Obs. This minute species of Owl is exclusively Western, having as yet only been noticed in California. It much resembles the European _Glaucidium passerinum_, and is about the same size. The most readily detected differences are the nearly naked toes of the present bird, and the absence of the decided reddish tinge which prevails in the color of the European species. It also resembles _G. passerinoides_ of South America, but differs also from that species in color and other particulars. This is the least of the species of Owls inhabiting North America, and has never been observed east of the Rocky Mountains. It lives on insects. V. SUB-FAMILY NYCTEININÆ. THE DAY OWLS. Head moderate, without ear-tufts; wings rather long, wide; tail rather long, ample; tarsi strong, and with the toes densely covered with hair-like feathers; claws strong, sharp; plumage very thick and compact. This sub-family includes only the two species now about to be described, both of which are common to the Arctic regions of America, Europe, and Asia, migrating southward in the winter. They are the least nocturnal of all the birds of this family. I. GENUS NYCTEA. Stephens, Cont. of Shaw’s Gen. Zool., XIII. p. 62. (1826.) Size large; head large, without ear-tufts; no facial disc; bill short, very strong, nearly concealed by projecting feathers; wings long, wide, third quill longest; tail moderate or rather long, broad; legs short, and with the toes densely covered with feathers, almost concealing the claws, which are long, curved, and strong; general form compact and robust, and thickly feathered. This genus contains only the species described below. Nyctea nivea. (Daudin.) The Snowy Owl. The White Owl. Strix nivea. Daudin, Traité d’Orn., II. p. 190. (1800.) Strix nyctea. Linn., Syst. Nat., I. p. 132. (1766.) Strix candida. Lath., Ind. Orn., Supp., p. 14. (1801.) Strix erminea. Shaw, Gen. Zool., VII. p. 251. (1809.) Strix arctica. Bartram, Trav., p. 289 (1791, but not of Sparrman, 1789.) Large; eyes large; bill nearly concealed by projecting feathers; tarsi and toes densely covered with hair-like feathers, nearly concealing the claws. Adult. Entire plumage white, in some specimens with a few spots only on the upper parts of dark brown, and on the under parts with a few irregular transverse bars of the same; quills and tail with a few spots or traces of bands of dark brown. In other specimens every feather except on the face and neck before, is distinctly banded transversely with brown, and in some specimens that color predominates on the upper parts; quills and tail with regular transverse bands of dark brown; plumage of the legs and feet pure white; bill and claws dark horn-color; irides yellow. Dimensions. _Female._—Total length, 24 to 26 inches; wing, 17; tail, 10 inches. _Male_, smaller.