470 Mr. J. II. Gurney's Notes on 



naturally separated by the totally different character of their 

 immature plumage — the one group, to which I would restrict 

 the title of Urubitinga, consisting of U. zonura, U. anthra- 

 cina, and U. gundlachi (if the latter be really distinct), and 

 the other, for which I would retain the name of Leucopternis , 

 consisting of the remaining species included by Mr. Sharpe 

 in his amalgamated genus*. 



Leaving the restricted genus Urubitinga for future consi- 

 deration, I now propose to make a few remarks on some 

 species of the genus Leucopternis, based upon specimens in 

 the Norwich Museum^ and upon others very kindly lent to 

 me by Messrs. Salvin and Godman. 



Commencing with that beautiful species, L. ghiesbreghti, I 

 may observe that the proportion of black Avhich mingles with 

 the snowy white of its general plumage is greatest in young 

 birds, and appears gradually to diminish as their age in- 

 creases. 



The specimen described by Mr. Sharpe as " adult " appears 

 to me to retain a greater proportion of black in its plumage 

 than is the case in some still older specimens ; a very adult 

 female in the collection of Messrs. Salvin and Godman differs 

 from Mr. Sharpens description in the following particulars : 

 the greater wing-covei*ts are entirely white, and the primary- 

 coverts are broadly tipped with white; the primaries are 

 white above the emargination, as are the secondaries through- 

 out, with the exception of a very few sparse and irregular 

 remnants of black here and there. 



The specimen figured and described by Du Bus (Esquisses 

 Ornithologiques, pi. 1) appears also to be more completely 

 adult than that described by Mr. Sharpe. 



As Mr. Sharpe does not mention the first plumage of this 

 species, I may add that a decidedly immature example in the 



* Mr. Ridgway, in his recently published and very valuable ' Studies 

 of the American Falconidce,' whilst recognizing the distinction between 

 the genera Urubitinga and Leucopternis, includes in the former, at p. 172, 

 two species (schistacea absolutely, and j)lumhea conjecturaUy) which I, 

 following Mr. Salvin (Ibis, 1872, p. 243), refer to Leucopternis, having no 

 evidence that either of them exhibits when young the remarkable imma- 

 ture plumage which is characteristic of Uruhttinga as distinguished from 

 Leucopternis. 



