Brewster on Certain Polioptilee . I 
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. plumb eq. 
All the early descriptions unmistakably relate to the more eastern 
species. Baird’s plumbea was based on an Arizona specimen ; 
the originals of Cassin’s plate and description of ‘ 4 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 typical of the 
California form, but Lawrence’s name melanura is scarcely 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 discovery 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 
difference 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 wTich it presented. Nor is this the only instance 
which has come under my notice, where the fruits of Mr. Ridgway’s 
well known critical talents have been generously placed at the 
disposal of others. 
Polioptila nigriceps. Baird. 
During my study of the North American Polioptilee , 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 P. plumbea: hence I was not greatly 
