Todd — Studies in the Tyrannidce. 175 



great work on 'The Birds of North and Middle America' in 1907 led to its 

 more general recognition. This author assigned to it four species, but one 

 of these is almost certainly a synonym. In the present review we recognize 

 four species, including eleven subspecies, two of which are described as new. 



The species of this group agree in having a small, slender bill, a little 

 wider than high at the base, with weak rictal bristles, and oval nostrils, with 

 an inner shelf or flap apparent. The culmen is prominently ridged, and the 

 tip distinctly decurved. The wings are rather long for this family, with the 

 wing-tip about equalling the exposed culmen. The seventh, eighth, and 

 ninth primaries are longest, and the outer primaries in many individuals are 

 more or less narrowed terminally, or even distinctly emarginate (but never 

 "scooped" as in Mionectes), the precise character and extent of this modifi- 

 cation varying greatly. The tail is even, and approximately three-fourths 

 the length of the wing. The feet are weak, but the claw of the hind toe is 

 relatively prominent. The pattern of coloration is olive green above and 

 deep buffy or ochraceous below, the head all aroimd being gray in one 

 species. 



So far as we can discover there is only one character of value by which to 

 distinguish Pipromorpha from Mionectes, namely, the different shape of the 

 ninth primary. Mr. Ridgway says that in Pipromorpha this feather is 

 "normal, " but as a matter of fact three or four of the outer primaries are so 

 often narrowed or sharply emarginated terminally that it is very misleading 

 to describe it in this way. Probably the individuals showing these pecul- 

 iarities are older birds, but at any rate sex has certainly nothing to do with 

 the matter. Whether under the circumstances Pipromorpha should still be 

 kept separate from Mionectes is a question which we need not discuss at 

 present. 



Pipromorpha is a group characteristic of the forest region in the Tropical 

 Zone, and enjoys an extensive range in the American Tropics, from southern 

 Brazil and northern Argentina north to eastern Mexico, a distinct species 

 having been developed at either extremity of this range. It is remarkable 

 for including two other species, perfectly distinct, but yet so closely related 

 that up to the present they have passed for one form, living side by side 

 throughout an immense area in Bolivia, Brazil, and Guiana. When more 

 is known about the life-histories of these two forms we may find that they 

 occupy different habitats, but the problem of their origin and present 

 distribution is not easy to solve. Apparent gaps in the range of the group 

 as for instance that existing in northern Venezuela, open up other interesting 

 questions. Seasonal and individual variation is considerable, and intro- 

 duces complications into any attempt to discriminate the races into which 

 the several species (with one exception) seem to divide. In the key which 

 follows we endeavor to arrange the various forms into what seems to be the 

 most natural and orderly sequence. The color characters upon which the 

 key is based are necessarily not absolute, but rather comparative; they are 

 those exhibited by adult birds in fresh plumage. 



