180 PEOCEEDINGS OF THE ACADEMY OF [April, 



d^. — Smaller; upper surface darker; lower surface without 

 conspicuous blackish shaft lines, 



Collocalia brevirostris. 

 c^ — Wing less than 124 mm. 



d. — Larger (wing about 121 mm.); upper surface more 

 brownish; rump noticeably paler than back, 



Collocalia fuciphaga elaphra. 



d^. — Smaller (wing 108-118 mm.); upper surface more 



blackish; rump not noticeably paler than back. 



e. — Lower surface paler; upper surface somewhat 



more brownish, Collocalia fuciphaga vestita. 



-•e^ — Lower surface darker; upper surface somewhat 



more blackish, Collocalia fuciphaga fuciphaga. 



B. — Tarsus entirely unfeathered (subgenus Collocalia). 



a. — Abdomen not white in sharp contrast to the breast, the lower 

 surface nearly uniform brownish gray. 

 h. — Rump without a conspicuous white or brownish white 

 band, 

 c. — Feathers of the lores with brownish bases, 



Collocalia leucophaea. 

 c^. — Feathers of the lores with pure white bases. 

 d. — Larger (wing 127-140 mm.). 



e. — Upper surface darker, much more blackish ; lower 



surface darker, and uniform, Collocalia origenis. 



eV — Upper surface lighter, much more brownish; 



lower surface lighter, the throat paler than 



the rest, Collocalia whiteheadi. 



rfi.— Smaller (wing 109.5-123 mm.). 



e. — Upper parts more brownish, more uniform-, the 

 pileum scarcely darker, the rump not lighter, 

 than the back; throat not paler than abdomen. 

 Collocalia unicolor unicolor. 

 e^. — Upper parts less brownish, less uniform, the 

 pileum darker, the rump usually lighter, than 

 the back; throat paler than abdomen, 



Colloccdia unicolor amelis. 

 51. — Rimip with a conspicuous white or brownish white band, 

 c. — Feathers of lores with brownish bases, 



Collocalia thespesia. 

 c^ — Feathers of lores with pure white bases. 

 d. — Smaller (wing 110-114 mm.). 



e. — Abdomen and upper surface darker; light rump 

 band with more conspicuous dark shafts ; size 

 smaller (wing 110-111 mm.), 



Collocalia francica terraereginae. 

 gi. — Abdomen and upper surface paler; light rump 

 band with less conspicuous dark shafts; size 

 larger (wing 112-114), 



Collocalia francica francica. 



