Hirundo riparia. Tail, Fig. 1, slightly forked, margin of first quill smooth, tarsus with a tuft of feathers behind; upper parts greyish-brown, lower whitish, with a dusky band across the fore part of the neck.
Fig. 2.
Hirundo serripennis. Tail, Fig. 2, slightly emarginate, margin of first quill, Fig. 3, rough with the strong decurved tips of the barbs, tarsus bare; upper parts greyish-brown, lower pale greyish-brown, white behind.
Fig. 3.
In its general appearance, including proportions as well as colour, the Rough-winged Swallow is extremely similar to the Bank Swallow. It differs however in having the bill considerably longer, more attenuated toward the end, with the point of the upper mandible more decurved. The tail, Fig. 2, is shorter and but slightly emarginate, the lateral exceeding the middle feathers by only two-twelfths of an inch, whereas in the other species they exceed them by five-twelfths or even six; feathers are also broader and more rounded at the end. The wings are longer, and extend half an inch beyond the tail. The tarsi and toes are somewhat longer and more slender, and there are no feathers on the hind part of the tarsus as in the common species; the claws are much more slender.
The bill is black, the tarsi, toes, and claws dusky. The upper parts are of the same greyish-brown, or mouse-colour, as those of the Bank Swallow. The lower are of a very light greyish-brown, gradually paler on the hind parts, the abdomen and lower tail-coverts being white.
Length to end of tail 5 3/4 inches, to end of wings 6 1/4; extent of wings 12 1/2; bill along the ridge 3 1/2/12, along the edge of lower mandible 6 1/2/12; wing from flexure 4 4/12; tail to end of middle feather 1 10/12; to end of longest feather 2; tarsus 5/12; hind toe 2 1/4/12, its claw 2 1/4/12; middle toe 5/12, its claw 3 1/4/12.
In a specimen, from Charleston, South Carolina, preserved in spirits, the roof of the mouth is flat, the width of the gape 5 1/2 twelfths; the tongue triangular, 3 1/2 twelfths long, emarginate and papillate at the base, with two of the papillæ much larger, flat above, tapering to a slit point, more narrow and elongated than that of the Sand Swallow. The œsophagus is 1 inch 11 twelfths long, without dilatation, its breadth 1 1/2 twelfth. The stomach is elliptical, muscular, 5 twelfths long, being 4 1/2 twelfths, and placed a little obliquely; the epithelium brownish-red, tough, longitudinally rugous, filled with remains of insects. The intestine is 4 1/2 inches long; the cœca 1 1/2 twelfth in length, and 8 twelfths distant from the anus.