134 



Genus ONYCHOTES, Ridgway. 



'Onycliotes, Eidgway, Pr. Acad. Nat. Sci. Pbilad. Dec. 1870, 142; type, 0. gruherl, nov. sp. — 

 EiDGW. B. B. & E. Hist. N. Am. Birds, iii, 1874, 252 (outlines of generic 

 characters). 



Chaeacters. — General form and size most similar to that of species 

 of Riqwrnls and Asturina. Bill very short, the tip nuusnally obtuse ; 

 cere very large and broad on top, its length almost equal to the chord 

 of the culmen, and its greatest breadth equal to its length. Superior 

 tomium slightly lobed ; gonys slightly convex. Kostril nearly circular, 

 or i^roperly semi-circular or broadly ovate, its upper outline being less 

 curved than the lower, more horizontal, its direction nearly parallel with 

 the commissure of the bill ', a cartilaginous tubercle is seen within the 

 nostril in its upper portion. Outstretched feet reaching to or beyond 

 end of the tail; tarsus long and slender, nearly twice the length of the 

 middle toe ; outer toe decidedly longer than the inner, which reaches 

 the second jDhalangeal articulation of the middle toe; hind toe shorter 

 than the inner. Scutellation of the tarsi and toes as in the typical 

 Biiteones, there being a continuous single series of transverse plates on 

 the posterior face of the former: those on the anterior face number 

 11-12. Claws proportionally large, those of the first and second toes 

 considerably exceeding their digits in length ; they are much graduated 

 in size to the outer, wliich is only half the length of the posterior one; 

 their shape is normally buteonine. A well-developed web between outer 

 and middle toes. Wing short and much rounded, reaching to about the 

 middle of the tail, which is slightly rounded, and more than half as long 

 as the wing. Eemiges, 21; rectrices, 12. Third, fourth, and fifth quills 

 longest, and nearly equal; first shortest; second about equal to sixth; 

 outer five with inner webs emarginated. Plumage generally dense and 

 rather compact; tibial plumes short, reaching but little below the joint; 

 upper third of the tarsus densely feathered in front and on sides. Lores 

 quite densely covered with strong black bristles, these extending forward 

 so as to cover the entire cere beneath the nostrils. Superciliary shield 

 bare and prominent. 



This buteonine form has no very near relative among the American Fal- 

 (?o?iiV7fc, nor, indeed, among those of the Old World ; and the several striking 

 lieculiarities of detail in its external structure, besides the existing un- 

 certainty regarding its precise habitat, and the unknown history of the 

 only two specimens known to exist in collections, render this bird one 

 of extreme interest. The general aspect of this peculiar hawk is that of 

 the smaller short-winged .Bufeones of tropical America ; it agreeing 

 very nearly in size with " Buteola " minuta and B. hrachyura. The fuligi- 

 nous plumage resembles also that of several species of the genus Buteo, 

 so much so, in fact, that the original specimen was labeled '■'■Buteo 

 fuliginosiis Sclnter " ; while in the normal, or lighter phase, there is a 

 somewhat close resemblance to the plumage of the latter of the two 

 species above mentioned. There are very many striking peculiarities of 

 external structure, however, which mark it as one of the most strongly- 

 characterized genera in the group to which it belongs, notably the 

 densely-bristled lores and lower jaw, the broad, high cere, short, obtuse 

 bill, and very long claws. In the latter feature, there is a close approach 

 to the genus BostrJunmis, in which, however, the feet are much weaker, 

 and the tarsus conspicuously shorter, while otherwise the bird is ex- 

 tremely different. 



