326 ZOOLOGY OF 



butterflies that the Amazonian forests are unrivalled, whether 

 we consider the endless variety of the species, their large size, 

 or their gorgeous colours. South America is the richest part 

 of the world in this group of insects, and the Amazon seems 

 the richest part of South America. This continent is distin- 

 guished from every other by having a most extensive and 

 peculiar family, the HeliconiidcB, of which not a single species 

 is found in either Europe, Asia, Africa, or even North America 

 (excepting Mexico). Another family, still more extensive, of 

 exquisitely beautiful small butterflies, the Erycinidtz, is also 

 almost peculiar to it, a few species only being found in tropical 

 Asia and Africa. In both these peculiar families the Amazon 

 is particularly rich, so that we may consider it as the head- 

 quarters of South America Lepidoptera. 



Para itself, for variety of species, is perhaps the best locality 

 for diurnal Lepidoptera ; six hundred distinct kinds may be 

 obtained within a day's walk of the city. At Santarem I had 

 increased my collection to seven hundred species, at Barra to 

 eight hundred, and I should have brought home with me nine 

 hundred species had my collections arrived in safety. Mr. 

 Bates, who has paid more exclusive attention to insects, states 

 that he has now obtained twelve hundred species, a wonderful 

 collection to be made by one person, in a country without any 

 variation of climate or of physical features, and no part of it 

 elevated five hundred feet above the level of the sea. 



E. Geographical Distribution of Animals. 



There is no part of natural history more interesting or 

 instructive than the study of the geographical distribution of 

 animals. 



It is well known that countries possessing a climate and soil 

 very similar, may differ almost entirely in their productions. 

 Thus Europe and North America have scarcely an animal in 

 common in the temperate zone ; and South America contrasts 

 equally with the opposite coast of Africa ; while Australia 

 differs almost entirely in its productions from districts under 

 the same parallel of latitude in South Africa and South 

 America. In all these cases there is a wide extent of sea 

 separating the countries, which few animals can pass over; so 



