BIRDS OF NORTH AND MIDDLE AMERICA. 721 
dido; Costa Rica; Chiriquf).—DrarBorn, Pub. 125, Field Mus. N. H., 1907, 
96 (Los Amates, e. Guatemala, Jan.).—Carrixer, Ann, Carnegie Mus., vi, 
1910, 507 (Costa Rica).—Frrry, Pub. 146, Field Mus. N. H., orn. ser., i, 
no. 6, 1910, 264 (Guayabo, Costa Rica). 
Clhetura] gaumert Ripeway, Man. N. Am. Birds, 1887, 303, part (Costa Rica). 
Ch{xtura] gaumert Hartert, Das Tierreich, Podarg., Caprim., Macropt., 1897, 
75, part (Nicaragua; Costa Rica). 
[Cheztura] gaumeri SHarpe, Hand-list, ii, 1900, 92, part (Nicaragua; Costa Rica). 
Chetura vauxii (not Cypcelus vaucii Townsend) Lawrence, Bull. U. 8. Nat. 
Mus., no. 4, 1876, 32 (Guichicovi, Oaxaca). 
Chetura vauxi Savin and Gopman, Biol. Centr.-Am., Aves, ii, 1894, 375, part 
(Guichicovi, Oaxaca; Rio Escondido, Nicaragua; Costa Rica; Honduras?).— 
CaRRIKER, Ann. Carnegie Mus., vi, 1910, 507 (Costa Rica). 
Chetura richmond: Ripeway, Proc. Biol. Soc. Wash., xxiii, Apr. 19, 1910, 53 
(Guayabo, e. Costa Rica; coll. U. 8. Nat. Mus.).—Psinures, Auk, xxviii, 
1911, 77 (Carricitos and Guiaves, Tamaulipas). 
CHETURA GAUMERI Lawrence. 
GAUMER’S SWIFT. 
Similar to C. richmondi, but decidedly smaller (except bill and 
feet), paler, especially the rump, upper tail-coverts, and under parts, 
and rectrices without distinct (if any) projecting tip to shaft of rec- 
trices (except, sometimes, in very fresh plumage). 
Adults (sexes alike).—Lores velvety black; pileum, hindneck, back, 
and scapulars uniform very dark sooty brown or blackish brown, 
faintly glossed with greenish, the wings similar but more nearly 
black and with the gloss more bluish green; rump and upper tail- 
coverts grayish brown (hair brown, decidedly lighter than in C. 
richmondt), the feathers usually (%) narrowly and indistinctly tipped 
with paler; tail slightly darker grayish brown, the shafts of rectrices 
black; under parts grayish brown (hair brown), gradually becoming 
slightly paler on chest, where fading into much paler gray (sometimes 
almost grayish white) on chin and upper throat; bill black; iris brown; 
legs and feet dusky (more or less livid in life). 
Young.—Not materially, if at all, different in coloration from adults. 
Adult male.—Length (skins), 109: wing, 105-106 (105.5); tail, 26- 
29.5 (27.7); culmen, 5; tarsus, 11; middle toe, 7.5.¢ 
Adult female.—Length (skins), 95.5—99.5 (97): wing, 99-111 (105.2); 
tail, 28-31.5 (30.1); culmen, 4.5-5 (4.6); tarsus, 10-10.5 (10.2); 
middle toe, 7-7.5 (7.3).° 
Yucatan (Mérida; Chichen-Itza; Temax; La Vega; Silam; Tunkas; 
Tictl; Cozumél Island). 
@ Two specimens. 
b Four specimens. 
Although the series examined of this form is a very large one, most of the specimens 
have not the sex determined. 
81255°—Bull. 50—11——46 
