132 LOWER AMAZONS—PARA TO OBYDOS.  Cuap. VI. 
America, abounding in individuals everywhere in the shades of its 
luxuriant forests, and presenting clusters of varieties and closely allied 
species, as well as many distinct, better marked forms. The closely 
allied species and varieties are a great puzzle to classifiers ; in fact, the 
group is one of those wherein great changes seem to be now going on. 


Heliconius Melpomene. 
A conspicuous member of the group is the H. Melpomene of Linnzeus. 
This elegant form is found throughout Guiana, Venezuela, and some 
parts of New Granada. It is very common at Obydos, and reappears 
on the south side of the river in the dry forests behind Santarem, at the 
mouth of the Tapajos. In all other parts of the Amazons valley, east- 

Heliconius Thelxiope. 
ward to Para and westward to Peru, it is entirely absent. This absence 
at first appeared to me very strange; for the local conditions of these 
regions did not appear so strongly contrasted as to check, in this abrupt 
manner, the range of so prolific a species ; especially as at Obydos and 
Santarem it occurred in moist woods close to the edge of the river. 
Another and nearly allied species, however, takes its place in the forest 
plains: namely, the H. Thelxiope of Hiibner. It is ot the same size 
