.426 BIKDS OF ILLINOIS. 



SuBORDKH FAIiCONES.— Diurnal Eaptores. 



Familt FAliCONID-ffi. — Falcons, Kites, Hareiers, Hawks, and 

 Eagles. 



Chab. Eyes directed laterally, and eyelids provided with lashes. Toes invariahly 

 naked, and tareus usually naked and scutellate (feathered only in -44ui;a ajidArdiibuteo). 

 Outer toe not reversible (except in Pandion). Head never with ear-tults, and never 

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



The above characters are about the only readily observable points 

 in the external anatomy in which the Falcones differ strikingly 

 from the Striges and Sarcorhamphi, 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 taxonomic point of view, and serve to separate the Diurnal Eap- 

 tores as a well-defined suborder. 



The number of subfamilies 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 being a small oriflee. with 

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

 Polyborus) linear and oblique, with its upper end the posterior one. Scapu- 

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

 Inferior surface of the supramaxillary bone with a prominent median angular 

 ridge. Superciliary process of the lachrymal consisting of a single piece. Falconince. 



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

 oval, opening, of oblique direction, its lower end being invariably the pos- 

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

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

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

 bony rim or tubercle. Interior surface of the supramaxillary bone without 

 a median ridge. Superciliary process of the lachrymal vari.able. 



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

 width on under surface. Plumage with aftershafts Accipitrince. 



b. Outer toe reversible. Claws aU of equal length, and narrowed and 

 rounded on their under surface. Plumage without aftershafts Pandionince. 



