266 NOETH AMERICAN BIRDS. 



angle of mouth down to the juguhim, with nearly the whole pectoral area, 

 unbroken black, leaving the gular region and side of the head pale, but 

 thickly streaked. Wing, 15.00 ; tail, 8.80 ; tarsus, 2.35 ; middle toe, 1.50. 

 These specimens may be said to form about the extremes of the young plu- 

 mage. An Iowa skin (No. 59,052 ; Ricksecker) is like the average of far- 

 western examples. 



The melanistic condition bears to the normal plumage of swainsoni pre- 

 cisely the same relation that the black calurus, Cassin, does to the usual 

 style of the western variety of horealis (horealis var. calurus = montanus, 

 Cassin) ; the variable series, connecting these two extremes, and designated 

 by the name horealis var. calurus, which covers the whole, finds an exact 

 parallel in the present species. 



A specimen from the Platte (5,576, i , August; W. S. Wood) is entirely 

 dark rufous-brown beneath (excepting the lower tail-coverts), with the shafts 

 of the feathers black. 



This species is entirely distinct specifically from the B. vulgaris of Europe. 

 The latter has four, instead of only three, outer primaries deeply emarginated, 

 and is very dissimilar in every stage of plumage. 



Var. oxypterus, Cassin. 

 SHARP-WINGED HAWK. 



(Normal young plumaije.) 



Buteo oxypterus, Cass. P. A. N. S. VII, 1855, 282. — Ib. Birds N. Am. 1858, 30.— 

 Strickl. Orn. Syn. I, 1855, 28. — Coues, P. A. N. S. 1866, 9. —Gray, Hand List, 

 I, 8. — Cooper, Birds Cal. 1870, 480. B atco albicaudatus, "Vieill.," Sclater, P. Z. S. 

 1869, 634, No. 22. 



{Melanistic plumage. ) 



Buteo fuliginosus, Sclater, P. Z. S. Lond. 1858, 356. — Ib. Trans. Z. S., July, 1858, 267, 

 pi. Ixii. — RiDGWAY, P. A. N. S. Dec. 1870, 142. 



Sp. Char. Adult; melanistic jylumage (No. 12,117, Mazatlan, Mexico ; Colonel Abert). 

 Entirely fuliginous-black, darkest on head and back ; no white on forehead. Tail cine- 

 reous-umber, crossed with seven very regular and continuous bands of black, the subter- 

 minal one of which is broadest. Lower tail-coverts, and larger under wing-coverts, with 

 transverse bands of dull white ; lining of the wiug unvaried black ; under surface of pri- 

 maries silvery-white, that portion beyond their emargination black, the whitish portion 

 crossed by distant, very obsolete, transverse bars. Third quill longest; fourth and fifth 

 scarcely shorter, and nearly equal ; second equal to sixth ; first shorter than eiglith. Tail 

 square ; scutellse of the tarsus very faintly defined, or, in fact, scarcely detectable (proba- 

 bly accidental), Wing, 13.00 ; tail, 7.00 ; tarsus, 1.95 ; middle toe, 1.55. 



Young male ; normal plumage (No. 8,550, Fort Fillmore, New Mexico ; Dr. T. C. 

 Henry, U. S. A.). Head, neck, and lower parts, soiled ochraceous-white. Feathers of 

 the head above, and neck laterally and behind, with medial stripes of blackish- brown ; 

 jugulum, breast, sides, flanks, and abdomen, with large rounded spots of blackish-brown ; 

 tibife with transverse bars of the same; lower tail-coverts almost immaculate. A con- 

 spicuous " mustache " of blended dusky streaks, from angle of the mouth across the cheeks, 



