Setophaginæ. Bill, _tyrannine_, considerably broader than high, the tip more or less hooked, and with a distinct notch. Rictal bristles reaching half-way, or more, to the tip. Sections and Genera. SYLVICOLINÆ. 1. Middle toe, with claw, longer than tarsus. Mniotilteæ. Bill much compressed for terminal half, the lateral outline decidedly concave; culmen and gonys decidedly convex; commissure moderately concave. Rictal bristles very inconspicuous; notch just perceptible … _Mniotilta._ 2. Middle toe, with claw, not longer than tarsus. Vermivoreæ. Bill without a distinct notch, or lacking it entirely; rictal bristles wanting, or very minute; culmen and gonys nearly straight; bill only very moderately compressed. _a._ Middle toe and claw about equal to tarsus. Bill not acute; culmen and gonys decidedly convex; notch just perceptible; bristles apparent … _Protonotaria._ Bill moderately acute, robust; no notch; culmen straight, its base elevated and slightly arched; bristles not apparent … _Helinaia._ Bill moderately acute; robust; no notch; culmen convex, its base not elevated; bristles apparent … _Helmitherus._ _b._ Middle toe and claw considerably shorter than tarsus. Bill very acute, its outlines nearly straight; notch not perceptible; bristles not apparent … _Helminthophaga._ Bill very acute, its outlines nearly straight; notch just perceptible; bristles strong … _Parula._ Sylvicoleæ. Bill distinctly notched; rictal bristles strong; outlines generally slightly curved. Bill acute, gonys slightly concave … _Perissoglossa._ Bill not acute, gonys convex … _Dendroica._ GEOTHLYPINÆ. 3. Wings pointed, longer than the nearly even tail. Seiureæ. Above olive-brown; beneath white with dark streaks … _Seiurus._ Above olive-green; beneath yellow without streaks … _Oporornis._ 4. Wings rounded, shorter than the graduated tail. Geothlypeæ. Above olive-green; beneath yellow, without streaks … _Geothlypis._ ICTERIANÆ. 5. Bill very deep and compressed; tail graduated; outer toe deeply cleft. Icterieæ. Olive-green above; bright yellow anteriorly beneath. Upper mandible deeper than the lower … _Icteria._ Plumbeous-blue above; red, black, and white beneath. Upper mandible not so deep as the lower … _Granatellus._ 6. Bill slender, sub-conical, but curved; tail nearly even; outer toe adherent for basal half. Teretristeæ. Above olive-gray; beneath whitish posteriorly, and yellow anteriorly … _Teretristis._ SETOPHAGINÆ.