222 MANUAL OF PHILIPPINE BIRDS. 



Subfamily AQUILIN.^. 



Genera. 



«\ Tail nearly square or slightly forked; or, if decidedly graduated, the wing over 

 350 mm. 

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

 than second or third, 

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

 present. 

 d\ Tail not forked. 



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



p. Distance between tips of primaries and secondaries much greater 



than length of tarsus Lophotriorchis (p. 223) 



/-. Distance between tips of primaries and secondaries much less than 



length of tarsus Spizaetus (p. 224) 



e". Tarsus not feathered to the toes. 



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



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



/^ Nostril round or oval: bill not greatly compressed. 



g\ A fiill. circular, occii)ital crest ; plumage of under parts with 



numerous roimd white spots Spilornis (p. 227) 



(f-. Crest scanty or wanting; plumage not spotted. 



//'. Back of tarsus covered with hexagonal scales; wing, 330 to 380 

 nun. 

 ('. Tar.^us with hexagonal scales in front; wing falling far short 

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



with brown Butastur (p. 230) 



I-'. Tarsus with transverse scutes in front ; wing very long, 

 extending beyond end of tail ; plumage chestnut and white 



in adult Haliastur (p. 233) 



/(-'. Back of tarsus with large transverse plates; wing over 500 mm. 



Haliaeetus (p. 232) 

 <P. Tail slightly forked, middle feathers about 10 mm. shorter than outer- 

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



Elanus (p. 234) 

 <f. 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, unfeatliered portion with small hexagonal scales on all sides. 



Pernis (p. 235) 

 6^ 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'. Head crested; tar-sus feathered for half its length., Baza (p. 236) 



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

 scales. 



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



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

 ft-. Tail distinctly graduated; bill shorter; feet smaller and weaker; middle toe 

 without claw two-thirds to three-fourths of tarsus; wing less than 250 mm. 



Cerchneis (p. 243) 



