OF LIFE IN GENERAL. 317 



in the adjacent islands they are more brilliant." By 

 actual measurement, Wallace found that " no less than 

 fourteen Papilionidse inhabiting Celebes and the Moluc- 

 cas are from one-third to one-half greater in extent of 

 wing than the allied species representing them in Java, 

 Sumatra, and Borneo. Six species inhabiting Amboyna 

 are larger than the closely allied forms of the northern 

 Moluccas and New Guinea by about pne-sixth. These 

 include almost every case in which closely allied species 

 can be compared." There are equally distinct local 

 variations of form and colour. For instance, almost 

 every Papilio inhabiting Celebes has wings of a pe- 

 culiar shape, which distinguish it from the allied species 

 of every other island. Thus the upper wings are more 

 elongate and falcate, and the anterior margin is much 

 more curved. 



A remarkable instance of the direct effects of food, 

 or perhaps of conditions of life in general, is mentioned 

 by Darwin, who was himself informed of it by Moritz 

 Wagner. " A number of pupae were brought in 1870 

 to Switzerland from Texas of a species of Saturnia 

 widely different from European species. In May, 1871, 

 the moths developed out of the cocoons, and resembled 

 entirely the Texan species. Their young were fed on 

 leaves of Juglans regia (the Texan form feeding on 

 Juglans nigra), and they changed into moths so differ- 

 ent, not only in colour, but also in form, from their 

 parents, that they were reckoned by entomologists as a 

 distinct species." * -* 



Reference has already been made in a previous chap- 



* Quoted from Beddard's " Animal Colouration," p. 51. 



