414 PROCEEDINGS OF THE ACADEMY OF 



Not agreeing with Herr Pelzeln's conclusions concerning 31. 

 concentricus (Less.), and M. gilvicollis (Yieill.), Messrs. Sclater 

 and Salvin give to the former the name 31. gilvicollis (Yieill.), and 

 to the latter that of 31. leucauchen (Temra.j, a view of the mat- 

 ter in which we cannot concur, for reasons stated under the head 

 of these species, respectively. 



Ridgway, Robert. Revision of the Falconine Genera, Micras- 

 tur, Geranospiza and Rupornis, and the Strigine Genus Glauci- 

 dinm. Based upon specimens in the Museum of the Smithsonian 

 Institution, the Academy of Natural Sciences of Philadelphia, the 

 American Museum, at New York, the Boston Society of Natural 

 History, the Museum of Comparative Zoology at Cambridge, and 

 the Ornithological Cabinet of Mr. Geo. N. Lawrence. <Proc. 

 Bost. Soc. Nat. Hist., May 21, 1873, pp. 73-106. 



The relationship of this genus to Herpetotheres and the Falcones 

 in osteological structure is here first pointed out, as well as a 

 striking analogy to the Strigidee in the facial ruff, downy edge to 

 inner webs of the primaries, and dimorphic plumage of some 

 species. 



Five species are recognized by the following diagnoses: 



A. Inner toe appreciably shorter than the outer. 



a. Wing, 9.00 or more. 



1. Black above, with a nuchal collar. Tail longer than the wing. 



31. semitorquatus. 



2. Plumbeous above, without a nuchal collar. Tail shorter than 



the wing. 31. mirandollei. 



b. Wing less than 8.00. 



3. Throat and adjoining portions ashy in the adult. No nuchal 



collar. 31. ruficollis. 



4. Throat and crescent behind the jaw white, sharply defined ; 



a nuchal collar of white spots. 31. leucauchen. 



Inner toe appreciably longer than the outer. 



5. Wing less than 8.00. Tail shorter than the wing. Lower tail- 



coverts immaculate white. If. concentricus. 



The references are as follows (omitting 31. semitorquatus and 

 3L mirandollii, which are not different from those given by Sclater 

 and Salvin) : 



3. INIlCHASTUR RUFICOLLIS. (P. 78.) 



Sparvius ruficollis, Vieill. (Rufous phase.) 



Micrastur gilvicollis, Pelz. Orn., Nov. 1865, 10. (Grayish phase.) 



Falco .cunt hothorax, Temm. (Rufous phase.) 



