FALCOXID.E — THE FALCONS. 273 



the wing-fornmla cannot be ascertained. Winy, 15.50; tail, 8.50; tarsii-s, 2.50 ; middle 

 toe, l.(iO. Length, I'Ji ; extent, 47^. 



Young male (52,7(i.'3, Mazatlan, Mox. ; Colonel A. J. Grayson). Generally similar to 

 the preceding ; feathers of neck, back, and under parts more conspicuously spotted with 

 ■white beneath the s\n-face, these spots considerably exposed on the breast and upper tail- 

 coverts. Tail deep dark vandyke-brown, faintly tipped with paler, and cro.s.sod with 

 numerous narrow oblique bands of black; subtcrminal one broadest, being about three 

 fourths of an inch in width; the next one is not a fourth as wide, and crosses about an 

 inch anterior to the last ; the distance between the black banils diminishes towards the 

 base of the tail, so that after the seventh of these, no more can be distinguished. Inner 

 webs passing into whitish towards edges, this prevailing on lateral feathers. Fourth quill 

 longest; third scarcely shorter; fifth but little .shorter than third; second intermediate 

 between fifth and sixth ; first equal to eighth. Wing, 15.30 ; tail, 8.80 ; tarsus, 2.40 ; 

 middle toe, 1.60. Length, loj; alar extent, 48. Bill black at tip, bluish-brown at base ; 

 iris dark brown. 



Hab. Guatemala, Mexico, and adjoining parts of United States ; Arizona (CofEs) ; 

 Santa Clara Co., Cal. (Cooper). 



LIST OF SPECIMENS EX.\MIXED. 



National iluseum, 2 ; Philadelphia Academy, 2. Total. 4. 



There can be but little doubt tliat this ijluma^e denotes a younger stage 

 of the same sjiecies as the £. zonoccrcus of Sclater. The adult Ijird described 

 above is ntoultiug, and two tail-feathers of the old plumage, which have 

 not yet been cast, are precisely like those of this specimen, the new ones l^eing 

 entirely different, as will be seen by the description. Taking with this the 

 exact similarity of the pattern of under side of primaries, as well as the 

 plumage in general, and the sameness of proportions, one cannot l)ut be con- 

 vinced of their identity. The localities of the two .specimens are also so 

 near tliat it is scarcely possible they are distinct. 



The plumage of this stage is parallel, in its relation to the adult, with 

 that of the yoitng of B. albi/roriH var. miniitus, both differing from the mature 

 stage in nearly the same particulars, the more inimerous bands on the tail 

 distinguishing the young of nearly all Butcos from adidts of the same 

 specis. 



An adult specimen from Mexico, in the collection of the Pliiladelijhia 

 Academy (without number or other indications on the label), though resem- 

 bling the two specimens described, in all essential points, differs from them 

 in regard to the coloration of the tail. The main differences are as follows : 

 Tail deep black liasally and subterminally, the tip (very narrowly) and a 

 middle zone about 2.()(t inches broad, and 1.80 from the tip, being duller 

 and more brownish-black, this irregularly defined anteriorly, but of sharp 

 regular definition ahmg the posterior liorder; tlie subterminal black band 

 is very precisely defined on the inner webs, and anterior to this nearly the 

 whole inner web is white, irregularly blotched witli Ijlack towards tlie base, 

 however ; the markings of somewhat longitudinal direction ; tlie outer webs 

 are black to the very base. Wing, 16.50 ; tail, 9.00 ; tarsus, 2.70 ; middle 

 toe, 1.80. Wing-formula, 4, 3 - .5 -2 - 6 - 7, 1. 



VOL. IIL ."^S 



