106 Brewster on Certain Polioptilce. 



surprised to Mud that this supposed distinctness, inter se, apparent- 

 ly rests upon pretty much the same general grounds as has that of 

 P. plumbed and P. melanura. The latest information regarding 

 them appeared in Godnian and Salvin's " Biologia Centrali- 

 Americana," Part II, November, [879, where their differential 

 characters are set forth as follows : 



Polioptila nigriceps. ■• P. ccerulece similis, sed pileo toto cum 

 loris et superciliis nitenti-nigris." 



Polioptila bilineata. "P. nigricipiti affinis, sed loris et 

 superciliis albis, striga postoculari tantum nigra, capiti nigro 

 conjuncta:" 



Polioptila albilpris. "P. nigricipiti affinis, sed loris (nee 

 superciliis) albis distinguenda." 



If, by the above, we are to understand that /'. nigriceps differs 

 from /'. ccerulea only in having " the whole pileum, with the 

 lores and upper eyelids, shining black" it is of course separable 

 from P. filumb ea by the different coloring of the tail feathers, 

 which would he like those of /'. ccerulea. But in view of the age- 

 variations which occur in /'. plnnibea. we are certainly warranted 

 in entertaining a suspicion that bilineata and albiloris are only 

 the immature stages of /'. nigriceps. 



'flie condition known as P. bilineata is almost exactly repro- 

 duced, relatively. l>v my specimen No. 4981, which has the lores 

 and upper eyelids ashy-white; while that called albiloris is ven 

 nearly duplicated by X >. 49S3 in which the lores remain ashy- 

 white while the black of the crown encroaches on the white of 

 the eyelids. 



The English ornithologists are evidently in some perplexity re- 

 garding these allied forms, lor in some general remarks which follow 

 the specific matter they observe : " Having thus given some account 

 of the three forms of black-headed Polioptilce found in Central 

 America ( P. nigriceps with the lores wholly black. /'. albiloris 

 with the lores white, and /'. bilineata with both lores and supercili- 

 aries white) it remains to consider the position of certain specimens 

 which seem to have intermediate characters connecting two or all 

 of these forms together. These birds were obtained, with a female 

 of the true P. bilineata. near La Union in San Salvador, and have 

 the lores black, with a few white feathers intermingled. . . . Putting 

 P. albiloris aside, and observing the distribution of P. nigriceps 

 and P. bilineata. we find the curious fact that the ranges of these 



