THE IBIS. 



THIRD SERIES. 



No. XXI. JANUARY 1876. 



I. — Second Thoughts on the Genus Micrastur. By Robert 

 RiDGWAY, of the Ornithological Department, U.S. National 

 Museum, Washington. 



Having recently examined the entire series of the smaller 

 members of this genus contained in the collection of Messrs. 

 Salvin and Godman, sent to me for that purpose, I have been 

 induced to modify to some extent my views given in the 

 ' Proceedings ' of the Boston Society of Natural History for 

 1873. 



The series is a splendid one, and has, I think, enabled me 

 to get the right idea of the species of this exceedingly per- 

 plexing group. 



Setting M. melanoleucus (sive " semitorquatus") and M. 

 mirandoUii aside, as being distinct enough to need no notice 

 in connexion with the smaller species, I identify the names 

 of previous authors as follows : — 



Sparvius ruJicollis,Yie\\\., = M. ruficolJis, Scl. & Salv., rufous 

 phase, adult. 



Sparvius gilvicollis, Vieill.*,=M. leucauchen, Scl. & Salv., 



* This cannot, according to ' the terms of the diagnosis, be M. gilvi- 

 collis, Scl. & Salv., if the latter = my concentriciis, which = concentricus of 

 SER. III. VOL. VI. B 



