SYRUP-SIPHONS IN ACTION 81 



of which the Humming-birds of America are far 

 the best known ; and it is a curious and interesting 

 fact that the Humming-birds and Woodpeckers 

 both have the tongue supported on C-springs, for 

 in both the horns of the " hyoid " bone, which 

 supports the base of the tongue, are immensely 

 long and slender, and curve right over the back of 

 the head. This is, however, only one of the cases 

 in which a common internal character is no more 

 important than a common external one, for there 

 is no reason to suppose from the rest of their 

 structure that the Humming-birds and Wood- 

 peckers are related ; and the tongue itself is quite 

 different in the Humming-birds, for though just 

 as protrusible as the Woodpecker's tongue, it is 

 composed of two horny tubes lying parallel, each 

 side of the tongue curling inward, and the whole 

 forming a suction-pump most efficacious in sucking 

 up honey from flowers. 



Syrup-sucking is only a side-line with the Wood- 

 peckers, but with Humming-birds it is certainly 

 the main business in many cases, though all eat 

 insects more or less, and some, such as the plain- 

 coloured " Hermit " group (Phaethornis and allies) 

 do not visit flowers at all, but feed only on insects, 

 for which they search the trunks of trees and the 

 undersides of leaves, always hovering, however, just 

 as the flower-feeding species do before the flowers. 



That Humming-birds are essentially syrup- 

 drinkers is shown by the fact that they come readily 

 to glasses of artificial syrup put out for them, and 

 6 



