"J I 8 Von Ihering, Biology of the Tyratiftidce. Liiuv 



the fact that in the species of Cnipo/egus, Lichenops, and others in 

 which the males are wholly black, the females and young are of a 

 brownish color or have a spotted plumage. Among the more or 

 less similar members usually placed in this subfamily two mono- 

 typic genera are completely different in their coloration, namely, 

 Sisopygis and Machetor?iis, which in my opinion do not belong to 

 this subfamily, but to the Elaineinae. Machetomis seems to me to 

 be allied to Pitafigns, and Sisopygis to Mionectes, Capsiempis, and 

 similar genera. While Afachetor?iis, at least in its mode of life, 

 resembles the Taeniopterinse, Sisopygis inhabits the woods like the 

 Elaineinae. 



That the Platyrhynchinte really consist of two different subfam- 

 ilies, Euscarthminae and Serphophagina;, we have shown above. 

 With the biological differences correspond such important morpho- 

 logical ones, principally those of the form of the bill, that the 

 separation here proposed will probably be accepted as being 

 naturally founded. 



In order to obtain a natural classification of the Tyrannidai it 

 is necessary to get an idea of the phylogenetic development of 

 the family. In this respect the Tyranninje, judging from their 

 large dimensions and their large, somewhat depressed bills, do not 

 represent the original form, but, as I think, an extreme branch of 

 the family. Other specialized branches are found in the Euscarth- 

 min£e and Taeniopterinai. The latter offer not only a coloring 

 somewhat uncommon in this family, but also cases of decided 

 sexual dimorphism, which evidently represents a specialization 

 acquired within the subfamily. 



Excluding from the Elaineinae the Pitanginai — large birds with 

 strong bills that biologically much approximate to true Tyranninae 

 — the Elaineinae evidently represent the group most nearly allied 

 to the ancestors of the Tyrannida. These forms are also those 

 which have the nearest relations with the Pipridae. Strongly 

 developed syndactylism, which is one of the characters distinguish- 

 ing the latter, is also very remarkable in many genera of the 

 Elaineinae, as for example in the genus Tyranniscus. 



Among the Pipridai the same fact is observable as in the Tyran- 

 nidae, namely, that sexual dimorphism in coloration exists only in 

 the more highly organized forms. In the subfamily of Piprinae 



