222 MANUAL OF PHILIPPINE BIRDS. 
Subfamily AQUILIN 4&. 
or: 
a, Tail nearly square or slightly forked; or, if decidedly graduated, the wing over 
350 mm. 
bt. Bill without a distinct tooth on its cutting edge; first primary much shorter 
than second or third. 
c. Feathers of lores and cireumocular region not scale-like; loral bristles 
present. 
d', Tail not forked. 
e’. Tarsus covered to the toes with short thick-set feathers. 
f'. Distance between tips of primaries and secondaries much greater 
Ghamelenp thy Ob Gans ustese eee eee eee Lophotriorchis (p. 223) 
f°. Distance between tips of primaries and secondaries much less than 
lengthioftarsuseei:t::t05 0) 2 ee eee a oe Spizaétus (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) 
f?. Nostril round or oval; bill not greatly compressed. 
g. A full, cireular, occipital crest; plumage of under parts with 
numerous round white spots..................------ Spilornis (p. 227) 
g°. Crest scanty or wanting; plumage not spotted. 
’. Back of tarsus covered with hexagonal scales; wing, 330 to 380 
mm. 
i. Tarsus with hexagonal scales in front; wing falling far short 
of tip of tail; lower plumage whitish, barred or spotted 
Watt DrOWM pes tecs.--cc6 bs 3-brey Soe eee Be Butastur (p. 230) 
i?, Tarsus with transverse scutes in front; wing very long, 
extending beyond end of tail; plumage chestnut and white 
AT Se UU, eee UN ee ee Haliastur (p. 233) 
h*. Back of tarsus with large transverse plates; wing over 500 mm. 
Halizetus (p. 232) 
d. Tail slightly forked, middle feathers about 10 mm. shorter than outer- 
most; unfeathered portion of tarsus covered with small round scales. 
Elanus (p. 234) 
c*. 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. 
Pernis (p. 235) 
b*. 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; tarsus 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. 258) 
d*, A tubercle in center of nostril; length more than 250 mm.. Falco (p. 239) 
a*. 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. 245 
