PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 155 



Falco pterodes, Temm., PI. Col. 1, 18-23, pis. 56 {adult) aud 139 {young). 



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

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

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

 49.— SCHLEG., Mus. P.-B. Buteones, 1^63, 13; Rev. Ace. 1873, 110.— 

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

 of Merida, Venezuela); Nom. Neotr. 1873, 119 (Mexico to Brazil). — 

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

 Tachytnorchh pterocles, Kaup, Stiug. Vog. 1844, 123.— Boxap., Consp. 1, 1850, 

 17. 



Buteo alhkauda, 'LEiiS.,Ti:\\te, 1831,81, pi. 15, fig. 2.— Pucheiiax, Rev. et Mag. 

 Zool. 18.50, 214. 



Buteo tricolor, Hartl., lud. Azara, 1847, 1 {iiec D'Orp..) 



"Buteo erythronoins", Scl., P. Z. S. 1859,389 (Oaxaca) {ncc Kiug). — Salvin «& 

 SCL., Ibis, 1860, 401 (Antioquia, Guatemala.)— Lawr., Ann. Lye. N. Y. 

 IX, 1868, 133 (San Jos6 and San Antouio, Costa Rica). 



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

 {=juvA). 



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

 Valley iu Texas (on the eastern side), Coliaia (west coast), aud the City 

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



Diag7iosis.~Wmg, 14.50-18.00; tail, 7.70-10.50; culmeu, .95-1.05; tar- 

 sus, 3.30-3.70 ; middle toe, 1.55-1.80. Form: Third quill longest; fir.>^t 

 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. $ : Uufous patch on les.ser 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 termiually, and passing 

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

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

 towards the base.| 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 iu 

 which part of the tail-feathers are of one plumage aiul 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 a.sh, growing darker terminally, and passing narrowly into 



* Iris hazel-brown ; cert; greenish ; le t yellow. 



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



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



