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 be provided 

 for each tribe, after its kind. Now these flying tribes 

 become the prey, according to their respective sizes 

 and habits, of the tyrants (Tyranmnoe), the swal- 

 lows, the water-chats (Fluvicolmce), the tyrant 

 warblers (Dumecola), and the todies ; for the true 

 flycatchers, we must remember, are excluded from 

 the range of the New World, 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 Mtiscicapidce live only upon such as could 

 fly. Now the todies appear especially adapted to fill 

 this office : they are fly-catchers, it is true, but 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 be supported, in some manner, by 

 ascertained facts. We must consequently remain in 

 ignorance why the legs of the todies, although 

 equally feeble with those of the flycatchers, are 



