TODUS. 
.151 
for it is to counteract such effects that the bristles 
of the true flycatchers, which are altogether more 
powerful birds, are so strong. In a country like 
tropical America, where insect population is so 
dense and so varied, it is essential to the balance 
of creation that suitable checks should he provided 
for each tribe, after its kind. Now these flying tribes 
become the prey, according to their respective sizes 
and habits, of the tyrants ( Tyranninco ), the swal- 
lows, the water-chats ( Fluticolinw J, the tyrant 
warblers ( Dumecola J, and the todies ; for the true 
flycatchers, we must remember, are excluded from 
the range of the N ew¥ orld, their place being supplied 
by the tyrants. Consider, then, what a multitude of 
minute apterous insects, living among foliage, would 
have no equivalent check upon their increase, did 
all the Mmcicapidce live only upon such as could 
fly. Now the todies appear especially adapted' to fill 
this office : they are fty -catchers, it is true, hut very 
partially so; for they exert the power only upon 
particular occasions, and then very feebly. Nay, it 
may even be questioned, whether, — in accordance 
with what we so often find in typical forms, — the 
genuine todies do not occasionally eat soft fruits. 
When nothing, however, is absolutely known of 
the natural history of a group, it would be carrying 
analogy too far were we to attempt any explanation 
which could not he supported, in some manner, by 
ascertained facts. W e must consequently remain in 
ignorance why the legs of the todies, although 
equally feeble with those of the flycatchers, are 
