FALCONID J3 — THE FALCONS. 125 
blotched in others, especially in ISf. fuscus. Iris in adult yellow 
to orange. Nest in trees. (Page 134.) 
/3. Form short and heavy, the head larger, the tail shorter, the legs more 
robust. Bill stronger, less compressed, lower through the base, the 
upper outline less ascending basally, and the cere less arched. Com- 
missure variable. 
10. Antenor. Form heavy, the wings and tail moderately long, 
and feet very robust ; bill rather elongated, the commissural lobe 
prominent, and the base of the culmen somewhat depressed. 
Fourth quill longest; outer five with inner webs cut. Lores 
naked, and almost destitute of bristles. Eggs white. Nest on 
bushes. (Page 136.) 
11. Onychotes. Outstretched feet reaching beyond end of tail; 
tibial plumes short, close, not reaching below the joint. Wing 
short, rounded, very concave beneath, the fourth quill longest ; outer 
five with inner webs sinuated. Tail short, but little more than half 
the wing, slightly rounded. Claws very long, and extremely acute. 
Eggs and nesting unknown. (Page 136.) 
12. Asturina. Bill and feet as in Antenor ; lores densely 
bristled ; wing short, rounded, concave beneath, the third to fourth 
quills longest ; outer four with their inner webs cut. Iris brown. 
(Coues). Eggs bluish-white ; nest on trees. (Page 135.) 
13. Buteo. Form of Antenor , but primaries longer and more 
pointed, the fourth usually longest, and the outer three or four with 
inner webs cut. Bill and feet as in Asturina. Tail moderate, or 
rather short, nearly even, or slightly rounded. Iris probably 
brown in young, yellow in adult. Eggs usually blotched ; some- 
times markings of one or more eggs of a set obsolete. Nest 
on trees. (Page 136.) 
Front of the tarsus densely feathered down to the base of the toes. 
14. Archibuteo. Feathering of the tarsus interrupted behind 
by a bare, strip along the full length ; middle toe less than half as 
long as the tarsus. Nostril broadly oval, obliquely horizontal.; 
bill weak, the upper outline of the cere much ascending, basally. 
Feathers of the nape normal, blended. Third to fourth quills 
t longest ; outer four or five with inner webs cut. Iris yellowish- 
gray (Suckley). Eggs and nesting as in Buteo. (Page 139 .) 
15. Aquila. Feathering of the tarsus uninterrupted behind ; mid- 
dle toe more than half as long as the tarsus. Nostril narrowly oval, 
obliquely vertical ; bill strong, the upper outline of the cere nearly 
parallel with the low;er. ' Feathers of the nape lanceolate, distinct. 
, Fourth quill longest ; five to six with inner webs cut. Iris brown. 
Eggs usually thickly blotched, markings occasionally obsolete. 
Nest almost always on cliffs ; exceptionally on trees. (Page 140.) 
** No trace of membrane between outer and middle toes. 
16. Halieetus. Tarsus feathered in front one third, or more, of 
the way down ; the naked portion wifti an imperfectly continuous 
frontal, and less well defined posterior, series of transverse plates, 
and covered elsewhere with roundish granular scales. Feathers-of 
the neck, all round, lanceolate, distinct. Bill very large, the chord 
of the culmen more than twice as long as the cere on top ; nostril 
oval, obliquely vertical. Third to fifth quills longest; outer six 
