474 
ZOOLOGY OF 
Rio Negro and Upper Amazon, all ticketed for my own 
use, have been lost ; and of course in such a question as 
this, the exact determination of species is everything. 
The two beautiful butterflies, Callitliea sa/ppJiira and 
C. Leprieuri, which were originally found, the former 
in Brazil, and the latter in Guiana, have been taken by 
myself on the opposite banks of the Amazon, within a 
few miles of each other, but neither of them on both 
sides of that river. 
Mr. Bates has since discovered another species, named 
after himself, on the south side of the Amazon ; and a 
fourth, distinct from either of them, was found by me 
high up in one of the north-western tributaries of the 
Rio Negro, so that it seems probable that distinct spe- 
cies of this genus inhabit the opposite shores of the 
Amazon. 
The cock of the rock, Eupicola cay ana, is, on the 
other hand, an example of a bird having its range de- 
fined by a geological formation, and by the physical 
• 
character of the country. Its range extends in a curv- 
ing line along the centre of the mountainous district of 
Guiana, across the sources of the Rio Negro and Ori- 
nooko, towards the Andes ; it is thus entirely com- 
prised in the granite formation, and in that part of it 
where there are numerous peaks and rocks, in which the 
birds make their nests. 
Whether it actually reaches the Andes, or occurs in 
the same district with the allied E. Eetuviana, is not 
known, but personal information obtained in the dis- 
tricts it inhabits, shows that it is confined to the narrow 
tract I have mentioned, between 1"^ south and 6° north 
