322 On the Affinities of the Falconida. 



and well marked tooth in the upper mandible, and cor- 

 responding to which there was a notch in the under, which 

 is wanting in all the Falconidae, which are only provided 

 with a festoon. But the principal characters in which this 

 genus differs from the genus Falco, is in the form of the 

 tarsus, and in the wings not extending further than the 

 upper third of the tail.* In the Kestrels, and in its nu- 

 merous allied species, we have not only the wings consider- 

 ably shorter than the tail, but also the tarsi in part scu- 

 tellated, which is particularly the case with the Falco Cer- 

 chnis, Sparverius of America, forming a connecting link 

 between the preceding genus and the genus Hierax, which 

 presents the following characters : — Bill short, curved from 

 the base, compressed, but convex laterally, cutting edge of 

 upper mandible furnished with a prominent tooth, anterior 

 to which there is a deep groove ;f cutting edge of under 

 mandible notched and truncated perpendicularly at the tip ; 

 gape not extending as far as the anterior angle of the eye. 

 Nostrils rounded and inserted into the lateral and anterior 

 part of the cere which is very narrow above, and gradually 

 increases towards its base, and is partially covered with 

 feathers. Wings rather short and pointed; second and 

 third quill feathers equal, and longest ; first nearly equal to 

 the second and third ; fourth nearly equal to the first ; fifth 

 much shorter than the fourth. Tarsus robust, rather long 

 and scutellated, upper third feathered anteriorly. Toes very 

 low and scutellated, the middle one being much the longest, 



* Lesson, without assigning any reason, arranges the Falco laniarius 

 along with the Falco islandicus in the genus Hierofalco ; its proper place, 

 however, as well as that of the Falco borigora, of which he is doubtful, 

 is in the genus Falco, as we have characterised it. See Lesson Traite 

 D' Ornithologie, p. 97. 



f By many authors the species which is the type of this genus has 

 been described as double toothed, which is not the case if properly 

 examined. 



