TROPICAL AMERICA.— SHELLS. 87 
virgin forests of the coast: very few of the genera com- 
prised in this family are known in other countries. 
(122.) Ants are as numerous as inWestern Africa, but 
they all appear to belong to different species. The red 
ants of Brazil are so destructive, and at the same time 
so prolific, that they frequently dispute possession of 
the ground with the husbandman, defy all his skill to 
extirpate their colonies, and fairly compel him to leave 
his fields uncultivated. The Termites, or white ants, are 
principally confined to the woods: they are of different 
species ; some building great nests in trees, while others 
are subterraneous ; but there is no evidence to prove 
them the same as those of Western Africa. Locusts of 
a beautiful green, with wings resembling the leaves of 
plants, are not uncommon; but they never become 
noxious ; nor is there, we believe, any instance upon 
record of their associating in flocks, and devastating the 
country. They are, in fact, all specifically distinct from 
those of the Old World. The dipterous insects are re- 
markably few,—a peculiarity in American entomology, 
for which we know not how to account: but it is sin- 
gular, that spiders, which prey more especially upon 
this order, are still more rare ; we never, in fact, met 
with more than two or three species which spun webs + 
yet of the little Sa/tici, or jumping spiders, which wan- 
der about in quest of their prey, we described, upon the 
spot, more than 100 species. Yet, however deficient 
South America may be in Diptera, there are some be- 
longing to the Aselide, of dimensions far exceeding any 
in the world. Few persons would believe in the exist- 
ence of a real fly measuring full two inches long; yet 
several of these are in our museum. 
(123.) The testaceous Mollusca, or shells, are compara- 
tively very few, particularly on the eastern coasts, yet those 
of Chili and Panama have furnished our cabinets with 
many beautiful species: from the latter is brought the 
lovely Murex regius Sw., the Murex radix L., with 
many others of less note. From Chili and Peru we 
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