13. COLUBRIDJE 



whole, and notwithstanding wide individual variation every- 

 where, it may be said that the coloration becomes lighter 

 toward the south and is gradually changed to that of T. sir- 

 talis infernalts. This color change seems to occur more rapidly 

 (i.e., farther north) than the change in number of gastro- 

 steges. 



Distribution. — This northern form of the Pacific Gar- 

 ter Snake inhabits the coast region of British Columbia, 

 Washington, Oregon, and California south to San Fran- 

 cisco Bay, intergrading toward the south and east in Cali- 

 fornia with T. iirtalis infernalis. In the far north it ranges 

 east to Idaho, or possibly to Montana. 



I have examined specimens: 



From British Columbia, collected at Union Bay, Bayne 

 Island, Vancouver Island (Alberni Valley), and Lillooet 

 River Valley. It has been taken at Sumass and Cheluk- 

 weyuk prairies, Bella Coola, Comax Lake, Lund, Gabriola 

 Island, Donald, Kaslo, and Union Bay. 



From Idaho, from Washington (Weiser), Ada (Boise), 

 Boise (Payette Lake), and Jerome (Blue Lakes) counties. 



From Washington, from Clallam (Neah Bay, Lake 

 Crescent), Jefferson (Port Townsend), San Juan (San Juan 

 Islands), Whatcom (Glacier), Snohomish (Index, Darring- 

 ton). King (Seattle), Chehalis (Quiniault and Melbourne), 

 Mason (Lake Cushman), Pierce (Steilacoom, Mount 

 Rainier, Longmire), Pacific (Holcomb and South Bend), 

 Lewis (Toledo), Clark (Vancouver), Skamania (Stevenson, 

 Carson), Klickitat (Trout Lake), Yakima (Indian Reserva- 

 tion, North Yakima, Mabton), Chelan (Stekekin, Chelan), 

 Stevens (Springdale), and Whitman (Pullman), counties. 



From Oregon, from Clatsop (Olney and Gearheart), 

 Tillamook (Garibaldi, Tillamook, Trask River), Yamhill 



