Brewster on Certain Polioptilce . 
IOI 
ON THE AFFINITIES OF CERTAIN POLIOPTILCE, 
WITH A DESCRIPTION OF A NEW SPECIES. 
BY WILLIAM BREWSTER. 
In a collection of Arizona birds, elsewhere considered in the 
present number of the Bulletin, is a small series of Gnatcatchers, 
which brings to light some very interesting developments affecting 
the relationship of certain members of the genus Polioptila . As 
the matter seems of sufficient importance to merit special treat- 
ment, I present it separately in the following paper : 
Polioptila plumbea, Baird , et melanura Lawr . 
It has been somewhere suggested that P. plumbea might after 
all be only a geographical race of P. ccerulea , but the specific 
distinctness of the former from P. melanura seems never to have 
been questioned.* The fact that their distribution was the same 
has effectually precluded any suspicions of varietal affinity, and 
the real secret, singularly enough, has eluded the few ornitholo- 
gists who have paid any attention to the subject. 
But thanks to the exertions of Mr. Stephens, who it seems has 
for some time suspected their identity, I now have before me a 
perfect connecting series between the two supposed species. 
A brief consideration of five of the specimens, all of which 
were taken near Tucson during the spring of 1880, will present 
the case as fully as is desirable. 
The first (No. 4980, author’s collection) d, March 3, is typical of the 
state known as P. plumbea , the black on the head being restricted to a 
short stripe on each side of the crown, which, beginning nearly above 
the anterior margin of the eye, extends backward to a short distance 
behind it, and is bounded below by a superciliary line of ashy-white. 
In the second (No. 4982) Maixh 4, the black stripe broadens, en- 
croaching on the superciliary line, and meeting its fellow across the 
top of the head between the eyes, in a narrow but decided band of black, 
but leaving the anterior portion of the forehead ashy. 
The third (No. 4983) March 5, has the whole crown essentially black, 
but traces of the superciliary line remain, and in addition to an ill-defined 
frontal-band of ashy, there are occasional feathers of that color scattered 
among the darker ones. 
* COoper hinted such a suspicion (Birds of Cal., I, p. 38) but his suggestion has 
been generally ignored. 
