222 MANUAL OF PHILIPPINE BIRDS. 



Subfamily AQUILINE. 

 Genera. 



a 1 . Tail nearly square or slightly forked ; or, if decidedly graduated, the wing over 



350 mm. 

 6 1 . Bill without a distinct tooth on its cutting edge ; first primary much shorter 



than second or third. 

 c l . Feathers of lores and circumocular region not scale-like; loral bristles 



present. 

 <P. Tail not forked. 



e l . Tarsus covered to the toes with short thick-set feathers. 



f 1 . Distance between tips of primaries and secondaries much greater 



than length of tarsus Lophotriorchis (p. 223) 



f 1 . Distance between tips of primaries and secondaries much less than 



length of tarsus Spizactus (p. 224) 



e 2 . Tarsus not feathered to the toes. 



f 1 . Nostril a vertical slit; bill extremely compressed; culmen curved 



throughout its length; size large Pithecophaga (p. 226) 



f 3 . Nostril round or oval; bill not greatly compressed. 



g l . A full, circular, occipital crest; plumage of under parts with 



numerous round white spots Spilornis (p. 227) 



g-. Crest scanty or wanting; plumage not spotted. 



h l . Back of tarsus covered with hexagonal scales; wing, 330 to 380 



mm. 



i 1 . Tarsus with hexagonal scales in front; wing falling far short 

 of tip of tail; lower plumage whitish, barred or spotted 



with brown Butastur (p. 230) 



t 1 . Tarsus with transverse scutes in front; wing very long, 

 extending beyond end of tail ; plumage chestnut and white 



in adult Haliastur (p. 233) 



k*. Back of tarsus with large transverse plates; wing over 500 mm. 



Haliaeetns (p. 232) 



d 2 . Tail slightly forked, middle feathers about 10 mm. shorter than outer- 

 most; unfeathered portion of tarsus covered with small round scales. 



Elanns (p. 234) 



c 2 . Feathers of lores and large circumocular area short and scale-like; no hairs 

 about the bill; tarsus covered with long feathers for more than half its 

 length, unfeathered portion with small hexagonal scales on all sides. 



Pcrnis (p. 236) 



6 a . Bill with one or two well-developed teeth on its cutting edge; first primary 

 nearly as long as second and usually longer than third. 



c 1 . Head crested; tarsus feathered for half its length Baza (p. 236) 



c-. Head not crested ; tarsus feathered at base only and covered with hexagonal 

 scales. 



d 1 . No tubercle in nostril ; length less than 200 mm Microhierax (p. 238) 



d 3 . A tubercle in center of nostril ; length more than 250 mm.. Falco (p. 239) 

 a 2 . Tail distinctly graduated; bill shorter; feet smaller and weaker; middle toe 

 without claw two-thirds to three-fourths of tarsus ; wing less than^SO mm. 



Cerchneis (p. 243) 



