18.35.] 279 



Adult 5 White, beneath with a few narrow longitudinal lines of dark brown, 

 most observable on the sides and flanks. Upper parts white, on the head and 

 neck behind with narrow longitudinal lines and stripes of dark brown. Plumage 

 of the back., upper wing coverts, and tertiaries white, with regular transverse 

 bands of ' broion,becomi ng somewhat crescent shaped on the scapulars and rnrnp, and 

 slightly acuminate on the shafts of the feathers. Primaries white, brownish- 

 black at their ends, and with imperfect, confluent, transverse bands of brown. 

 Tail white, with about twelve transverse bands of brown. 



Young. Entire upper plumage brown, with transverse bands of dull white, 

 generally interrupted and imperfect in the middle of the feather. Under parts 

 dull white, with numerous circular and irregular-shaped spots of dark brown, 

 largest on the sides, and disposed to form transverse bands on the tibiae and 

 flanks. Quills dark brown, with transverse bands of white tinged with fulvous 

 on their inner webs; tail dark brown with transverse bands of ashy white. 



Dimensions. Total length (of skin) about 24 inches, wing I6,tail 10 inches. 



Specimens in the collection from Greenland are strictly identical with others 

 in the collection of the Academy which were presented by our distinguished 

 members, Messrs. Thomas B., and Edward Wilson, and carefully ascertainedto 

 be undoubted Iceland specimens by the latter gentleman. 



In the present species the entire upper parts are transversely and nearly regu- 

 larly barred with brown, and the under parts less spotted than in the preceding. 

 The young bird also presents the same character on the upper parts in some de- 

 gree, while the under parts are spotted and transversely striped only, and not 

 with the numerous longitudinal stripes of the young of the preceding. 



These two birds appear to be different species so far as I can judge from the 

 specimens before me, and are so regarded by nearly all modern authors. They 

 are, however, nearly related, and I am not without a suspicion of their identity. 



7. ASTUR ATRICAFILLUS, (Wilson). 



A specimen in Dr. Sftckley's collection from the Columbia river, in Oregon. 

 This is the only western specimen that has ever come under my notice. 



S. Accipiter Cooperii, (Bonaparte). 



Specimens from near San Francisco, Cali/ornia, in Lieut. Trowbridge's collec- 

 tion, and from Yakima river, Washington Territory, in that made by Dr. Cooper. 



9. Accipiter mexicanus, Swainson. 



Excellent specimens of adults and young from New Mexico are in the collec- 

 tion of T. C. Henry, M.D., U. S. Army. 



10. Accipiter fuscus, (Gmelin). 



From Shoalwater Bay, Washington Territory, in Dr. Cooper's collection; 

 and from near San Francisco, California, in a Collection made by Mr. R. D. 

 Cutts. 



11. Buteo borealis, (Gmelin). 



In the comparison of numerous specimens of adults and young from various 

 localities in Western North America, with others obtained in the vicinity of 

 Philadelphia, I have failed to detect any differences not consistent with specific 

 identity. There is in some specimens a greater extent of the brown color on 

 the breast, and a deeper shade of rufous on the abdomen and tibiae, than is usual 

 in eastern specimens, but I have found no character in the western bird that I 

 have not seen at some time in the other. In my Synopsis I have erroneously re- 

 garded this bird as Buteo Swainsonii, which I have reason to suppose, as will 

 appear in my notice of that species in the present paper, has also been done by 

 other writers. 



12. Buteo Bairdii, Hoy, Proc. Acad., Philada., vi. p. 452. 



The only specimen yet obtained in Western America is in the collection made 

 by Mr. Kreutzfeldt, who was attached to the party in charge of Lieut. E. G. 

 Beckwith, U. S. Army. It is very similar to the specimen regarded as the more 

 adult of the two described as above cited, but has the brown spots on the under 

 parts larger, and the tibiae transversely barred with dark brown, and tinged 



