426 BIRDS OF ILLINOIS. 



Suborder FALCONES. — Diurnal IUptores. 



Family FALCONID^ffi. — Falcons, Kites, IIariueus, Hawks, and 



Eagles. 



Chab. Eyos directed laterally, and eyelids provided with lasheg. Toes Invariably 

 naked. and tarsus usually naked and seutellate (feathered only in Ai/iiHn and Arrhihuleo). 

 Outer toe not reversible (oxeeiit in J'aiiilioii). Head never with ear-tufis, and never 

 wholly naked (except in the Vulturinir. of the Old World). 



The above characters are about the only readily observable points 

 in the external anatomy in which the Falcoiu-s differ strikingly 

 from the Striijeit and Sarrorhainphi, and may serve to distinguish 

 the birds of this family from those of the two others. The osteo- 

 logical characters, however, are more decided and important from 

 a taxonomie point of view, and serve to separate the Diurnal Rap- 

 tores as a well-defined suborder. 



The number of subfamihes into which the family is divisible is an 

 open question. In North America, however, the following may be 

 distinguished : 



A. Nasal bones almost completely ossified, the nostril bcini; a small orifice, with 

 a conspicuous central bony tubercle: its form nearly or quite circular, or (in 

 Poluhorus) linear and obliiiue, with its upper end the posterior one. Scapu- 

 lar process of the coraeold produced forward so as to meet the clavicle. 

 Inferior surface of the supramaxlllary bone with n prominent median angular 

 ridge. Suporeiliary process of the lachrymal consisting of a single piece, fa /roniiin'. 



B. Nasal bones very incompletely ossified, the nostril being a large, more or loss 

 nval, opening. of oblioue direction, its lower end being invariably the pos- 

 terior one; without bony tubercle, and never perfectly circular. "Scapular 

 process of the coraeold not produced forward so as to meet the clavicle. 

 Nasal bones incompletely ossified, the nostrils being very large, and without 

 bony rim or tubercle. Inferior surface of the suprama.xillary bone without 

 n median ridge. Superciliary process of the lachrymal variable. 



a. Outer toe not reversible. Claws of unequal length, and not ooutrneted in 



width on under surface. Plumage with aftershafts Accipilrin(r. 



h. Outer too reversible. Claws all of equal length, and narrowed and 



rounded on their under surface. Plumage without aftershafts Pandionina. 



