126 Nehon — Names of Certain North American Birds. 



The birds of this genus in western Mexico have hitherto been 

 considered specifically distinct from those of eastern Mexico but 

 the series in the Biological Survey Collection show that al)out 

 the Isthmus of Tehuantepec and southward intergradation takes 

 place so that a rearrangement of the Mexican forms becomes 

 necessary. The Soutli American species becomes Tdiniacins 

 ariHcvd (Cabanis) and tlic Mexican species should stand as fol- 

 lows : 



Tan()<irjiix ;fiicii.^ n'linis (Wagler) Western Mexico. 



li II itxsiiiiilis (Xt'lson) Southwestern Mexico. 



(( a iiiroliifi-dtiis (Ivcsson) Eastern Mexico. 



