NATURAL SCIENCES OF PHILADELPHIA. 145 



variable, but with the tip only slightly developed, and the commissure very 

 regular. Color of the bill greenish, or yellowish, white. 3d or 3d and 4th 

 quills longest; outer four to six sinuated on outer webs ; inner webs of outer 

 four or five sinuated. 



Genus POLYBORUS, Yieillot. 



Nostril in the upper anterior angle of the cere, very small, linear, obliquely 

 vertical, the posterior end being the upper one. Cere very narrow, its anterior 

 outline vertical and straight; commissure nearly straight; bill very high 

 and much compressed. Occipital feathers elongated. 



1. 3d quill longest ; 1st shorter than 7th ; outer webs of 2d to 5th (inclu- 

 sive) emarginated at bases; inner webs of outer four emarginated. 



P. auduboni, Cass., and P. t hunts, Mol.* 



Falco (Hypotriorchis) uichardso.nii. 



Falco [Hypotriorchis) richardsonii, Ridgway. 



Falco msalon. Rich, and Swains., Faun. Bor. Am. ii, pi. 25, 1831. Coues, Prod. 

 Orn. Ariz. Ter. (Pr. A. N. S. Phil.) 1866, p. 6 (in text). 



Hah. Interior region of N. Am., from Arctic America southward, between 

 Rocky Mts. and Mississippi valley, to Texas. 



Adult Male. (Smithsonian No. 5171, Mouth of the Vermilion River, near 

 the Missouri, Oct. 25th, 1856, Lt. G. K. Warren Dr. F. V. Hayden). Upper 

 plumage dull earth brown, each feather grayish umber centrally, and with a 

 conspicuous black shaft line. Head above approaching ashy white anteriorly, 

 the black shaft-streaks being very conspicuous. Secondaries, primary-coverts 

 and primaries margined terminally with dull white ; the primary-coverts with 

 two transverse series of pale ochraceous spots ; primaries with spots of the 

 same, corresponding with those on the inner webs. Upper tail-coverts tipped, 

 and spotted beneath the surface, with white. Tail clear drab, much lighter 

 than the primaries, but growing darker terminally, having basally a slightly 

 ashy cast; crossed with six sharply defined, perfectly continuous bands (the 

 last terminal) of ashy white. Head, frontally, laterally and beneath a col- 

 lar around the nape (interrupting the brown above) and the entire lower 

 parts, white, somewhat ochraceous, this most perceptible on the tibia; cheeks 

 and ear-coverts with sparse, fine hair-like streaks of black ; nuchal collar, 

 jugulum, breast, abdomen, sides and flanks with a medial linear stripe of 

 clear ochre brown on each feather; these stripes broadest on the flanks ; each 

 stripe with a conspicuously black shaft-streak; tibia and lower tail-coverts 

 with fine shaft-streaks of brown, like the broader stripes of the other por- 

 tions. Chin and throat, only, immaculate. Lining of the wing spotted with 

 ochraceous-white and brown, in about equal amount, the former in spots ap- 

 proaching the shaft. Inner webs of primaries with transverse broad bars of 

 pale ochraceous eight on the longest. Wing-formula, 2, 34, 1. Wing, 

 7-70; tail, 5-09; culmen, -50; tarsus, 1-30; middle toe, 1-25; outer, -85; in- 

 ner, -7U ; posterior, -50. 



Adult Female. (58983, Berth oud's Pass, Rocky Mts., Colorado Ter., Dr. F. V. 

 Hayden Jas. Stevenson.) Differing in coloration from the male only m the 

 points of detail. Ground color of the upper parts clear grayish drab, the fea- 

 thers with conspicuously black shafts; all the feathers with pairs of rather 

 indistinct roundel ochraceous spots, these most conspicuous on the wings 

 and scapulars. Secondaries crossed with three bands of deeper, more red- 

 dish ochraceous. Bands of the tail pure white. In other respects exactly 



as in the male. 



Wing formula, 3, 2-4-1. Wing, 9-00; tail, 6-10 ; culmen, -55 j tarsus, 



1-40; middle toe, 1-51. _ . ., ., c , 



' Young Male. (40516, Fort Rice, Dacota, July 20, 1865, Bng.-Gen. Alfred 



* South Am. Analogue of P. auduboni. 



1870.] 



