Younger? Upper parts very dark-brown, or nearly black, with purplish lustre. Under parts with almost every feather having a large spot of brownish-black, which color predominates on the breast, so as to present a nearly uniform color with the upper parts; throat with narrow stripes of the same color. Flanks and inferior wing-coverts with circular and oval spots of white. Tibiæ dark-brown, with transverse bars and circular and oval spots of reddish-white. Upper tail-coverts reddish-white, with their outer edges brown, and with transverse stripes of the same. Under tail-coverts yellowish-white, with transverse stripes of brown. Forehead white; cheeks yellowish-white. Stripes from the corners of the mouth wide and conspicuous. Sex unknown. Dimensions. _Female_—total length (of skin), 19½ inches; wing, 15; tail, 8 inches, and about an inch longer than the folded wings. Hab. Wisconsin. Spec. in Mus. Acad. Philada. Obs. This is a well-marked species, especially in the stage of plumage described above as probably the younger, in which the nearly uniformly brownish-black breast and large spots of the same color on the other under-parts, are striking characters. The first-described plumage resembles that of _B. pennsylvanicus_. We have seen only the two specimens now described, both of which are from the State of Wisconsin. 5. Buteo pennsylvanicus. (Wilson.) The Broad-winged Hawk. Falco pennsylvanicus. Wils., Am. Orn., VI. p. 92. (1812.) Falco latissimus. Wils., Am. Orn., VI. p. 92. (1812. Copies printed later than those containing the preceding name.) Sparvius platypterus. Vieill., Ency. Meth., III. p. 1273. (1823.) Falco Wilsonii. Bonap., Jour. Acad. Philada., III. p. 348. (1824.) Wils., Am. Orn., VI. pl. 54, fig. 1; Aud., B. of Am., pl. 91, oct. ed. I. pl. 10; Nat. Hist. N. Y. Orn., pl. 5, fig. 11.