302 NORTH AMERICAN BIRDS. 
Famity MICROPODIDAE.—Tue Swirrs. (Page 297.) 
Genera. 
a’. Tarsi and part of toes feathered, the hind-toe directed either forward or laterally, 
not backward. (Subfamily Micropodine.)......... Aéronautes. (Page 303.) 
a. Tarsi and toes naked, the hind-toe directed backward. (Subfamily Cheturine.) 
o'. Tail rounded, or even, the feathers usually with distinct spinous points; 
Wing less than 5.50 ......csecesssscsesseeseessecenseeetes Cheetura. (Page 302.) 
6. Tail slightly forked, or emarginate. 
ce. Tail-feathers without spinous points; wing less than 7.00; no white 
COMB sscainteasivens sev esereasboxnmersncs scones Cypseloides. (Page 302.) 
ce. Tail-feathers with distinct, though small, spinous points; wing 8.00 or 
More ; a White COMAL scicsccvsssicvecesiovneecavercsedesveaswines Hemiprocneo 
Genus CYPSELOIDES Srrevusex. (Page 302, pl. LXXXIX., fig. 2.) 
Species. 
Adult: Uniform dusky or blackish, becoming more sooty grayish on head and 
neck, the forehead more hoary. Young: Similar, but feathers bordered terminally 
with whitish. Length about 7.00-7.50, wing 6.50-7.50, tail 2.30-3.00. Hab. 
Western United States (north to Colorado, Nevada, and British Columbia), and 
south to Costa Rica; Jamaica, Haiti, and other West India islands. 
422. C. niger (GmEL.). Black Swift. 
Genus CHAETURA Srepuens. (Page 302, pl. LXXXIX., fig. 3.) 
Species. 
Common CuHaracters.—Plain dusky, or dark sooty grayish, above, the wings 
darker, the rump, upper tail-coverts, and tail usually paler; lower parts plain sooty 
grayish, darker posteriorly, paler (sometimes dull whitish or whitish gray) ante- 
riorly. Or else, uniform sooty, the throat not paler (C. brunneitorques, 9), or black- 
ish, with broad collar of rufous round neck (C. brunneitorques, ). 
a. Throat distinctly paler than other parts; male without rufous collar. 
. Wing 5.00, or more. 
Length about 4.75-5.50, wing 5.00-5.25, tail (including spines) 1.90- 
2.15. Nest a shallow half-saucer-shaped structure of dried twigs, 
glued together with the bird’s saliva, and with the same adhesive sub- 
stance fastened to the inside of a hollow tree (with the entrance from 
above), a disused chimney, or similar place. Hggs 4-6, .79 x .52, ellip- 
1 Hemiproene Nirzscu, Pterylog. 1840, 123. Type, by elimination, Hirundo zonaris Suaw. 
This genus includes two Mexican species—the largest members of the family—either of which may possibly 
occur as a straggler within our southwestern border. 
