324 SYSTEMATIC SYNOPSIS —PASSEBES— OSCINES. 
Claws little curved, the lateral reaching beyond the base of the middle one. Bill very small, 
the nostrils opening laterally and overhung by a membrane. Tail much shorter than wings, 
emarginate. Coloration dull and simple — lustreless brown above and across breast, white 
below. Eggs uncolored, laid in holes in the ground excavated by the bird. Sexes alike. 
163. C. ripa'ria. (Lat. riparia, riparian ^ ripa, bank of a stream. Figs. 180, 184.) Bank 
Swallow. ^ 9 '• Lustreless mouse- 
brown ; wings and tail fuscous. Be- 
low, white, with a broad pectoral 
band of the color of the back. A 
dusky ante-orbital spot. Length 
about 5.00; extent 10.50; wing 
4.00; tail 2.00. Sexes similar; the 
young differ chiefly in whitish edg- 
ings of the feathers, especially of 
the wings and tail. Even in the 
adult, the upper parts are apt to 
be not quite uniform, there being 
paler gray edgings of most of the 
feathers. The dark pectoral band 
sometimes extends backward along 
the middle of the under parts (not 
shown in fig. 184). Autumnal speci- 
mens have the secondaries white- 
tipped. Very young birds have 
rather rusty than whitish skirting 
of the dark feathers, and the white 
throat speckled w^ith the same. Al- 
most cosmopolitan : Europe, Asia, 
Africa, America; abundant in N. 
Am., breeding in immense troops in holes in the ground, wherever suitable sites ofi'er, as 
natural embankments, rail-road cuttings, gravel-pits, etc. 
54. STELGIDO'PTERYX. (Gr. areXyis, stelgis, a scraper ; nrepv^, pterux, wing.) Eough- 
wiNGED Swallows. General aspect of Cotile ; form and coloration mu(.'h the same. Outer 
web of 1st primary converted into a series of stiff, recurved hooks. (Other Swallows, as Psali- 
doprocne Cab., have this peculiar wing structure, but are otherwise different.) The design of 
the structure is not clear, but we may readily suppose that the hooks assist the birds in crawl- 
ing into their holes, and in clinging to vertical or hanging surfaces. Tarsus slightly feathered 
above, but lacking the curious tuft seen at the base of the hind toe in Cotile. Lateral claM'S 
curved, and not reaching beyond the base of the middle. Basal joint of middle toe exten- 
sively adherent to the outer, much less so to the inner. Bill small, with oval, superior nostrils 
margined by membrane behind, but not overhung. Tail short and slightly emarginate. Eggs 
uncolored, in holes dug by the birds, or elsewhere. Sexes alike. 
164. S. serripen'nis. (Lat. serra, a saw; _/9emia, a feather.) Rough-winged Swallow. ^ ^: 
Lustreless mouse-brown or brownish-gray, paler below, gradually whitening posteriorly. 
Wings and tail darker than the upper parts. Bather larger than the last species. No dark 
pectoral band contrasting with white. No tuft of feathers at the base of the hind toe. Young: 
At a very early age, the feathers of the back, rump, and wings are suffused or edged with rich 
rusty-brown, while the under parts are more or less tinged with a paler shade of the same. 
The booklets of the wings are only fully developed in adult birds, and are not appreciable at 
all in young ones. U. S. and adjoining British Provinces ; rare in Eastern States. 
Fig. 184. -Bank Swallow. (Designed by H. W. Elliott.) 
