468 
ZOOLOGY OF 
estimate that at least five hundred species exist in the 
Rio Negro and its tributary streams. The number in 
the whole valley of the Amazon, it is impossible to esti- 
mate with any approach to accuracy. 
i). Insects. 
To describe the countless tribes of insects that swarm 
in the dense forests of the Amazon, would require vo- 
lumes. In no country in the world is there more va- 
riety and beauty ; nowhere are there species of larger size 
or of more brilliant colours. Here are found the extraordi- 
nary harlequin-beetle, the gigantic Prioni and Bynastes ; 
but these are exceptions to the great mass of the Coleo- 
jjtera, which, though in immense variety, are of small 
size and of little brilliancy of colour, offering a great 
contrast to the generally large- sized and gorgeous species 
of tropical Africa, India, and Australia. In the other 
orders the same rule holds good, except in the Hymeno- 
ptera, which contain many gigantic and handsome species. 
It is in the lovely 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 distinguished from 
every other, by having a most extensive and peculiar 
family, the Heliconiida, of which not a single species 
is found in either Europe, Asia, Africa, nor even North 
America (excepting Mexico). Another family, still more 
extensive, of exquisitely beautiful small butterflies, the 
