PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 387 



2. Polioptila bilineata (Bonap.). 



[Note by R. R. — The black-capped PoUoptilcc of Central and South 

 America are involved at present in so much confusion that the following 

 remarks, based upon specimens in the collection of the United States 

 National Museum, may not be out of place. The latest information 

 which we have upon the subject is that contained in Salvin and God- 

 man's Biologia Centrali Americana (Aves, vol. i, pp. 50-55), and this 

 should be carefully consulted in the present connection. The authors 

 of the work quoted recognize in Central America three species of the 

 genus, besides P. cwrnlea, as follows: 



(1.) P. NiGRiOEPS Baird. Rab. — Southwestern Mexico (Mazatlau, 

 Tepic, and States of Oaxaca and Tehuantepec) ; also, Colombia and 

 Yenezuela, but not recorded from any ijart of Central America proper, 

 except San Salvador (La Union). 



(2.) P. BILINEATA (Bouap.). Hah. — Guatemala to Colombia and 

 western Ecuador. 



(3.) P. ALBiLORis Scl. & Salv. Rab. — Southwestern Mexico (Sta. 

 Efigenia and Tehuantepec City), Guatemala, and Nicaragua. 



In their treatmeut of these three species, Messrs. Sai^vin and God- 

 man make some very interesting generalizations, based ui)on certain 

 anomalies in their geographical distribution, but which appear to be 

 somewhat negatived by the evidence afforded by additional specimens. 

 Disclaiming, however, any intention of criticising the hypotheses oifered 

 by the authors of the great work in question, the following remarks are 

 presented as perhaps throwing some additional light upon this more or 

 less complicated subject. 



Of the true P. nigriccps we possess specimens only from southwestern 

 Mexico (Mazatlau and Tepic to Tehuantepec and Oaxaca). The seven 

 examples before me may each be very readily distinguished from all 

 black-lored specimens of the genus from more southern localities in the 

 collection hy the indistinct gray edgings to the tertials, all of the more 

 southern black-capped forms, with the single exception of P. bilineata. 

 having the tertials broadly and very distinctly edged with pure white. 

 P. bilineata, however, may, in every plumage, be easily distinguished 

 by the white lores and superciliaries. 



The only other black-lored form of which the Museum possesses adult 

 males is P. leucogastra. Of this, there are two adult males and two 

 young males from Bahia, and a female from Venezuela. The young 

 male has the crown plumbeous (darker than the back), the feathers 

 darker in the center, and with a distinct postocular patch of glossy 

 black. Tlie Museum also possesses an adult male from Bogota, one 

 from the Pacific coast of Central America (No. 30555, Capt. J. M. Dow), 

 and another from Grenada, Nicaragua (No. 32556), which I cannot dis- 

 tinguish in any way from the Brazilian birds, or true P. leucogastra, 

 The broad and conspicuous white edgings to the tertials at once sepa- 

 rate them from P. nigriceps. 



