338 



COMPARATIVE ZOOLOGY. 



FIG. 324 White-throated Sparrow (Zonotrichia 

 albicolli*). United States. 



merous and varied in the whole class. It comprehends all 

 those tribes which live habitually among trees, excepting 



the Rapacious and 

 Climbing Birds, and 

 whose toes three 

 in front, and one be- 

 hind are eminently 

 fitted for perching 

 only. The legs are 

 slender, and seldom 

 used for locomo- 

 tion. 



They are divisible 

 into two sections : 



a. ClamatoreSj with 

 nothing in common 

 but a harsh voice. In 

 most, the tarsus is 

 enveloped in a row 

 of plates, which meet 

 behind in a groove, 

 and the bill broad, 

 and bent down ab- 

 ruptly at the tip. 

 The typical repre- 

 sentatives are the 

 Tyrant Fly-catchers. 



b. seines ) or Song- 

 sters, all of whom 

 have a vocal appa- 

 ratus, though not 



FIG. 326. White-eyed Vireo (Vireo Noveboracensui). all Singf. The ail- 

 United States. 



tenor face of the 



tarsus is one continuous plate, or divided transversely 

 into large scales ; and the plates on the sides meet be- 



Fio. 325. Redstart (Setojjhaga ruticilla). United 

 States. 



