Breeding female from Cebu.--Bill horn-blue; cere waxy green; iris and eyelids chrome-yellow; legs greenish yellow; nails blackish. Length, 312; wing, 179; tail, 136; culmen from base, 20; tarsus, 56; middle toe with claw, 44. Immature male.--Upper parts earthy brown; head and mantle slightly bluish ash; feathers of wings, mantle, rump, and upper tail-coverts edged with rusty brown; median line on throat incomplete; breast and abdomen white with very wide, seal-brown, shaft-stripes; sides and flanks with some reddish brown cross-bars; thighs white, barred with brown; wing-lining ochraceous with large blackish brown spots. "Accipiter manillensis is, I think, subspecifically distinct from typical A. virgatus, and Mr. Whitehead having, in addition to the Museum series, now obtained three adult females, we have a fair number of skins for comparison. "Adult female.--Differs from the female of A. virgatus in having the chest, breast, and sides nearly uniform light red in the most adult birds, while in somewhat younger examples the middle of the breast shows distinct cross-bars of reddish brown and white; the under surface on the quills washed with rufous. Wing, 175 to 178; tail, 137 to 139; tarsus, 52 to 53. "Adult male.--Like the male of A. virgatus. Wing, 152 to 155; tail, 122 to 124; tarsus, 51." Grant, Ibis, (1896), 109. I have found considerable difficulty in identifying members of the genus Accipiter from the Philippines and the preceding descriptions will require revision when more specimens shall have been collected. With some hesitation I have placed A. stephensoni as a synonym under A. manillensis instead of under A. gularis. Subfamily AQUILINÆ. Genera. a1. Tail nearly square or slightly forked; or, if decidedly graduated, the wing over 350 mm. b1. Bill without a distinct tooth on its cutting edge; first primary much shorter than second or third. c1. Feathers of lores and circumocular region not scale-like; loral bristles present. d1. Tail not forked. e1. Tarsus covered to the toes with short thick-set feathers. f1. Distance between tips of primaries and secondaries much greater than length of tarsus. ... Lophotriorchia (p. 223) f2. Distance between tips of primaries and secondaries much less than length of tarsus. ... Spizaëtus (p. 224) e2. Tarsus not feathered to the toes. f1. Nostril a vertical slit; bill extremely compressed; culmen curved throughout its length; size large. ... Pithecophaga (p. 226) f2. Nostril round or oval; bill not greatly compressed. g1. A full, circular, occipital crest; plumage of under parts with numerous round white spots. ... Spilornis (p. 227) g2. Crest scanty or wanting; plumage not spotted. h1. Back of tarsus covered with hexagonal scales; wing, 330 to 380 mm.