Head rather large; neck short; body slender. Feet very short; tarsus slender, compressed, with six anterior scutella, which are so large below as almost to meet behind; toes free, slender, of moderate length. Claws moderately arched, much compressed, acute.
Plumage soft and blended. Strong bristles along the basal margin of the upper mandible, and over the nostrils. Wings rather long, broad; the first five primaries much attenuated toward the end, the first more so, the fifth least; this attenuation being chiefly produced by an incision on the first web; the first four are nearly equal, the third longest, the fourth half a twelfth shorter, the third one-twelfth shorter than the hind, and exceeding the first by nearly two-twelfths; the other primaries gradually broader and more rounded; outer secondaries abrupt and slightly emarginate. Tail rather long, almost even, of twelve broad, abruptly rounded and acuminate feathers.
Bill black. Iris brown. Feet and claws black. The general colour of the upper parts is ash-grey, the back tinged with yellow; the wing-coverts and quills chocolate-brown, with brownish-white edges, those of the inner secondaries broader. Upper tail-coverts and tail black, excepting the outer web of the lateral feather on each side, and the basal margin of the next. There is a patch of bright vermilion on the top of the head, tinged with orange-yellow behind. Throat greyish-white, the sides and fore part of the neck pale ash-grey, shaded on the fore part of the breast into pure yellow, which is the prevalent colour of the lower parts; lower wing-coverts yellow, the middle ones tinged with grey.
Length to end of tail 9 inches, to end of wings 7, to end of claws 7, extent of wings 15 1/4; tail 3 7/8; wing from flexure 5 1/2; bill along the ridge 9/12, along the edge of lower mandible 1 1/12; tarsus 8 1/2/12; first toe 3 1/2/12, its claw 4 1/2/12; third toe 7/12, its claw 4/12.
Adult Female. Plate CCCLIX. Fig. 2.
The Female is rather smaller, but is similar to the male in colouring.
The young also is similar to the adult, but wants the red patch on the head.
In the female mentioned above as having been found in Texas, the mouth is half an inch wide, its roof anteriorly slightly concave, with three median prominent lines, the palate flat, with its membrane or skin diaphanous, as in Goatsuckers. The tongue is 7 twelfths long, deeply emarginate and papillate at the base; triangular, extremely depressed, tapering to a thin slit and bristly point. The posterior aperture of the nares is 4 twelfths long, linear, papillate on the edges, ending abruptly at its fore part, without a prolonged fissure. Œsophagus, a, a, b, 2 inches 9 twelfths long, funnel-shaped for half an inch, then cylindrical and nearly 4 twelfths in diameter, until it enters the thorax. Proventriculus, c, 3 1/2 twelfths in diameter, and with a belt of oblong glandules. Stomach c, d, elliptical, 7 1/2 twelfths long, 6 twelfths broad, its lateral muscles of moderate strength, the lower not distinct; the epithelium with broad longitudinal rugæ, and of a dark reddish-brown colour. Intestine, e, f, g, 7 inches long, its diameter at the anterior part 3 1/2 twelfths, gradually diminishing to 1 1/2 twelfth. Cœca extremely small, 1 twelfth long, 1/2 twelfth broad, and 1 1/4 inch distant from the anus; cloaca i, globular.
Trachea 1 inch 10 twelfths long, tapering from a diameter of 2 twelfths to 1 twelfth; the rings ossified and firm, about 70 in number; the lateral and sterno-tracheal muscles slender; the inferior laryngeal muscles are strong but very short, forming a prominent knob, and attached to the first bronchial ring. Bronchi wide, of about 20 half-rings.