Ridgway on a Tropical American Hawk. 209 



Guatemala which appears to me to be identical with the type of 

 Buteo fnliginosus preserved at Norwich. This specimen agrees 

 in dimensions with the female of B . brachyura but (like the type 

 specimen of B. fnliginosus) is dark brown rather than black 

 and has scarcely any white on the forehead, the type specimen 

 having absolutely none. 



" Mr. Salvin and myself are now of opinion that these are 

 only individual variations (seeing that the dimensions and form 

 of the primaries agree) and that therefore Buteo fnliginosus 

 should sink into a synonym of Buteola brachyura and should not 

 be considered as a melanism of Buteo swaiusoni." 



That this black form, for which Buteo fnliginosus appears to 

 be the earliest name, is unquestionably referable to B. brachyurus 

 does not, however, appear to be so easily demonstrable ; at least 

 none of the authors whom I have been able to consult give suf- 

 ficient reasons for taking this view of its status. I have examined 

 altogether eleven examples of B. fnliginosus and four of normal 

 B. brachyurus, the latter all adults, the former including both 

 adults and young. Not one of the former indicated in the 

 slightest degree, by any variation from the tvpical plumage, the 

 probability of intergradation with true B. brachyurus, which, 

 considering the number of specimens, seems strange if they were 

 really the same species. It is a well-known fact that in the case 

 of all the other North American Buteones which have a well- 

 marked melanistic phase {e.g. Buteo borealis, B. sxvainsoni, 

 and Archibuteo lagopus sancti-johannis), examples wholly 

 black in plumage are comparatively rare, or altogether less 

 numerous than those which simply tend toward this condition, 

 the light normal and the completely melanistic extremes of plu- 

 mage being connected by an unbroken series of variously inter- 

 mediate specimens. In the eleven specimens of B. fnliginosus, 

 however, we observe exactly the same uniformity of characters 

 as in B. abbreviatus — a species which, so far as known, has 

 no light-colored phase, while the differences distinguishing the 

 young and old are exactly the same as in that species ! The four 

 adult specimens of B. brachyurus are likewise very much alike, 

 and I have never heard of any specimens of this species, except 

 young birds, which possessed a mixed lower plumage. Taking 

 these facts alone as my guide, I should not think of uniting the 

 two forms, but assuming that Messrs. Gurnev and Salvin, having 



