12 



U. S. P, R. R. EXP. AND SURVEYS — ZOOLOGY — GENERAL REPORT. 



Sub-Genus Gennaia. 

 FALCO POLYAGRUS, Gas sin. 



Falco polyagria, Cassin, B. of Cal. and Texas, I, p. 88. (1853.) 

 Figures. — Cassln, B. of Cal. and Texas, I, pi. 16. 



Narrow frontal band, line over the eye and entire under parts white ; stripe from the corner of the mouth running 

 downwards, dark brown ; breast and abdomen with longitudinal stripes and spots of brown, which color forms a large and 

 •Conspicuous spot on the flank. Upper parts brown, paler on the rump ; tail above pale grayish brown, narrowly tipped 

 with white, and with transverse bands of white ; quills dark greyish brown ; edge of wing at the shoulder and below 

 white, spotted with brown. Bill bluish ; under mandible yellow at base ; space around the eye bare, with a narrow edging 

 of brown on the first phimage arotmd it, the brown of the bank extending somewhat on to the breast at the wing. 



Younger. Frontal band nearly obsolete ; upper parts uniform pale brown, with narrow rufous stripes on the head ; under 

 arts white, tinged with dull yellow, nearly every feather having a longitudinal stripe of dark brown ; large spaces on the 

 flanks brown ; tarsi and toes lead colored. 



Total length 18 to 20 inches, wing 13 to U, tail 7i to 8 inches. 



Hab. Western Nortli America. Spec, in Nat. Mus. Washington, and Mus. Acad. Philadelphia. 



This is exclusively a species of Western North America, but extending its range east of the 

 Rocky mountains, several specimens having been obtained during the exploration of the upper 

 Missouri and Yellow Stone rivers by the party commanded by Lieutenant G. K. Warren, 

 United States army. A specimen of this species has, also, been recently procured in western 

 Illinois by Mr. J. D. Sergeant, of Philadelphia. 



Adults of both sexes are very similar, in fact not differing except in size, and are almost pre. 

 cisely as described and figured by us as above. 



It is possible that tliis may be thespecices described as Falco mexicanua in. 1850 by Schlegel, 

 but I have been unable to make a reference to his article. 



List of specimens. 



