158 FALCONID^. 



Subfamily V. BUTEONIN^. 



Outer toe only connected to middle toe by interdigital membrane ; 

 tibia much longer than tarsus, exceeding it by more than the length 

 of hind claw *. 



Key to the genera f. 



a. Distance between tips of piimaries and tips of 



secondaries equal to or greater than the 

 length of tarsus. 

 «'. Ridge of bill (without cere) less than half 



the length of middle toe (without claw). . 25. UROSPiziAS,p.l59. 



b'. Ridge of bill gi-eater than half length of 



middle toe. 



a". Tail about equal to twice the tarsus ; 



wings reaching up to or beyond the tail. 



a'". Nostrils round, with large tubercular 



process 25*. Heterospizias, 



b'". Nostrils oval, with no tubercular pro- p. IGO. 



cess 26. Tachytriohchis, 



b". Tail longer than twice tarsus ; wings not p. 161. 



reaching to tip of tad. 

 c'". Nostrils long ovals, with no tubercle. 



c*. Tarsus bare 27. Bcteo, p. 164. 



d*. Tarsus feathered to the toes 28. ARCHnJt'XEO, 



d'". Nostrils round, with distinct central p. 195. 



tubercle 29. Buteola, p. 201. 



e'". Nostrils oval, with indistinct and con- 

 cealed tubercle at base of upper margin 30. Asturina, p. 202. 



b. Distance between tips of primaries and se- 



condaries less than length of tarsus. 

 c'. No perceptible crest. 



* I have clone my utmost to secure the exact relative dimensions of these two 

 bones ; but the scantiness of osteologieal material renders positive identification 

 in many cases impossible. At any rate the probability that some genera placed 

 by me among the Buteonince may some day be found to belong to the ji^ccipitrinae 

 only proves the truth of Professor Sundevall's remark that the two subfamilies, 

 are hardly separable (Av. Tent. p. 107). 



t One genus remains still unknown to me, Onychotes of Eidgway (Pr. Phil. 

 Acad. 1870, p. 142) :— 



" Nostril nearly circular, with a conspicuous (not central) tubercle. Tarsus 

 very long and slender ; toes moderate ; claws very long, strong, and sharp, but 

 only sUghtly curved. Tibial feathers short, close, not reaching below the joint. 

 Wing very short, much rounded and very concave beneath; 4th quill longest, 

 1st shorter than 9th. Tail moderate, rounded." 



Type O. grueheri, Eidgway, /. c. 



Hah. CaHfomia [?]. 



Mr. Eidgway has privately communicated to me the following additional 

 details in answer to my inquiries : — " The posterior face of the tarsus has a row 

 of transverse scutellae, as in Buteo. The tarsus is longer than the distance from 

 the ends of the secondaries to the tip of the primaries. The tips of the pri- 

 maries reach to about the middle of the tail, which, however, is comparatively 

 short; they fall short of the end of the tail by about the length of the tarsus. 

 The nostrils are nearly round ; they are not overhimg by any perceptible mem- 

 brane, though the upper part of the nasal aperture is filled by the tumid skin of 

 the cere, much as in Buteo &c. The soles of the feet are as in Buteo. The 

 distance from ends of secondaries to tips of primaries is 2-,")0 inches. Length 

 of tarsus 2-70 inches, middle toe r45, hind toe 080." 



From a comparison of these details with the above table it will be seen that 

 Onychotes is closely allied to. if not identical with, Urubitinga. 



