CYPSELID.E — THE SWIFTS. 



431 



Genus CH^TURA, Stephens. 



Chaiura, Stephens, Shaw's Gen. Zool. Birds, XIII, ii, 1825, 76. (Type, C. pelagica.) 

 Acanthylis, BoiE, Lsis, 1826, 971. {Cypselus sjnnicauda.) 



Gen. Char. Tail very short, scarcely more than two fifths the wings ; slightly rounded ; 

 the shafts stiffened and ex- 

 tending some distance beyond 

 the feathers in a rigid spine. 

 First primary longest. Legs 

 covered by a naked skin, 

 without scutellge or feathers. 

 Tarsus longer than middle 

 toe. Lateral toes equal, 

 nearly as long as the middle. 

 Hind toe scarcely versatile, 

 or quite posterior ; including 



Ckdtura pelagica. 



claw, less than the middle anterior without it. Toes slender ; claws moderate. 

 of the base of the bill not extending beyond the beginning of the nostrils. 



Feathers 



By the arrangement of the genera on page 1018, the C. rutila and large 

 white-collared species are excluded from the present genus as restricted. 

 Chcetura, as here defined, is a genus of very extensive distribution, species 

 occurring not only in North and South America, but also in Africa and Asia. 

 Among the several American members, three styles are distinguishable, 

 these probably representing only as many species ; the several more closely 

 allied forms being, in all probability, but geographical modifications of these 

 three types. They may be arranged as follows : — 



Plumage ivith no marhed contrast of shades. 

 C. pelagica. Nearly uniformly dusky grayish-brown, the throat, however, 

 very much lighter, and the rump just appreciably so. 



Above glossy dusky-brown, hardly appreciably paler on the rump ; 

 abdomen scarcely paler than the back. Wing, 5.20. Hah. Eastern 



Province North America var. p elagica. 



Above glossy blackish-dusky, very decidedly paler on the rump ; 

 abdomen very much paler than the back. Wing, 4.50. Hub. Pacific 

 Province of North America, south to Guatemala (from whence speci- 

 mens are much darker, almost black above, and slightly smaller) var. vauxi. 



Above glossy black, fading into sooty dusky on the rump ; abdomen 

 like the rump. Wing, 4.80. Hob. Northern South America (Cayenne, 



Tobago) var. poliur a. ^ 



Plumage with marked contrast of shades. 

 C. cinereiventris.2 Upper parts, except the rump, glossy, intense blue- 

 black ; rump and lower parts bluish-cinereous, conspicuously different. 



1 Chmtura poliura, (Temm.) Sol. Cat. Am. B. 1862, 101 ; P. Z. S. 1866, 611. {Cypselus 

 polivurus, Temm. Tab. Meth. p. 78.) 



2 Chcetura cinercivcntris, ScL. Cat. Am. B. 1862, p. 283 ; P. Z. S. 1863, p. 101, pi. xiv, f. 1 ; 

 P. Z. 1866, 612. C. sclateri, Pelz. Orn. Braz. I, 1868, pp. 16, 56, is also referrible to it as 

 perhaps a race. 



