Two outer tail-feathers entirely white. A narrow frontal line, extending back over the eye, black. _Hab._ North America … _P. cærulea._ Outer tail-feather, with the whole of the outer web (only), white. No black on the forehead, but a stripe over the eye above one of whitish. _Hab._ Arizona … _P. plumbea._ _Top of head black._ Edge only of outer web of outer tail-feather white. Entire top of head from the bill black. _Hab._ Rio Grande and Gila … _P. melanura._ Species occur over the whole of America. One, _P. lembeyi_, is peculiar to Cuba, and a close ally of _P. cærulea_. Polioptila cærulea, SCLAT. BLUE-GRAY GNATCATCHER; EASTERN GNATCATCHER. _Motacilla cærulea_, LINN. Syst. Nat. I, 1766, 337 (based on _Motacilla parva cærulea_, EDW. tab. 302). _Culicivora cærulea_, CAB. Jour. 1855, 471 (Cuba).—GUNDLACH, Repert. 1865, 231. _Polioptila cærulea_, SCLATER, P. Z. S. 1855, 11.—BAIRD, Birds N. Am. 1858, 380.—IB. Rev. 74.—DRESSER, Ibis, 1865, 231.—COOPER, Birds Cal. 1, 35. _Motacilla cana_, GM. S. N. I, 1788, 973. _? Culicivora mexicana_, BON. Consp. 1850, 316 (not of CASSIN), female. _Polioptila mexicana_, SCLATER, P. Z. S. 1859, 363, 373. Figures: VIEILL. Ois. II, pl. lxxxviii.—WILSON, Am. Orn. II, pl. xviii, fig. 3.—AUD. Orn. Biog. I, pl. lxxxiv; IB. Birds Am. I, pl. lxx. SP. CHAR. Above grayish-blue, gradually becoming bright blue on the crown. A narrow frontal band of black extending backwards over the eye. Under parts and lores bluish-white tinged with lead-color on the sides. First and second tail-feathers white except at the extreme base, which is black, the color extending obliquely forward on the inner web; third and fourth black, with white tip, very slight on the latter; fifth and sixth entirely black. Upper tail-coverts blackish-plumbeous. Quills edged externally with pale bluish-gray, which is much broader and nearly white on the tertials. Female without any black on the head. Length, 4.30; wing, 2.15; tail, 2.25. (Skin.) HAB. Middle region of United States, from Atlantic to Pacific, and south to Guatemala; Cape St. Lucas. Cuba, GUNDLACH and BRYANT. Bahamas, BRYANT. HABITS. The Blue-gray Flycatcher is a common species from the Atlantic to the Pacific coast, although not met with in the New England States. It is less abundant on the coast than at a distance from it, and has a more northern range in the interior, being met with in Northern Ohio, Michigan, and the British Provinces. Specimens occur in the Smithsonian Institution collection from New York to Mexico and Guatemala, and from Washington Territory to California.