22 GERMINAL SELECTION. 



fore wings, but extends to a third or even more of 

 their wings, and these species are also in the habit of 

 drawing back their wings less completely in the state 

 of rest, thus rendering a larger portion of them vis- 

 ible. There are species, too, like the forest-butterflies 

 of South America just mentioned, the Protc^onius, 

 Anaea, Kallima species, etc., which have nearly the 

 whole of the under surfaces of their fore wings 

 marked according to the same pattern with their hind 

 wings, and these butterflies when at rest hold their 

 fore wings free and uncovered by their hind wings. 

 Where are the formative laws in such cases? 



Or, perhaps some one will say: "The covering by 

 the hind wings hinders the formation of scales on the 

 wing, or impedes the formation of the colors in the 

 scales." Such a person should examine one of these 

 species. He will find that the scales are just as dense 

 on the covered as on the uncovered surface of the 

 wing, and in many species, for example, in Katagram- 

 ma, the scales of the covered surface are colored most 

 brilliantly of all. 



But the facts are still more irresistible, when we con- 

 sider special adaptations; for example, the imitation of 

 leaves, which is so often cited. It is to be noted, first, 

 that this sort of imitation is by no means restricted 

 to a few genera, still less to a few species. All the 

 numerous species of the genus Anaea, which are dis- 

 tributed over the forests of tropical South America, 

 exhibit this imitation in pronounced and varied forms, 

 as do likewise the American genera Hypna and Sider- 

 one, the Asiatic Symphaedra, the African Salamis, 

 Eurypheme, etc. I have observed fifty-three genera 

 in which it is present in one, several, or in many 

 species, but there are many others. 



