I 
1 Q A 
lo4 
. Genus ONYCHOTES, Eidgway. 
■Onycholes , Ridgway, Pr. Acad. Nat. Sci. Philad. Dec. 1870,142; type, O. gru-beri, nov. sp.— 
Ridgw. B. B. & R. Hist. N. Am. Birds, iii, 1874, 252 (outlines of generic 
characters). 
Characters. —General form and size most similar to that of species 
of Rupornis and Asturina. Bill very short, the tip unusually 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. Nostril nearly circular, 
or properly 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 phalangeal articulation of the middle toe; hind foe shorter 
than the inner. Scutellation of the tarsi and toes as in the typical 
Buteones , 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, which 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. Remiges, 24; 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 Fdl- 
conidw , nor, indeed, among those of the Old World; and the several striking 
peculiarities of detail iu 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 Buteones of tropical America; it agreeing 
very nearly in size with “ Buteola v minuta and B. brachyura. 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 u Buteo 
fuliginosus Sclater n ; 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 Rostrhamus , in which, however, the feet are much weaker, 
and the tarsus conspicuously shorter, while otherwise the bird is ex¬ 
tremely different. 
