Wings rather short, with the third and fourth quills longest, fifth longer than second, first and sixth equal; tail considerably rounded, the lateral feathers being three-twelfths shorter than the middle. Male with a broad band of black across the forehead, including the loral space and eyes, and terminating in a rather pointed form behind the ear-coverts; over this band a narrow one of very pale blue, or bluish-white; upper parts yellowish-green, on the head slightly tinged with red; quills and tail-feathers wood-brown, margined with yellowish-green; the edge of the wing and the margin of the outer primary yellow; fore part of neck bright yellow, as is the anterior part of the breast and the lower tail-coverts, the rest pale, the sides shaded with dull yellowish-brown; the axillaries and some of the lower wing-coverts white. Female with the upper parts lighter, the lower less bright, tinged with reddish-brown, the head of pale brownish-red, without the bands so conspicuous in the male. Young similar to the female, the males with a black mystachial band. _Male_, 4-3/4, 6-1/2. From Texas northward to Nova Scotia, and throughout the interior; Columbia River. Maryland Yellow-throat, Sylvia Marilandica, Wils. Amer. Orn. v. i. p. 88, Male; v. ii. p. 163, Female. Sylvia Marilandica, Bonap. Syn. p. 85. Maryland Yellow-throat, Nutt. Man. v. i. Yellow-breasted Warbler, or Maryland Yellow-throat, Sylvia Trichas, Aud. Orn. Biog. v. i. p. 121, Adult; v. v. p. 463. Roscoe's Yellow-throat, Sylvia Roscoe, Aud. Orn. Biog. v. i. p. 124. Young. 103. 4. Trichas Delafieldii, Aud. Delafield's Ground-Warbler. Wing rather long, much rounded, with the third and fourth quills longest, sixth longer than second, first and tenth about equal; tail much rounded, the lateral feathers being half an inch shorter than the middle. Male with a band of black across the forehead, including the loral space and eyes, and terminating on the ear-coverts; upper part of head light greyish-blue, tinged behind with green; the rest of the upper parts dull yellowish-green; quills and tail-feathers wood-brown on the inner webs, the edge of the wing and margin of the outer primary yellow; all the lower parts rich yellow, excepting the sides, which are shaded into dull greenish-yellow. _Male_, 5-1/4, wing, 2-5/12. North California. Delafield's Yellow-throat, Sylvia Delafieldii, Aud. Orn. Biog. v. v. p. 307. GENUS IV. HELINAIA, Aud. SWAMP-WARBLERS.