304 THE LOWER AMAZONS. CHAr. VII. 



sancl-bank, from having here observed, for the first 

 time, in ascending the river, one of the handsomest of 

 the many handsome butterflies which are found exclu- 

 sively in the interior parts of the South American 

 continent, namely the Papilio Columbus. It is of a 

 cream-white colour bordered with black, and has a 

 patch of crimson near the commencement of its long 

 slender tails. In the forest, amongst a host of other 

 beautiful and curious insects, I found another species 

 of the same genus, which was new to me, namely, the 

 Papilio Lysander, remarkable for the contrasted colours 

 of its livery — crimson and blue-green spots on a black 

 ground. This conspicuous insect may be cited as 

 affording another illustration of the way in which 

 species so very commonly become modified according 

 to the different localities they inhabit. P. Lysander is 

 found throughout the interior of the Amazons country, 

 from Villa Nova to Peru, and also in Dutch and 

 British Guiana. In the Delta region of the Amazons 

 it is replaced by a form which has been treated as a 

 distinct species, namely, the P. Parsodes of Gray. In 

 French Guiana, however, numerous varieties interme- 

 diate between the two are found, so that Ave are 

 compelled to consider them as local modifications of 

 one and the same species. The difference between the 

 two local forms is of a slight nature, and many natu- 

 ralists on this account alone would consider them to 

 belong to the same species ; but the numerous existing 

 intermediate shades of variation show how many grades 

 are possible between even two local varieties of a 

 species. In fact, the steps of modification are found 



