Mr. R. B. Sharpens Catalogue of Accipitres. 445 



Hodgson's specific .name of F. milvipeSy of which Mr. Hume's 

 subsequent one of F. hendersoni (founded on the specimen 

 figured in ' Lahore to Yarkand ') is a synonym. This is a 

 point as to which I can speak with certainty, as the type 

 specimens of '^ Falco milvipes " and " Falco hendersoni " 

 are both preserved in the British Museum, where I compared 

 them very carefully in 1875, and again a few weeks since. 

 I find them identical, with some very slight exceptions, 

 arising, as I consider, from the type of Falco hendersoni 

 being rather the older bird, and also more recently moulted. 

 Both appear to be male birds*, and differ very little in their 

 dimensions. 



Whether G. milvipes is really specifically distinct from G. 

 saker, or whether, as held by Mr. Sharpe, and as, on the 

 whole, seems to me more probable, it is merely G. saker in 

 its oldest stage of plumage, must, I think, for the present 

 remain an open question. 



The arguments in favour of the specific identity of G. mil- 

 vipes and G. saker are very ably stated by Mr. Dresser in 

 his article on vFa/co sacer, in the 'Birds of Europe,' vol. vi. 

 p. 59 ; and it is unquestionable that the specimens preserved 

 in the British and Norwich Museums appear to present a 

 series of progressive changes of plumage from the ordinary 

 immature dress of F. saker to the type specimen of Mr. 

 Hume's Falco hendersoni, which is certainly the most perfect 

 example of the G. milvipes phase of plumage that has come 

 under my notice. 



On the other hand, we have the strong opinion of Mr. 

 Hume, founded on his very extensive observation of Saker 

 Falcons in Northern India, in favour of the distinctness of 

 the two supposed species ; and this view is strengthened by 

 the Mongolian experience of Col. Prjevalsky, who writes thus 

 in the article to which I have already referred, — '^ In the 

 region of our travels we did not observe, or at least did not 



obtain, the true Falco sacer, Schl Everywhere we 



found only the species described by Hume, in ' Lahore to 



* The male sox of the typo of "■Falco hendersoni " was ascertained by 

 dissection ; vide ' Lahore to Yarkand," p. 171. 



SER. IV, VOL. VI. 2 H 



