76 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



charientiinis, spilurus and drymoecus. These birds in colora- 

 tion are practically like southern California charienturus, being 

 no more rufescent than are most specimens from that region, 

 and less reddish than birds from the coast of Santa Barbara 

 County. In measurements the San Benito County birds are 

 shorter tailed than is typical charienturus, and thus approach 

 spilurus or else San Joaquin Valley drymoecus. There is very 

 little difference in measurements between these latter two. 



There is at hand one skin from San Luis Obispo County 

 and eight from the coast of Santa Barbara County. Some, but 

 not all, of these birds are slightly darker and more rufescent 

 above than charienturus from points farther south, but I be- 

 lieve that all are to be referred to that form. It is probably the 

 type of specimen such as I have at hand from San Benito and 

 Santa Barbara counties that formed the basis for the exten- 

 sion of the range of drymoecus to these points, but I prefer 

 to regard such birds as illustrating intergradation between 

 charienturus and spilurus, over the intermediate territory which 

 they occupy. They are with difficulty distinguished from typi- 

 cal charienturus, and are certainly quite different in appearance 

 from typical drymoecus of the Sacramento Valley. 



The excellent series of skins at hand from the coastal re- 

 gion of Los Angeles, San Bernardino and Riverside counties, 

 includes specimens in all stages and from all seasons, and, 

 judging from these, it would seem that the race charienturus, 

 as confined to southern California, is as well defined as any of 

 the forms of the genus Thryomanes. Here, too, however, 

 there is a certain amount of variation, usually in shade of ru- 

 fescence dorsally, even in specimens in fresh fall plumage taken 

 at practically the same points; differences that can hardly be 

 explained on any grounds save that they represent the varia- 

 bility existing among individuals of the one race. Segregation 

 according to age or sex yields no uniform or satisfactory di- 

 visions. 



In the series at hand there are six winter birds from points 

 at the western edge of the Mohave Desert, five from Victor- 

 ville and one from Barstow. These specimens have been re- 

 corded as drymoecus (Mailliard and Grinnell, 1905, p. 101 ; 

 Grinnell, 1901, p. 70), but I am unable to distinguish them 



