_Accipiter pennsylvanicus_, VIG. Zoöl. Journ. I, 338.—STEPH. Zoöl. XIII, ii, 32, 1815.—RICH. Faun. Bor.-Am. II, 44, 1831.—JARD. (WILS.) Am. Orn. II, pp. 210, 215, 1832.—SWAINS. Classif. B. II, 215, 1837. _Astur pennsylvanicus_, LESS. Man. Orn. I, 92.—_James._ (_Wils._) Am. Orn. I, 70, 1831. _Nisus pennsylvanicus_, CUV. Règ. An. (ed. 2), I, 334, 1829.—LESS. Tr. Orn. p. 59, 1831. _Falco columbarius_, var., SHAW. Zoöl. VII, 189, 1809. _Accipiter ardosiacus_, VIEILL. Enc. Méth. III, 1274, 1823. _Accipiter fringilloides_ (not of VIGORS!), JARD. (WILS.) Am. Orn. II, 215, 1832. _? Nisus pacificus_, LESSON, Man. et d’Oiseaux, 1847, 177 (Acapulco to California. Square tail). _Accipiter fuscus_, BREWER, Oölogy, 1857, 18, pl. III, f. 23, 29; pl. V, f. 54. SP. CHAR. _Adult male_ (11,990, District of Columbia; A. J. Falls). Above deep plumbeous, this covering head above, nape, back, scapulars, wings, rump, and upper tail-coverts; uniform throughout, scarcely perceptibly darker anteriorly. Primaries and tail somewhat lighter and more brownish; the latter crossed by four sharply defined bands of brownish-black, the last of which is subterminal, and broader than the rest, the first concealed by the upper coverts; tip passing very narrowly (or scarcely perceptibly) into whitish terminally. Occipital feathers snowy-white beneath the surface; entirely concealed, however. Scapulars, also, with concealed very large roundish spots of pure white. Under side of primaries pale slate, becoming white toward bases, crossed by quadrate spots of blackish, of which there are seven (besides the terminal dark space) on the longest. Lores, cheeks, ear-coverts, chin, throat, and lower parts in general, pure white; chin, throat, and cheeks with fine, rather sparse, blackish shaft-streaks; ear-coverts with a pale rufous wash. Jugulum, breast, abdomen, sides, flanks, and tibiæ with numerous transverse broad bars of delicate vinaceous-rufous, the bars medially somewhat transversely cordate, and rather narrower than the white bars; laterally, the pinkish-rufous prevails, the bars being connected broadly along the shafts; tibiæ with rufous bars much exceeding the white ones in width; the whole maculate region with the shaft of each feather finely blackish. Anal region scarcely varied; lower tail-coverts immaculate, pure white. Lining of the wing white, with rather sparse cordate, or cuneate, small blackish spots; axillars barred about equally with pinkish-rufous and white. Wing, 6.60; tail, 5.70; tarsus, 1.78; middle toe, 1.20. Fifth quill longest; fourth but little shorter; third equal to sixth; second slightly shorter than seventh. Tail perfectly square.