_Strix ferruginea_, MAX. Reis. Bras. I, 105, 1820; Trav. Bras. p. 88; Beitr. III, 234.—TEMM. Pl. Col. 199.—LATH. Gen. Hist. I, 373. _Noctua f._, STEPH. Zoöl. XIII, pt. ii, p. 69.—LESS. Man. Orn. I, 111; Tr. Orn. 104.—CUV. Règ. An. (ed. 2), I, 346.—TSCHUDI, Av. Consp. Wiegm. Archiv. 1844, 267; Faun. Per. pp. 19, 117. _Surnia f._, BONAP. Oss. Cuv. Règ. An. p. 56; Isis, 1833, 1053. _Athene f._, GRAY, Gen. B. fol. sp. 17; List B. Brit. Mus. p. 92.—BONAP. Consp. Av. p. 38.—STRICKL. Orn. Syn. I, 162, 1855. _Glaucidium f._, KAUP, Mon. Strig. Cont. Orn. 1852, 104.—BURM. Thier. Bras. II, 141, 146.—CABAN. Ueb. Berl. Mus. 1869, 206.—COUES, Am. Nat. VI, 370 (Arizona).—IB. Key, 1872, 206. _? Athene nana_ (KING), GRAY, Gen. 1844, pl. xii (normal plumage). _a._ _Normal plumage._ SP. CHAR. _Adult_ (♂, 23,792, Mazatlan, Mexico; J. Xantus). Upper surface umber-brown, more ashy anteriorly, posteriorly more brownish. Head above with a few narrow longitudinal lines of yellowish-white, anteriorly and laterally; a quite distinct collar of whitish spots across the nape, the black lateral spaces rather obsolete; scapulars with a few conspicuous oval spots of pure white; two lower feathers of secondary coverts each with a similar spot on outer web. Secondaries darker brown, crossed with five bands of dull rufous, the last not terminal; outer webs of primaries with semicircular pale spots along the margin, these nearly white beyond the sinuation of the feathers, anteriorly brownish. Tail bright rufous, crossed with about seven distinct bands of dark brown, these hardly equalling the rufous in width, which is also terminal. Longitudinal stripes of the sides of the same soft grayish-brown tint as the head; tarsi sparsely speckled with the same on outer side. Wing-formula, 4, 5, 3–6–7, 2, 8; first shortest. Wing, 3.70; tail, 2.20; culmen, .45; tarsus, .70; middle toe, .70. _b._ _Rufescent plumage._ _Adult._ Upper surface continuously deep lateritious-rufous, all the lighter markings almost obliterated. Bars on the tail scarcely traceable. Black cervical transverse space conspicuous. Sides of the breast and stripes of the sides duller rufous than the tint above; white of ground-color with yellowish tinge; legs pale rufous, deepest on outer side, immaculate. Gular collar blackish. ♂ (43,055, La Palma, Costa Rica, January 27, 1866; José Zeledon). Wing-formula, 4=5, 3–6–2; first shortest. Wing, 3.80; tail, 2.40. ♀ (33,216, San José, Costa Rica; J. Carmiol). Wing-formula, 4, 3=5–6, 2; first shortest. Wing, 4.15; tail, 2.90; tarsus, .80; middle toe, .75. HAB. Whole of eastern South America, and Middle America (both coasts) north into southern border of United States (Arizona, BENDIRE; probably entire southern border). The numerous specimens examined come from the Rio Grande of Texas (across the whole breadth of Middle America) to Paraguay, everywhere the same species, those from the extremes of its range showing scarcely any difference.