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



cile with the generally variable nature of the several subspecies 

 as observed at this time. 



The above statements must not be understood as weighing 

 against the validity of the several "subspecies" so far de- 

 scribed from California, for in nearly every case where a 

 name has been applied to a local race it covers an aggregation 

 of characters fairly easily defined and recognized. In fact, 

 the races of Thryomanes bewicki, as occurring on the 

 mainland of the Pacific coast, may be taken as an 

 ideal illustration of subspecific division as it is ap- 

 plied in systematic ornithology. There are six recog- 

 nized forms in this region — marinensis, spilurus, drymoecus, 

 charienturus and eremophilus in California, and calophonus in 

 the coast region to the northward. In every case it is an easy 

 matter to distinguish typical examples of the races. Typical 

 specimens are not necessarily topotypes. The best manifesta- 

 tion of a race may be found at some distance from the type 

 locality; usually at about the center of the geographical area 

 occupied. As departure is made from the habitat of one race 

 toward that of another, in just such proportion is variation 

 encountered among individuals of the races. Geographical 

 continuity of range with corresponding intergradation of char- 

 acters is usually taken as the test of subspecific, rather than 

 specific, difference, but there are few instances among North 

 American birds where these, conditions are as ideally met with 

 as among the Pacific coast forflis of Thryomanes bewicki. 



A brief resume of the course of variation in some of the 

 most salient features of these races may be profitable. At the 

 extreme northern limit of the species, on the mainland of 

 southern British Columbia and Washington, is calophonus, of 

 relatively large size and extremely dark coloration. On the 

 adjacent Vancouver Island is a .slightly paler colored, rather 

 more reddish, form (included under the name calophonus), 

 of practically the same size. Farther south, on the coast of 

 northern California, southward to the Golden Gate, is marin- 

 ensis, about like Vancouver Island calophonus in color but ap- 

 preciably smaller. South of the Golden Gate is spilurus, oc- 

 cupying the narrow coastal strip west of the Coast Ranges, 

 south to about the southern end of Monterey Bay. This form 

 is of a somewhat paler and brighter red than is marinensis, 



