208 THE ORIGIN AND DEVELOPMENT 



rest by day in exposed situations, and then cover 

 the hind wings with the front pair, and often the 

 abdomen by both ; in such insects the upper 

 surfaces of the front wings are marked with varie- 

 gated patterns, while the hind wings and the 

 under surfaces of both pairs are usually of a uni- 

 form brown color. Even upon the upper surface 

 of the front wings the tints are usually very 

 sombre, bright colors being exceptional among the 

 moths ; while in the lowest tribes there are many 

 examples of almost uniform drab or brown color- 

 ing throughout. To this last statement, however, 

 many exceptions could be given of insects with 

 front wings pictured with variegated designs of 

 such excessive minuteness that their real beauty 

 can be appreciated only when the surface is mag- 

 nified. So, too, in the large family of Phalaeni- 

 dae, or gometrids, we have moths which often fly 

 by day, and rest with all their wings fully ex- 

 panded ; and here the hind wings are ornamented 

 like the front pair. 



It is, however, only when we come to the but- 

 terflies, the highest Lepidoptera, that we find, as 

 a general rule, all the wings and both surfaces 

 highly ornamented. Even within this group we 

 may see differences corresponding to their relative 

 perfection of structure ; for in the lowest family 

 sombre colors prevail, and in very many instances 

 the under surface is almost uniform in tint ; 



