1 04 Brewster on Certain Polioptilce, 



Dimensions. Length, 4-50; extent. 6.10: wing, 1.84; tail, r.8o; tarsus, 

 .73; bill, (culmen), .50; from nostril. .30. 



(No. 719-. National Museum) Fort Yuma. Similar to the J but with 

 the crown deep plumbeous ; the abdomen anil crissum pale chestnut; the 

 external webs of second pair of rectrices margined with white. 



Young $* (Xo. 2149. Coll. of R. Ridgway) Saticoy, Cala.. Nov. 24. 

 1872. Coll. J. G. Cooper. Similar to the °. but with the plumbeous of 

 the crown clearer; the brownish' wash beneath confined to the abdomen 

 anil crissum. the white of tail restricted to outer pair of rectrices and a 

 narrow tipping on the second pair. 



Four specimens examined. 



Upon comparing the California bird with /'. plumbea as rep- 

 resented by my Arizona specimens, the following differences ap- 

 pear. The ash of the upper parts is decidedly plumbeous in- 

 stead of bluish : the throat, breast and sides dull ashy instead of 

 ashy-white : the abdomen, crissum and under tail-coverts fulvous, 

 in some specimens pale chestnut : the light edging of the tail 

 feathers confined to the outer pair of rectrices (with sometimes a 

 slight tipping on the second pair) and on these restricted to the 

 extreme tips and a narrow margin along the outer web ; the lining 

 of the wings pearl-ash instead of white and the secondaries and 

 tertials edged with light brown. There is no pure white any- 

 where on the bird, and the general aspect beneath is nearly as dark 

 as in the Cat-bird. 



The proportions also apparently differ. The bill and tarsi are 

 longer and more slender than those of /'. -plumbed but the wings 

 and tail, especially the latter, are generally shorter than in the 

 specimens of plumbea which my collection embraces. 



These differences, which characterize all stages alike, are so 

 decided and constant that I believe them to be of specific value. 

 In view of the general law that Pacific coast birds tend to darker 

 coloring than their aftines from the interior it is of course not im- 

 possible that a gradual transition will eventually be found to exist 

 between these closely allied Gnatcatchers. Cooper, howeyer. 

 found both species in winter at Fort Mohave, where each preseryed 

 its distinctive characters. t and my Fort Yuma specimen of cali- 



* It would be indeed remarkable if this species has no immature stage corresponding 

 to that of P. plumbea. But putting aside some doubtful California citations, there is 

 nothing to show that any such specimens have ever been taken. Mr. Stephens writes 

 me that he has examined numerous California examples, but among them has found 

 no spring males without the full black cap. 



t Birds of Cal., I, 1870, 37. 



