46 PROCEEDINGS OF THE ACADEMY OP 



This fine species is radically different from any of the foregoing Buteones, 

 belonging to a group subgenerically distinct, partially characterized by a 

 different amount of feathering of the tarsi. Among North American species 

 it is only intimately related to lineatus, from which species the study of its 

 neossology readily enables us to distinguish it. 



(17.) Bctko zonocercus Sclater. 



B. zonocercus, Sclater, Trans. Zool. Soc. Lond. 1858, p. 263. 



A single specimen, procured on the Gila River, Sept. 24, 1864. The species 

 is doubtless restricted in its northern range to the warm valleys of the Gila 

 and Lower Colorado. 



This interesting Mexican species was first found within the limits of the 

 United States by the indefatigable Cooper, who procured a specimen in Santa 

 Clara County, California. Without being aware of this at the time, I redis- 

 covered it myself in Arizona ; an additional example of what has occurred in 

 several instances in our operations in the West, during the greater part of 

 which each was ignorant of the other's exact whereabouts and labors. I 

 must yield to my friend the priority of discovery, although I have the pleas- 

 ure of first presenting the species in an American publication as an addition 

 to the United States Fauna. 



18. Archibuteo PERR0GINED3 (Licht.) Cassin. 



Buteo ferrugineus, Lichtenstein, Trans. Acad. Berlin, 1838, p. 428. 

 Archibuteo ferrugineus, Cassin, B. N. A. 1858, p. 34. 

 Archibuteo regalia, Gray, Genera, i. pi. vi. (desc. nulla.) 

 Buteo Calif or nicus, A. J. Grayson, Hutchins' Cal. Mag. 1857. 



This large, noble, and by far the handsomest of our Falconines, hitherto 

 only known from California, is found quite abundantly about Fort Whipple, 

 especially in winter. It is probably a permanent resident there. It chiefly fre- 

 quented meadows, plains and more open woods. 1 observed it to be quite numer- 

 ous on the dry, level, grassy plains of Southern California. I usually found the 

 stomach filled with Geomys, Arvicola, or Hesperomys. In life it may always be 

 readily recognized by its conspicuously white under parts, contrasted with its 

 dark chestnut tibiae and reddish back. 



No. 1114, taken Dec. 2, 1864. Male. Length 22-50; extent 54-50; wing 

 16-25; tail 9-50 ; tibia 4-80; tarsus 3-25; middle toe 125; its claw -75; outer 

 toe -85; its claw -55 ; hallux 1-00; its claw 1-00; bill along culmen 1-50; 

 along gape 2-00; its depth at base -90. No. 1115, taken Dec. 6, 1864. Fe- 

 male. Length 23-25 ; extent 56-50 ; wing from carpus 46-75 ; tail 10-00 ; 

 tarsus 3-40 ; the other measurements not differing notably from those of the 

 male above given. 



When perfectly adult, the whole under parts, from chin to under tail cov- 

 erts, inclusive, are pure white. In the majority of specimens, however, there 

 will be found a few slender, sharp, shaft lines of black on the chin; which, 

 as they pass down the breast, become broader, and tinged with chestnut. 

 Usually, also, the feathers of the flanks have small, isolated, interrupted and 

 incomplete bars of chestnutand black. Less mature specimens exhibit a con- 

 tinuation of these bars quite across the lower part of the abdomen, and they 

 are so broadened as to form somewhat hastate spots. Some of the feathers 

 of the flanks are tipped with chestnut. The chief other variations in adult 

 birds seem to be a greater or less intensity of the deep color of the tibiae, a 

 lighter or darker shade of ferrugineous on the back, and a fainter or more de- 

 cided wash of pearl grey on the superior surface of the tail. 



The bill is dark leaden bluish black. The mouth is light purplish flesh 

 color, becoming livid bluish on the corneous portions. The cere, edges of 

 the commissure, tarsi and toes are bright chrome yellow. The claws are 

 black. The naked skin just over the eye is greenish, tinged with crimson 

 posteriorly. The iris of adult birds is fine light yellow ; of young ones 

 brown, more or less ochraceous with increasing age. 



[March, 



