8 PROCEEDINGS OF THE NATIONAL MUSEUM vol. T4 



outlying genera with their respective affines in Bamleuterus are such 

 as to render highly probable this view of their relationship. The 

 case of PhaeothJypis, however, is not quite so clear; it may have 

 developed independently of BasUeuterus^ and some of its forms may 

 eventually have been modified in the direction of the latter group. 

 In all of the cases here cited we have a good illustration of the 

 persistence and constancy of color characters as an indication of 

 affinities between given forms, while so-called structural characters 

 have been modified. How much weight should be accorded the 

 former in discriminating genera one from the other is an open ques- 

 tion, but it is clear that they should be used with caution, 



SYNOPSIS OF THE GENERA 



(Basileuierm auci its Allies) 



A.^ Pileum with a vertical crest; outer primary short Myiothlypis. 



A.^ Pileum plain; outer primary longer. 



b.' Tarsus less than one-third as long as the wing; tail with white terminal 



spots Euthlypis. 



b.' Tarsus one-third as long as the wing, or longer; tail without whi e 

 terminal spots. 



c' Tail shorter than thr secondaries, bicolored Phaeothlypis. 



c' Tail longer than the secondaries, unicolored, 



d.' Tail shorter than the wing Basileuterus. 



d.- Tail longer than the wing, its rectrices naiTowed Idiotes. 



The genera Myiothlypis and Euthlypis (both monotypic) will not 

 be further considered in the present connection. The others will be 

 treated in detail. 



PHAEOTHLYPIS, new g-enus 



Generic characters. — Similar to Basileuterus^ but with the bill 

 relatively wider, always broader than deep at the nostrils; tail rela- 

 tively shorter, much less than the distance from the bend of the wing 

 to the end of the longest secondaries, the outstretched feet reaching 

 beyond its tip; and style of coloration very different, the tail being 

 always bicolor, with a pale basal and dark terminal half. 



Type. — Muscicapa fulvicauda Spix. 



Remarks. — It would seem as if this group ought to be removed 

 from Basileuterus.) if an intelligible diagnosis of the latter is to be 

 achieved. The reduction in length of the tail is a marked feature, 

 and is correlated with a color pattern tliat is unique in this family. 

 The aquatic habits of the several species, which resemble those of 

 the water thrushes iSeiurus motacUla and S. novehoracensis) liave 

 been commented on by several authors, and are certainly very dif- 

 ferent from those of the typical Basileuteri. 



The phylogeny of this genus seems fairly clear from a considera- 

 tion of the respective geographic ranges of its several members. The 



