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NORTH AMERICAN BIRDS. 



Genus POLYBORUS, Vieillot. 



Polyborus, Vieill. 1816. (Type, Falco brasiliensis, Gmelin. P. tharus, Molina.) 

 Caracara, Cuvier, 1817. (Same type.) 



Gen. Char. General aspect somewhat vulturine, but bearing and manners almost gallina- 

 ceous. Neck and legs very long. Bill very high and much compressed, the commissure 

 very straight and regular, and nearly parallel with the superior outline ; cere very narrow, 

 its anterior outline vertical and straight. Nostril very small, linear, obliquely vertical, its 

 upper end being the posterior one ; situated in the upper anterior corner of the cere. 

 Lateral and under portions of the head naked and scantily haired, the skin bright-colored 



NAT. SIZE 



37871,^. 



Wing and tail. 



Polyborus auduhoni. 



(reddish or yellow in life). Occipital feathers elongated. Wings and tail long, the latter 

 rounded ; five outer quills with inner Avebs sinuated ; tliird to the foin-th longest ; first 

 shorter than the sixth, sometimes shorter than the seventh. Feet almost gallinaceous, 

 the tarsus nearly twice as long as the middle toe, but stout ; outer toe longer than the 

 inner; posterior toe much the shortest; claws long, but slender, weakly curved, and 

 obtuse. Tarsus with a frontal series of large transverse scutelte, the lower fourth to 

 , sixth forming a single row, the others disposed in two parallel series of alternating plates; 

 the other parts covered by smaller hexagonal scales. 



This well-marked genus contains but a single species, the P. tharus, Mol., 

 ■which extends its range over the wliole of. tropical and subtropical America, 



