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 Rica.) Chaetura richmondi (p. 719). 



ee. Paler, especially under parts; rectrices without distinct (if any) spiny 

 tips (except in very fi-esh plumage); wing averaging 105.5, tail 27.7, 

 in male, wing 105.2, tail 30.1, in female. (Yucatan.) 



Chaetura gaumeri (p. 721). 

 cc. Under parts and rump much paler brownish gray. (Western North America, 



south in winter to Guatemala.) Chaetura vauxii (p. 722). 



hh. 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). 



:•. 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.) Chaetura 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 Triniddd to eastern Brazil.) 



Chaetura spinicauda (extralimital).« 

 cc. Pileum and back glossy black. {Chaetura cinereiventr is. b) 

 d. Upper tail-coverts black or blackish, in contrast with pale gray of rump. 

 €. Under parts of body paler; slightly smaller (wing 110 mm.). (Eastern 



Brazil.) Chaetura cinereiventris cinereiventris (extralimital).c 



ee. Under parts of body darker; slightly larger (wing 111.1 mm.). (Pacific 

 coast district from Costa Rica to northern Colombia.) 



Chaetura cinereiventris fumosa (p. 725). 



a Hirundo spinicauda [Temminck?] Catal. Naamlyst Vog. Johan. Sonnenberg 

 Galant, 1810, 13 (based on VHirondelle acutipenne Buffon, Hist. Nat. Ois., vi, 701; 

 Hirondelle a quexie pointue de Caijenne Daubenton, PI. Enl., 726, fig. 1); Kuhl, 

 Buff, et Daub. Fig. Av. Col. Nom. Syst., 1820, 13 (credits name to Temminck). — 

 Cypselus spinicaudus Temminck, Tabl. Moth., 1839, 78. — Acanihylis spinicauda Boie, 

 Isis, 1826, 971; 1844, 167 .—Chsetura spinicauda Sclater, Cat. Am. Birds, 1862, 283; 

 Hartert, Cat. Bu-ds Brit. Mus., xvi, 1892, 483; Das Tierreich, Podarg., Caprimulg., 

 Macropt., 1897, 75. — Chxtura 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) [Chxtura cinereiventris] Subsp. a. Chxtura guianensis Hartert, Cat. Birds Brit. 

 Mus., xvi, 1892, 486. — Chxtura cinereiventris guianensis Hellmayr, Verh. Orn. Gesellsch. 

 Bayern, viii, 1908, 155. 



(2) Chxtura sclateri Pelzeln, Orn. Bras., 1868, 15, 56. — Chxtura cinereiventris sclateri 

 Hellmayr, Verh. Orn. Gesellsch. Bayern, viii, 1908, 157. 



(3) Chxtura sclateri occidentalis Berlepsch and Taczanowski, Proc. Zool. Soc. Lond., 

 1883, 569. — Chxtura cinereiventris occidentalis Hellmayr, Verh. Orn. Gesellsch. 

 Bayern, viii, 1908, 158. 



c Chxtura 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, 1830, 351 

 (Brazil; coll. Am. Mus. N. H.). 



