PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 155 



Fdlco pterocles, Temm., PI. Col. 1, 1823, pis. 56 (adult) and 139 (young). 



Buteo pterocles, Less., Man. 1, 1828, 103.— Gray, Gen. B. I, 1849, 12 : Hand- 

 list, I, 1869, 8.— Caban., in Schomb. Guiana, III, 1848, 739.— Kaup, 

 Contr. Orn. 1850, 75 (subgeD. Tachyiriorchis). — Burm., Th. Bras. II, 1855, 

 49. — Schleg. , Mus. P.-B. Buteones, lt-63, 13; Rev. Acc. 1873, 110.— 

 Pelz., Orn. Bras. 1871,3, 396.— Scl. & Salt. P. Z. S. 1870, 782 (Andes 

 of Merita, Venezuela); Norn. Neotr. 1873, 119 (Mexico to Brazil). — 

 Lawr., Bull. U. S. Nat. Mus. No. 4, 1876, 41 (Tapani, S. Mexico, July).* 



Tachytriorchis pterocles, Kaup, Saug. Vog. 1844, 123.— Bonap., Consp. 1, 1850, 

 17. 



Buteo alUcauda, Less., Traite", 1831,81, pi. 15, fig. 2.— Pucheran, Rev. et Mag. 



Zool. 1850, 214. 

 Buteo tricolor, Hartl., Ind. Azara, 1847, 1 (nec D'Orb.) 



"Buteo erytlxronotus", Scl., P. Z. S. 1859,389 (Oaxaca) (nec King).— Salvin & 

 Scl., Ibis, 1860, 401 (Antioquia, Guatemala.)— Lawr., Ann. Lyc. N. Y. 

 IX, 1868, 133 (San Jose" and San Antonio, Costa Rica). 



u Buteo harlani" (supposed young), Sharpe, Cat. Acc. Brit. Mus. I, 1874, 191 

 (=juv.\). 



Hab. — The whole of Middle America, north to the Lower Rio Grande 

 Valley in Texas (on the eastern side), Colima (west coast), and the City 

 of Mexico (central plateau); Eastern South America as far as Paraguay. 



Diagnosis.— Wing, 14.50-18.00; tail, 7.70-10.50; culmen, .95-1.05 ; tar- 

 sus, 3.30-3.70; middle toe, 1.55-1.80. Form: Third quill lougest; first 

 intermediate between sixth and eighth. Tail even in adult, slightly 

 rounded in young. Color: Adult, tail white (the lateral feathers much 

 tinged with ash), crossed by a broad subterminal band of black ; the 

 white portion crossed by faint lines or narrow bars of plumbeous. Above 

 dark plumbeous ; rump and lower parts pure white ; throat plumbeous- 

 black or bluish-plumbeous. Flanks, rump, and lining of the wing 

 usually faintly barred with ashy, dusky, or rufous. S : Lesser wing- 

 coverts with a restricted patch of rufous on the anterior portion ; longer 

 scapulars strongly tinged with rufous. 9 : Rufous patch on lesser wing- 

 covert region extended over nearly the whole of its area; longer scapu- 

 lars scarcely tinged with rufous. Young: Tail hoary-grayish (the inner 

 webs mostly white), growing gradually darker terminally, and passing 

 narrowly into dull whitish or rufous at tip ; crossed by numerous nar- 

 row and very indistinct bars of darker, these growing gradually obsolete 

 towards the base.f General color brownish-black, the lower parts more 

 or less variegated (most conspicuously on the posterior portions and on 

 middle of the breast) with ochraceous or whitish. 



Remarks. — The identity of specimens of the two plumages described 

 in the diagnosis as "adult" and "young" is proven by specimens in 

 which part of the tail-feathers are of one plumage and part of the other. 

 Such a specimen is in Mr. Lawrence's collection from the City of Mexico. 



The older individuals in the immature dress are colored as follows: — 

 Tail hoary ash, growing darker terminally, and passing narrowly into 



* Iris hazel-brown ; cere greenish ; fe t yellow, 

 t Fide Salvin, Ibis, October, 1874, 314. 



t These bars are sometimes entirely obsolete on the outer webs. 



