Ii46 THE ORIGIN OF SPECIES 



changed habits, or exclusively to one of its several hab 

 its. It is, however, difficult to decide, and immaterial 

 for us, whether habits generally change first and struc- 

 ture afterward; or whether slight modifications of struc- 

 ture lead to changed habits; both probably often occur- 

 ring almost simultaneously. Of cases of changed habits 

 it will suffice merely to allude to that of the many Brit- 

 ish insects which now feed on exotic plants, or ex- 

 clusively on artificial substances. Of diversified habits 

 innumerable instances could be given: I have often 

 watched a tyrant flycatcher (Saurophagus sulphuratus) 

 in South America, hovering over one spot and then 

 proceeding to another, like a kestrel, and at other times 

 standing stationary on the margin of water, and then 

 dashing into it like a kingfisher at a fish. In our own 

 country the larger titmouse (Parus major) may be seen 

 climbing branches, almost like a creeper; it sometimes, 

 like a shrike, kills small birds by blows on the head; 

 and I have many times seen and heard it hammering the 

 seeds of the yew on a branch, and thus breaking them 

 like a nuthatch. In North America the black bear waa 

 seen by Hearne swimming for hours with widely open 

 mouth, thus catching, almost like a whale, insects in the 

 water. 



As we sometimes see individuals following habits dif- 

 ferent from those proper to their species and to the other 

 species of the same genus, we might expect that such 

 individuals would occasionally give rise to new species, 

 having anomalous habits, and with their structure either 

 slightly or considerably modified from that of their type. 

 And such instances occur in nature. Can a more strik- 

 ing instance of adaptation be given than that of a wood- 



