Tyrannus couchi, Baird, Birds N. Am. 1858, 175, pl. xlix, f. 1.—Scl. Catal. Am. B. 1862, 235.
Sp. Char. Bill long as the head. Feet stout. Five outer primaries abruptly attenuated at the end; the third and fourth longest; the first a little longer than the sixth. Tail considerably forked (depth of fork about .30 of an inch, or more). Head, neck, and jugulum bluish-ashy, becoming nearly white on the throat, and shaded with yellow on the breast. Rest of lower parts gamboge-yellow. Rest of upper parts olive-green, tinged with ash anteriorly. Tail and primaries grayish-brown, the tail not the darker. Wing-coverts passing externally into pale, the tertials edged with almost white. Crown with a concealed patch of bright orange-red. Length, 9.00; wing, 5.00; tail, 4.70.
Hab. Middle America (both coasts), from southern border of United States, south to Guatemala; Tucson, Arizona (Bendire).
All specimens of T. melancholicus from regions north of Guatemala are referrible to var. couchi; all from Costa Rica southward, to melancholicus.
It is only by comparing specimens from near the extreme northern and southern limits of the range of the species, that differences are readily discernible; and between these two extremes there is so gradual a transition that it is impossible to draw a line separating two well-marked varieties, so that it is necessary to assume an arbitrary geographical line, and determine specimens from the middle regions by their position, whether to the north or south of the line established. Specimens from Buenos Ayres, the Parana, and Brazil, to Peru and New Granada, are identical. Costa Rica specimens (T. satrapa, Licht.) have the dark tail of var. melancholicus and white throat of couchi.
Genus MYIARCHUS, Cabanis.
Myiarchus, Cabanis, Fauna Peruana, 1844-46, 152.—Burmeister, Thiere Brasiliens, II, Vögel, 1856, 469.
Gen. Char. Tarsus equal to or not longer than the middle toe, which is decidedly longer than the hinder one. Bill wider at base than half the culmen. Tail broad, long, even, or slightly rounded, about equal to the wings, which scarcely reach the middle of the tail; the first primary shorter than the sixth. Head with elongated lanceolate distinct feathers. Above brownish-olive, throat ash, belly yellow. Tail and wing feathers varied with rufous.
This genus is well marked among the American Flycatchers, and constitutes what Bonaparte called Ultimi Tyrannorum sive Tyrannularum primæ. The type is the Muscicapa ferox of Gmelin, (M. tyrannulus,) which, as identified by Cabanis and Burmeister as above, appears to resemble our species very closely.
