebrated leaf insect of South America has 

 wings which simulate not only the shape and color but 

 also the venation of leaves. One of the most striking 

 cases of protective coloration is afforded by the Kallima 

 butterfly which, when it is at rest on a twig with its wings 

 folded together, closely resembles a dead leaf, the tail 

 of its wing corresponding to the stem of the leaf, and a 

 dark line extending across the wings presenting a close 

 likeness to the midrib. Only the under side of the wings 



