General colour dull brownish-grey; quills and coverts dusky brown; edge of wing dull white; basal part of primaries pale yellow, of secondaries ochre-yellow; edges of all the quills dull greyish-white; secondaries with a faint patch of light brownish-grey on the outer web toward the end; middle tail-feathers greyish-brown, the rest blackish-brown, the outer with an oblique white space, including, from the tip, a considerable portion of the inner web, and more than two-thirds of the outer; the next with a white patch at the end; lower parts paler than the upper; lower tail and wing-coverts broadly tipped with dull white, some of the inner wing-coverts white. _Female_, 8-1/4, wing, 4-1/2. Columbia River. Townsend's Ptilogonys, Ptilogonys Townsendi, Aud. Orn. Biog. v. v. p. 206. GENUS IV. CULICIVORA, Swains. GNAT-CATCHER. Bill of moderate length, depressed at the base, rapidly attenuated, becoming very slender toward the end; upper mandible with the ridge distinct, the tip extremely narrow and deflected, the edges overlapping, the notch distinct, but very small; lower mandible with the angle of moderate length, the ridge narrowed towards the end, the edges inclinate, the tip acute. Nostrils oblong, exposed. Head ovate; neck short; body slender. Feet of moderate length, tarsus longer than the middle toe, extremely slender, with the upper scutella indistinct; toes very small, extremely compressed; hind toe proportionally very large; outer adherent at the base. Claws well arched, extremely compressed, laterally grooved, acute. Plumage very soft and blended. Wings of moderate length, concave; the first quill about a third of the length of the second, fourth longest, third and fifth little shorter. Tail long, slender, much rounded. 70. 1. Culicivora cœrulea, Lath. Blue-grey Gnat-catcher. Plate LXXXIV. Male and Female. Upper parts bright blue, deeper on the head, paler on the tail-coverts; a narrow black band on the forehead, extending over the eyes; wings brownish-black, margined with blue, some of the secondaries with bluish-white; tail glossy black, the outer feather on each side nearly all white, the next with its terminal half, and the third with its tip of that colour; lower parts greyish-white. Female similar, but with the tints duller, and the black band on the head wanting. _Male_, 4-1/2, 6-1/2. From Texas northward. Abundant. Migratory. Blue-grey Flycatcher, Muscicapa cœrulea, Wils. Amer. Orn. v. ii. p. 164. Sylvia cœrulea, Bonap. Syn. p. 85. Blue-grey Sylvan Flycatcher, Muscicapa cœrulea, Nutt. Man. v. i. p. 297. Blue-grey Flycatcher, Muscicapa cœrulea, Aud. Orn. Biog. v. i. p. 431. FAMILY VIII. SYLVICOLINÆ. WOOD-WARBLERS.