a1. Wing less than 115 mm.; sides of lower breast and flanks
chestnut. ... mindorensis (p. 543)
a2. Wing more than 115 mm.; sides of lower breast and flanks not
chestnut.
b1. Chest, head and neck all round nearly uniform broccoli-brown
(slightly darkest on crown).
c1. Wing, about 120 mm.; body uniform blackish; under tail-coverts
longitudinally striped with white.
d1. Larger; length, 225; wing, 121; bill from nostril, 14.7;
body dark brown. ... thomassoni (p. 544)
d2. Smaller; length, 215; wing, 120; bill from nostril, 13;
body practically black. ... mayonensis (p. 544)
c2. Wing less than 120 mm.; body, including tail-coverts and
crissum, uniform clove-brown. ... kelleri (p. 545)
b2. Chest paler, contrasting strongly with the dark color of crown.
c1. Smaller; wing, 124.5 mm.; tail, 96.5; chin, throat, and
chest pale sooty brown, rather lighter on breast, flanks, and
belly; median area of under surface dark, except at vent; under
tail-coverts dark brown with pale, whitish brown tips. ... nigrorum
(p. 545)
c2. Larger; wing, 127 mm.; tail, 115; chin, throat, and chest
pale drab-gray; flanks and breast similar in color to the upper
surface of body; median area of under surface spotted with white
anteriorly, all white posteriorly; under tail-coverts sooty-brown,
with broad, longitudinal white stripes. ... malindangensis (p. 546)