Mr. R. B. Sharpe's Catalogue of Accipitres. 235 



Mr. Sliarpe does not mention in his account of Buteo 

 swainsoni the difference in coloration which exists between 

 the adult male and female in their normal state of plumage. 

 This difference is thus summarized by Mr. Ridgway, in his 

 paper on the Subgenus Craxirex, to which I have already 

 referred : — 



'' $ . Breast-patch rufous, with darker shaft-streaks ; 

 ? . Breast-patch dark greyish-umber or blackish-brown 

 (like the back) ," 



According to the measurements of this species given by 

 Mr, Ridgway, a very remarkable disparity exists in the 

 dimensions of different individuals of the same sex, especially 

 in the length of the Aving from the carpal joint to the tip of 

 the primaries. In twenty-two adult males whose dimensions 

 are given by Mr. Rid g way, the length of this measurement 

 of the wing varies from 12 inches to 16, and in thirty adult 

 females from 14-75 to 17'25. Having regard to these differ- 

 ences, it seems to me probable that the investigations of Ame- 

 rican ornithologists will ultimately result in the discrimi- 

 nation of two distinct races, a larger and a smaller, both at 

 present referred to Buteo swainsoni, but not in reality iden- 

 tical, in which case the smaller race will, I think, be entitled 

 to the name of Buteo futiginosus , Sclater. 



I may here mention that I have recently remeasured the 

 type specimen of Buteo fuliginosus in the Norwich Museum, 

 and make the wing 12*6, and the tarsus 2"05, both these 

 measurements being slightly different from those given in the 

 original description of this specimen (P. Z. S. 1858, p. 356). 



Mr. Sharpe speaks of the melanistic phase of Buteo swain- 

 soni as being "^ fully adult;" but if this means that every 

 individual which lives to be " fully adult " attains this state 

 of plumage, it is a statement in which I cannot concur. It 

 may possibly be correct as regards the smaller race, which I 

 am disposed to look upon as separable under the title of B. 

 fuliginosus ; but in the larger and commoner form, to which 

 I would restrict the name of B. swainsoni, melanistic speci- 

 mens are comparatively so rare that in my opinion they can 

 only be looked upon as accidental. 



R 2 



