Hind toe directed backward and only partially reversible; tail
short, square or but slightly forked; shafts of rectrices normal,
not extending beyond the webs. This genus includes numerous small
swifts, several of which build the edible nests of commerce.
Species.
a1. Larger; wing, 115 mm. or more; under parts brown; no white
on abdomen.
b1. Without whitish or grayish band across rump.
c1. Tail square; tarsi unfeathered. ... lowi (p. 352)
c2. Tail slightly forked.
d1. Tarsi entirely devoid of feathers.
e1. Above lighter and more brownish; below lighter, throat
paler. ... whiteheadi (p. 353)
e2. Above darker, and more blackish; below darker and more
uniform. ... origenis (p. 353)
d2. Tarsi sparsely feathered. ... fuciphaga (p. 354)
b2. A whitish or grayish band across rump. ... germani (p. 355)
a2. Smaller; wing, 106 mm. or less; lower parts mottled with white;
middle of belly extensively white.
b1. A white band across the rump. ... troglodytes (p. 355)
b2. Without white band on rump.
c1. Upper tail-coverts margined with white. ... marginata (p. 356)
c2. Upper tail-coverts concolorous with back. ... isonota (p. 357)