BIRDS OF NORTH AND MIDDLE AMERICA. 7l7 



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. dnerciventris) . (Grenada, Tobago, Trinidad, and Margarita Island, 



Venezuela.) Chsetura 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.) 



^ Chsetura cinereiventris phaeopygos (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 Trinidad to Venezuela, eastern Peru, and northern Brazil.) 



Chaetura 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 lawrencei being available for compari- 

 son. Of C. cinereiventris flixopygos and what purports to be C. 

 fumosa (from w^estern 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. cinereiventris (from Brazil) 

 only by the much darker color of the under parts, which, however, 

 are colored precisely as in C. c. pliseopygos, the rump and upper tail- 

 coverts being colored exactly as in C. c. cinereiventris, whereas C. 

 spinicauda has a very definite pale bufl"y 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. 



CHAETURA PELAGICA (Linnaeus). 



CHIMNEY SWIFT. 



Adults (sexes alike). — 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 upi)er 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 superciUary por- 

 tion) narrowly (sometimes very indistinctly or obsoletely) margined 

 with whitish; sides of head otlierwise, sides of neck, and under parts 

 plain grayisli brown (nearest dark hair brown, but more grayish), 

 fading into a much paler tint (sometimes very pale dull gray or almost 



