BIRDS OF NORTH AND MIDDLE AMERICA. 717 
dd. Upper tail-coverts gray, or mostly so, like rump. 
e. Upper tail-coverts partly blackish; under parts of body paler (as in 
C. c. cinereiventris). (Grenada, Tobago, Trinid4d, and Margarita Island, 
Venezuela.)...........------ Cheetura cinereiventris lawrencei (p. 727). 
ee. Upper tail-coverts entirely gray, like rump; under parts of body darker 
(as in C. c.fumosa). (Caribbean slope, Nicaragua and Costa Rica.) 
Cheetura cinereiventris pheeopygos (p. 727). 
aa. Under parts of body black, or sooty black, conspicuously darker than color of 
tail and tail-coverts. (St. Vincent and Grenada, Lesser Antilles; Tobago, 
and Trinidid to Venezuela, eastern Peru, and northern Brazil.) 
Cheetura brachyura (p. 728). 
I am fully aware of the unsatisfactory character of the above 
‘“‘key”’ so far as it relates to the group containing C. spinicauda 
and C. cinereiventris. This results mainly from paucity of material, 
only two specimens of each of the forms designated and only three 
examples of C. cinereiventris lawrence being available for compari- 
son. Of C. cinereiventris pheopygos and what purports to be C. 
fumosa (from western Costa Rica) there are, however, extensive 
series; and in the case of the latter I am convinced that if the birds 
so identified really represent C. fumosa the latter is not a form of 
C. spinicauda, but, on the other hand, is very closely related to and 
almost certainly only subspecifically distinct from C. cinereiventris. 
Indeed I am able to separate it from C. c. cinerewentris (from Brazil) 
only by the much darker color of the under parts, which, however, 
are colored precisely as in C. c. pheopygos, the rump and upper tail- 
coverts being colored exactly as in C. c. cinereiventris, whereas C. 
spinicauda has a very definite pale buffy gray band across the rump 
(instead of a large area of purer or less yellowish gray), very abruptly 
defined against the black of upper tail-coverts, the color of the back 
and pileum being, moreover, sooty blackish instead of glossy bluish 
or greenish black. 
CHZATURA PELAGICA (Linnzus). 
CHIMNEY SWIFT. 
Adults (sexes ahke).—Above plain dark sooty olive, passing into 
paler grayish brown (deep hair brown) on rump, upper tail-coverts, 
and tail, the plumage slightly glossy, the feathers of pileum darker 
centrally, producing an indistinctly squamate effect, those of the 
rump and the upper tail-coverts sometimes very narrowly and indis- 
tinctly tipped with paler; rigid shafts of rectrices black; wings slightly 
glossy sooty blackish, the inner webs of remiges passing into grayish 
brown toward edges; loral region blackish, the feathers along pro- 
jecting edges of forehead and crown (especially the superciliary por- 
tion) narrowly (sometimes very indistinctly or obsoletely) margined 
with whitish; sides of head otherwise, sides of neck, and under parts 
plain grayish brown (nearest dark hair brown, but more grayish), 
fading into a much paler tint (sometimes very pale dull gray or almost 
