Synopsis of the Genus Thryomanes 



27 



and later study have shown the geographic significance of 

 these differences. Although Thrijoiiianes beicickii ariho- 

 rius has a comparatively limited distribution, it is a well- 

 marked form and certainly deserves subspecific separation. 

 Birds from southwestern British Columbia show the most 

 extreme manifestation of characters, but birds from Mt. 

 Vernon, northwestern Washington, are undoubtedly refer- 

 able to the same subspecies although they verge somewhat 

 toward. Thryomanes hewickii calophonus. The difference 

 between Thryomanes heivickii ariborius and Thryomanes 

 heivickii calophonus is fairly comparable to that existing 

 between Thryomanes beicickii marinensis and Thryomanes 

 beivickii cpilurus, the characters in each case being wholly 

 those of coloration ; and the former two races are but large 

 editions of the latter two. As already noted under Thiy- 

 omanes beicickii calophonus, birds from Vancouver Island 

 are to be referred to true Thryomanes beivickii calophonus, 

 rather than to the present race. 



There is apparently no difference in size between Thry- 

 omanes beicickii ariborius and Thryomanes bewickii calo- 

 phonus, as the following detailed measurements of the 

 former will show: 



