26 ON THE CLASSIFICATION OP BIKDS. 
theMyotherincBjOi which it seems to he the rasorial sub- 
genus, both on account of its size, its crest, and its affi- 
nity to Myophorius : there are two or three species, all 
natives of India. The genus Myothera, on the other 
hand, chiefly restricted to tropical America, and com- 
prises numerous species of a small size, clothed in 
dark colours, but prettily variegated with white: al- 
though distinctly separated from tlie oriental group by 
their abruptly hooked and strongly toothed bill, they 
are yet so intimately allied to the small bush-shrikes 
(ThatnnophUirue), that it is almost impossible to draw 
a distinction between them : to this point, however, 
we shall presently return. Of all the tribes of insects 
which swarm in the tropics the ants are the most nu- 
merous ; they are the universal devastators, and in the 
dry and overgrown forests of the interior the traveller 
can scarcely proceed five paces without treading upon 
their nests. To keep these myriads within due limits, 
a wise Providence has called into existence the ant- 
thrushes {fiy. 1270> given to them this parti- 
cular food. Both are proportionate in their geographic 
range ; for beyond the tropical 
latitudes the ants suddenly 
decrease, and their enemies, 
the Myothera, totally disap- 
pear. As a general distinction 
by which this family may be 
known from the bush-shrikes, 
we may mention the difference 
in the feet — the structure of 
one being adapted for walking, 
while that of the other is more 
suited for perching. The ant- 
thrushes are very locally distributed ; for, although the 
group is tropical, we frequently found that a particular 
species, very common in one forest, was replaced in 
another by a second ; while a third locality in the saraq 
district would present us with still another kind, differ- 
ent from those we had previously found. Cayenne and 
