716 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 
dd. Smaller (wing 105-116.5 mm.); pileum and back blackish. 
e. Darker; rectrices with conspicuous spiny tips; wing averaging 111.2, 
tail 36.2, in male, wing 111.8, tail 37.1, in female. (Eastern Mexico to 
Costa Ricd.) sci ecde srs wena aneeeene ee Chetura richmondi (p. 719). 
ee. Paler, especially under parts; rectrices without distinct (if any) spiny 
tips (except in very fresh plumage); wing averaging 105.5, tail 27.7, 
in male, wing 105.2, tail 30.1, in female. (Yucatan.) 
Chetura gaumeri (p. 721). 
cc. Under parts and rump much paler brownish gray. (Western North America, 
south in winter to Guatemala.).................-. Cheetura vauxii (p. 722). 
bb. Rump clearer gray, ash gray, or pale buffy gray, contrasting with the black 
or blackish tail as well as with black or dark sooty of back; tail relatively 
longer (one-third or more as long as tail). 
s. Pileum and back dark sooty. 
d. Rump deep brownish gray or sooty gray, shading gradually into the darker 
color of upper tail-coverts. (Dominica, Guadeloupe, and Santa Lucia, 
Lesser Antilles.).........2.--.---0.-20.-202 eee Chetura acuta (p. 724). 
dd. Rump pale buffy gray, forming a broad and sharply defined band, ab- 
ruptly contrasted with dark sooty or sooty blackish of back and upper 
tail-coverts. (Guianas and Trinid4d to eastern Brazil.) 
Cheetura spinicauda (extralimital).¢ 
ce. Pileum and back glossy black. (Chextura cinereiventris.b) 
d. Upper tail-coverts black or blackish, in contrast with pale gray of rump. 
e. Under parts of body paler; slightly smaller (wing 110 mm.). (Eastern 
Brazil.) ...........Chztura cinereiventris cinereiventris (extralimital).¢ 
ee. Under parts of body darker; slightly larger (wing 111.1mm.). (Pacific 
coast district from Costa Rica to northern Colombia.) 
Chzetura cinereiventris fumosa (p. 725). 
a Hirundo spinicauda [Temminck?] Catal. Naamlyst Vog. Johan. Sonnenberg 
Galant, 1810, 13 (based on l’Hirondelle acutipenne Buffon, Hist. Nat. Ois., vi, 701; 
Hirondelle & queue pointue de Cayenne Daubenton, Pl. Enl., 726, fig. 1); Kuhl, 
Buff. et Daub. Fig. Av. Col. Nom. Syst., 1820, 13 (credits name to Temminck).— 
Cypselus spinicaudus Temminck, Tabl. Méth., 1839, 78.—Acanthylis spinicauda Boie, 
Isis, 1826, 971; 1844, 167.—Chetura spinicauda Sclater, Cat. Am. Birds, 1862, 283; 
Hartert, Cat. Birds Brit. Mus., xvi, 1892, 483; Das Tierreich, Podarg., Caprimulg., 
Macropt., 1897, 75.—Chetura spinicauda spinicauda Hellmayr, Verh. Orn. Gesellsch. 
Bayern, viii, 1908, 158 (range; synonymy; descr.). 
b The following forms, referred to this species, as subspecies, by Hellmayr, I have 
not seen: 
(1) [Chetura cinereiventris] Subsp. a. Chetura guianensis Hartert, Cat. Birds Brit. 
Mus., xvi, 1892, 486.—Chextura cinereiventris guianensis Hellmayr, Verh. Orn. Gesellsch. 
Bayern, vili, 1908, 155. 
(2) Chetura sclatert Pelzeln, Orn. Bras., 1868, 15, 56.—Chetura cinereiventris sclateri 
Hellmayr, Verh. Orn. Gesellsch. Bayern, viii, 1908, 157. 
(3) Chetura sclateri occidentalis Berlepsch and Taczanowski, Proc. Zool. Soc. Lond., 
1883, 569.—Chextura cinereiventris occidentalis Hellmayr, Verh. Orn. Gesellsch. 
Bayern, viii, 1908, 158. 
¢ Chetura cinereiventris Sclater, Cat. Am. Birds, 1862, 283; Hartert, Cat. Birds 
Brit. Mus., xvi, 1892, 485.—Ch[xtura] cinereiventris* (typica) Hartert, Das Tierreich, 
Podarg., Caprim., Macropt., 1897, 76.—Chaetura cinereiventris cinereiventris Hellmayr, 
Verh. Orn. Gesellsch. Bayern, viii, 1908, 153 (e. Brazil; synonymy; descr.).— 
Cypselus acutus (not Hirundo acuta Vieillot) Maximilian, Beitr., iii, pt. i, 1880, 351 
(Brazil; coll. Am. Mus. N. H.). 
