Brewster on Certain Polioptilce. 105 



fornica is quite as typical as are those from Riverside and San 

 Diego. I have accordingly taken what, under the present con- 

 ditions of the case, seems to be the more likely alternative. 



The above described form, although known to ornithologists 

 for more than a quarter of a century, and during that time more 

 or less numerously represented in collections, has either passed 

 unnoticed or been unwittingly used to aggravate the confusion 

 respecting the points elucidated under the head of P. plumbea. 

 All the early descriptions unmistakably relate to the more eastern 

 species. Band's plumbea was based on an Arizona specimen; 

 the originals of Cassin's plate and description of " Culicivora 

 mexicana " were apparently from Ringgold Barracks. Texas : 

 and Lawrence's type specimen of P. melanura came from 

 the same locality. The first, and probably only distinctive 

 description of the California bird, occurs in Birds N. Am.. 

 1858, 382, where Prof. Baird, under the head of Polioptila mela- 

 nura. calls attention to some of the differences already detailed. 

 Both of his specimens, which are before me. are tvpical of the 

 California form, but Lawrence's name melanura is scarcelv eligible 

 for the new species, in view of its long application to P. plumbea. 



In this connection I wish to express my obligation to Mr. 

 Ridgway for the valuable assistance which he has given me. 

 Indeed, his share in the discoverv is by no means a small 

 one. The Arizona series was forwarded to him for comparison 

 with the Smithsonian specimens and during his examination the 

 dillerence between the former and the California birds first came 

 out. This difference, to be sure, had already been noted in my 

 study of the material embraced in my own collection, but as my 

 only California specimen was in rather poor condition, it is very 

 doubtful if I should have attached the proper importance to the 

 peculiarities which it presented. Nor is this the only instance 

 which has come under my notice, where the fruits of Mr. Ridgwa\ 's 

 well known critical talents have been generously placed at the 

 disposal of others. 



Polioptila nigriceps. Baird. 



During my study of the North American Polioptilce, I had oc- 

 casion to look up the three forms of this genus which are peculiar to 

 Mexico and Central America. All of these are white beneath and 

 otherwise closely related to /'. plumbea : hence 1 was not greatly 



