Nelson New JBirds from /Southern Mexico. 



157 



Specific characters. Pattern of coloration as in G. melanops, but black 

 mask extends higher upon forehead; light area bordering black mask 

 yellow; upperparts darker olive-green; underparts richer yellow; culmen, 

 tail, and tarsus longer. 



Description. A broad black mask covering front and sides of head in 

 cluding orbits; black mask bordered posteriorly by a yellow band extend 

 ing about to middle of crown and down on sides of neck; rest of crown 

 and nape bistre brown overlying and concealing yellow bases of feathers; 

 rest of upperparts dark olive green; underparts bright gamboge yellow 

 most intense on neck and breast; flanks washed with olive brown. 



measurements of three species of Geothlypis. 



Remarks. In fresh plumage the brown on crown and nape hides the 

 basal yellow of the feathers, but as the plumage becomes worn the brown 

 gradually disappears and the yellow band on crown broadens until in one 

 of our series of eleven specimens the crown and nape are entirely yellow 

 much as in G. flaviceps. The differences in size and proportions serve at 

 once to distinguish the two species and the same holds good in regard to 

 another closely related species, G. flavovelatus. 



The female of G. chapalensis has a dull brown forehead and dull olive 

 green crown, contrasting strongly with the yellow forehead and lighter 

 green crown of this sex in G. flaviceps. 



This species is based on eleven specimens. 





Thryophilus sinaloa russeus, subsp. nov. 

 Russet Wren. 



Type.^o. 185,893, ad. $, U. S. Nat. Mus., Biological Survey Coll. 

 From Acahuizotla, Guerrero, Mexico. Collected May 9, 1903, by E. W. 

 Nelson and E. A. Goldman. 



Distribution. Known only from type locality, but probably occurs in 

 brushy foothills of the Sierra Madre del Sur throughout most of its ex 

 tension in Guerrero. 



Subspecific characters. Witters from T. sinaloa mainly in the much 

 brighter, more russet brown of upperparts of head, body, and wings; 

 upper tail coverts and tail brighter, more cinnamon rufous; dark bars on 



