438 CLASS AVES. 



Three-toed Jacamar. (Alcyon Tridactyla.) Vail. 

 Jac. Sup. f. L. Lath. Sup. 50, and Spix. 57—2. 



Black-green, above ; reddish-white, beneath ; vent, 

 black. Brazil. 



The Woodpeckers. (Picus.* Lin.) 



Are well defined by their long bill, straight, angular, 

 compressed in a corner at the extremity, and fitted 

 for cleaving the bark of trees ; by their slim tongue, 

 armed towards the end with spears, inclining back- 

 wards, which, thrust forward by the long elastic 

 horns of the os-hyoide, can reach out much beyond 

 the bill ; and by their tail, composed of tent quills, 

 with the stems stiff and elastic, which sustains them 

 by its support when they climb along the trunks of 

 trees. These birds are eminent climbers ; they sup- 

 port themselves in all directions on the bark of trees, 

 which they strike with their bills, and in the clefts 

 and holes of which they drive their long tongue 

 in search of the larvae of insects, on which they 

 feed. Their tongue, independently of its bristles, 

 is supplied with a viscous liquor, furnished by the 

 large salivary glands ; it is withdrawn by two mus- 

 cles, rolled like ribbons round the trachea. In this 

 retractile state the horns of the os-hyoide mount 

 under the skin, and round the head, unto the upper 

 base of the bill ; and the sheath of the tongue is 



* Picus is the name of this bird in Latin. 



f There are properly twelve: but those on the side are extremely 

 small. 



