Ridgivay — American Families of Oligomyodian Passeres. 15 



12. Culicivora Swainson. 

 (Type, Muscicapa stenura Temminck.) 



The tarsal envelope of this genus appears on first sight to be exaspidean ; 

 but, while the acrotarf^ium entirely crosses the outer side of the tarsus and 

 occupies the greater part of the inner side, there is interposed between the 

 two edges a continuous series of very distinct lozenge-shaped scutella. The 

 style of coloration (conspicuously streaked above) is very different from 

 that of any true Tyrannine form and recalls that of some Synallaxinee 

 (Furnariidae) or some of the smaller Formicariidse. 



PlPRID^. 



The diagnosis of this group as given l\v Dr. Sclater requires 

 no modification, all possessing an exaspidean tarsal envelope, 

 like the Tyrannidse, l)ut differing from the latter in having the 

 second phalanx of the middle toe at least half (usually wholly) 

 united to the outer toe or else (in the genus Pijmtes only) hav- 

 ing the first phalanx of the middle toe wholly coherent with the 

 inner toe. Ntn^rtheless the characters of the group necessitate 

 the exclusion of one genus {Ptilochloris* Swainson) and its trans- 

 fer to the Cotingidse, and the addition (a substraction from 

 Cotingidse) of another (genus AuUa Bonaparte). 



COTINGID.E. 



The Cotingidae are characterized by Dr. Sclater (Cat. Birds 

 Brit. Mus., xiv, 1888, 2) as Oligomyodian l)irds with pycnas- 

 pidean tarsi — no other character for the group l)eing given. 

 Nevertheless, as a matter of fact, a consideraljle number of the 

 genera belonging to the group as limited by Dr. Sclater have not 

 pycnaspidean tarsi, though it is equally true that none of them 

 have the tarsal envelope exaspidean. The group is an exceed- 

 ingly complex one, and I have very strong doubts as to its 

 homogeneity. Rvpicola I certainly would exclude as a separate 

 family, Rupicolidae ; and I believe that when more is known of 

 their internal structure disintegration of the group will go farther. 



So far as external characters are concerned, I am able to 

 diagnose the Cotingidse, as a separate group from the Tyrannidae 

 and Pipridse, only by their different (non-exaspidean) tarsal 

 envelope ; but if the group were limited to those forms possess- 

 ing pycnaspidean tarsi it would be very much more restricted 



* I am using the names adopted by Dr. Sclater, it being unnecessary to discuss here 

 whether Laniimma Swainson and Lanioceia Lesson should not displace Plilochloris and 

 AiiUa respectively. 



