The Setophaginæ have their greatest development in Middle and South America, no less than nine genera and subgenera being on record, of which only two extend into the United States. Of one of these, Setophaga, we have only a single species of the many described; the other, Myiodioctes, has no members other than those found in the United States.
The following diagnosis is prepared to distinguish our genera from the South American:—
A. Wings pointed; the first quill longer than the fifth; the third as long as or longer than the fourth. Tail nearly even, or slightly rounded (the difference of the feathers less than .20); the feathers broad and firm; the outer webs of exterior feathers narrow at base, but widening to nearly double the width near the end.
1. Bill from gape nearly as long as skull, broad at base and much depressed; rictal bristles reaching half-way from nostrils to tip. Culmen and commissure nearly straight. Wings equal to the tail. Tarsi long; toes short; middle toe without claw, about half the tarsus … Setophaga.
2. Bill from gape nearly as long as skull, broad at base, but deep and more sylvicoline; rictal bristles reaching but little beyond nostrils. Culmen and commissure straight to the tip. Wings longer than the almost even tail. Middle toe without claw, three fifths the tarsus … Myiodioctes.
3. Bill from gape much shorter than head, wide at base, but compressed and high; the culmen and commissure much curved from base, scarcely notched at tip; rictal bristles reaching nearly half-way from nostrils to tip. Wings about equal to the almost even tail. Middle toe without claw, about three fifths the rather short tarsus … Cardellina.
B. Wings rounded; the first quill shorter than in the preceding section; always less than the fifth. South American genera.[59]
Several species of Setophaginæ have, on not very well established grounds, been assigned to the southern borders of the United States. They are as follows:—
Cardellina rubra, Baird, Rev. Am. Birds, 1865, 264. (Setophaga rubra, Swainson.) Parus leucotis, Giraud, Birds Texas. Hab. Mexico. Rich carmine-red. Wing and tail-feathers brown. Ear-coverts silvery white. Length, 4.70; wing, 2.40; tail, 2.55.
Basileuterus culicivorus, Baird, Rev. Am. Birds, 1865, 246. (Sylvia culicivora, Licht. ) Muscicapa brasieri, Giraud, Texas Birds. Hab. Southern Mexico; Guatemala and Costa Rica. Top of head with two black stripes enclosing a median of yellow. Back olivaceous-ash. Beneath entirely yellow. No rufous on side of head. Length, 4.90; wing, 2.40; tail, 2.25.