338 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



now referred to the Cotingidse solely on account of the different 

 character of the tarsal envelope." 



In order to get as clear an understanding as practicable of the classi- 

 fication of the group, all the genera available^ to me have been 

 carefully compared. jSlany days were devoted to an attempt to 

 construct a "key" to all the genera in hand, but it finally became 

 evident that the task would require far more time for its completion 

 than could be allowed, and therefore it became necessary to restrict 

 the key to those genera belonging to the geographic field of the 

 present work, together with a few extralimital ones included for 

 the purpose of comparison. Even with this elimination of half the 

 genera the task has proven exceedingly difficult and the results far 

 from satisfactory, although it is believed that some improvement 

 has been made over the "purely provisional" arrangement in the 

 "Catalogue of Birds in the British Museum,"'^ in which the so-called 

 subfamilies are without question purely artificial and the allocation 

 of certain genera obviousl}- ^^Tong.'^ The subject has called forth a 

 very pertinent and interesting paper from Doctor von Ihering,^ in 

 which a partial reconstruction of Doctor Sclater's "Subfamilies," 

 based chiefly on biological facts, is shoAvn to be necessary, the pro- 

 posed changes being as follows: 



(1) The Tseniopterina^ restricted by elimination of the genera 

 Sayornis, Sisopijgis, and, probably, Machetornis. 



(2) The Platyrhynchinffi divided into two grou])s, Ii^uscarthmina^ 

 and Serpophaginse. 



a The general Lathria, Lipangus, Attila, Hylonax, Sirystes, Idiotriccus, Tyrannulus, 

 Microtriccus, etc. It is true that the Cotingidaj are supposed to be catacromyodous, 

 that is, have the vocal muscles inserted on the ventral instead of the dorsal end of the 

 bronchial semirings; but it is equally true that there are many genera (including those 

 just mentioned) in both the Tyrannidse and Cotingidse, as now understood, of which 

 the character of the insertion of the vocal muscles is unknown. (See remarks under 

 Mesomyodi, on p. 329.) 



b The only genera not examined are the following: Ochlhornis Sclater, Ceratotriccus 

 Cabanis, Pseiidotrkcus Taczanowski and Berlepsch, Leptotriccus Cabanis and Heine, 

 Pseiidomyobius Salvadori and Festa, Planchesia Bonaparte, Taeniotriccus Berlepsch 

 and Hartert, Phaeomyias Berlepsch, and Acrochordopus Berlepsch and Hellmayr. 



c Catalogue ] of the | Passeriforfnes, ] or | Perching Birds, ] in the | collection | of 

 the 1 British Museum. | Oligomyodse, | or the Families | Tyrannidse, Oxyrham- 

 phidte, Pipridge, Cotingidse, ] Phytotomidse, Philepittidte, Pittidse, ] Xenicidse, and 

 Euryltemidge. | By | Philip Lutley Sclater. ] London: | Printed by order of the Trus- 

 tees. 1 1888. I [Constituting Vol. xiv of the "Catalogue of the Birds in the British 

 Museum." The Tyrannidse on pages 2-280.] 



d As an example may be cited the reference of one .species of the particularly homo- 

 geneous genus Sayornis to the"Tyrannin8e," and the remaining species to the "Ta;ni- 

 opterinse," almost at opposite extremes of the arrangement! 



e The Biology of the Tyrannidaj with respect to their Systematic Arrangement. By 

 Dr. H. von Ihering. The Auk, xxi, July, 1904, 313-322. 



