Vol. VI] SWARTH— RACES OF BEWICK WREN 73 



treme southern outpost of Sierran drymoecus, where that race 

 abuts on eremophilus. The grayish cast of the dorsal surface 

 may well be explained as evidence of intergradation between 

 the two. 



From Walnut Creek and Mount Diablo, Contra Costa 

 County, there is a series of two adults and 12 juvenals. The 

 adults, June birds in excessively worn plumage, bear no re- 

 semblance to the ruddy colored spilurus of the nearby coast 

 region. The young birds, too, lack the clear reddish tone of 

 Palo Alto juvenals, and are very similar to young birds from 

 the Sacramento Valley. The series is unsatisfactory in the 

 lack of fresh plumaged adults, but is apparently to be referred 

 to drymoecus, though tending toward the coast form spilurus. 

 Birds from the east shore of San Francisco Bay (Berkeley, 

 Oakland, etc.), the nearest point in the range of spilurus, 

 are themselves for the most part not typical of that race, so 

 that specimens from this whole general region may be regarded 

 as illustrating intergradation between the coastal spilurus and 

 drymoecus of the interior. The reference of the Walnut Creek 

 and Mount Diablo birds to drymoecus is necessarily based al- 

 most wholly upon the appearance of the juvenals. Fortunately 

 there are certain characteristics at this stage, as shown by the 

 large series from the Sacramento Valley, apparently justify- 

 ing such procedure. 



There is one specimen at hand from a point outside of the 

 general breeding range of drymoecus, which I feel obliged to 

 refer to this form. This is an immature female (no. 5268, 

 Grinnell coll.) taken at Palo Alto, California, September 27, 

 1902, and in complete first winter plumage. In color and pro- 

 portions this bird appears to be unequivocally drymoecus. 

 Without conceding any regular migratory habits to the form, 

 it is quite possible for occasional individuals to stray during 

 late summer and fall for as short a distance as is indicated 

 by this capture. I believe this specimen to be such a wanderer 

 from the breeding ground. 



The subspecies Thryomanes bewicki drymoecus has been 

 denied recognition by the American Ornithologists' Union 

 Committee, and declared to be "not separable from Thryo- 

 manes b. spilurus" ( 1901, p. 314) . At a later date, in the third 

 edition of the Check-List (1910, p. 339), the ascribed range 



