Bill of moderate length, similar in form to that of Sylvicola, differing only in being a little decurved. The general form does not differ materially from that of Sylvicola, the head being ovate and of moderate size, the neck short, the body rather slender; the feet of moderate length, slender; tarsus slender, much compressed, longer than the middle toe with its claw, anteriorly covered with eight scutella, of which the upper are blended; toes of moderate size, hind toe proportionally large, lateral toes equal, fourth adherent at the base; claws rather long, arched, much compressed, laterally grooved, very acute. Plumage soft and blended. Wings rather short, convex, considerably rounded, the third and fourth quills longest, the fifth little shorter. Tail of moderate length, rounded, always plain, or without white spots. 100. 1. Trichas Macgillivrayi, Aud. Macgillivray's Ground-Warbler.--Macgillivray's Warbler. Plate CCCXCIX. Fig. 4. Male. Fig. 5. Female. Wings rather short, the second quill longest, the fourth longer than the first, the tail long, considerably rounded, its feathers rounded; tarsus longer than the middle toe and claw. Male olive-green above; the head, hind part, and sides of the neck bluish-grey; the fore neck and part of the breast greyish-black, lunulated with greyish-white; a black loral band; a conspicuous white spot on each eyelid; the lower parts bright yellow. Female olive-green above, yellow beneath, the sides of the neck and a band across the breast ash-grey. _Male_, 5-1/4, 6-1/2. _Female_, 5, wing 2-((4-1/2)/12). Columbia River. Common. Macgillivray's Warbler, Sylvia Macgillivrayi, Aud. Orn. Biog. v. v. p. 75. 101. 2. Trichas Philadelphia, Wils. Mourning Ground-Warbler.--Mourning Warbler. Wings of moderate length, with the second quill longest, the fourth shorter than the first; the tail long, considerably rounded, its feathers scarcely pointed; tarsus longer than the middle toe and claw. Male olive-green above, the head, hind part and sides of the neck, bluish-grey; the fore neck and part of the breast deep black, lunulated with white; a blackish loral band, margins of eyelids dusky grey; the lower parts bright yellow. Female olive-green above, yellow beneath, the sides of the neck and a band across the breast ash-grey, the throat yellowish-white. _Male_, 5, 8. New Jersey and Blue Mountains of Vermont. Rare. Migratory. Mourning Warbler, Sylvia Philadelphia, Wils. Amer. Orn. v. ii. p. 101. Sylvia Philadelphia, Bonap. Syn. p. 85. Mourning Warbler, Sylvia Philadelphia, Nutt. Man. v. i. p. 404. Mourning Warbler, Sylvia Philadelphia, Aud. Orn. Biog. v. v. p. 79. 102. 3. Trichas Marilandica, Linn. Maryland Ground-Warbler.--Maryland Yellow-throat. Yellow-breasted Warbler. Plate XXIII. Male and Female. Plate XXIV. Young Male.