Vo1 iqo7 :IV 1 Bangs, Birds from Western Costa Rica. 297 



Gymnocichla nudiceps erratilis subsp. now 



Ninety-two specimens, both sexes, young and adults, Boruca, Paso 

 Real, Pozo del Rio Grande and Barranca, April-August. 



Cotypes, from Boruca, Costa Rica, adult 9, No. 18990, and adult <?, 

 No. 18991, coll. of E. A. and O. Bangs. Collected June 11, 1906, and 

 May 22, 1906, respectively by C. F. Underwood. 



Characters. Similar to true G. nudiceps of northern Colombia and 

 Panama, but larger, wing and tail longer (in the adult c? of the new form 

 averaging, wing, 78.5; tail, 62; in true G. nudiceps averaging wing, 76; 

 tail, 58), bill and tarsus of about the same length in both forms. The 

 adult male not different in color, from the adult cf of true G. nudiceps; 

 the adult female, however, much more intensely ferruginous, the upper 

 parts deeper and redder and without the olivaceous tinge seen in true G. 

 nudiceps; the whole underparts deep, strong ferruginous, scarcely if 

 any paler on belly, quite different in color from the orange-rufous under- 

 parts of true G. nudiceps which are also duller and paler in middle of belly; 

 tail and wing, especially the edgings of lesser and middle coverts, much 

 deeper ferruginous. 



Remarks. Cherrie in the paper referred to in the introduction of this 

 article recorded for the first time, I believe, the occurrence of Gymnocichla 

 nudiceps in western Costa Rica. Underwood found the bird to be common 



