Ceanothus Silkmoth Caterpillar (Hyalophora euryalus): Caterpillars can be difficult to identify, but we’re pretty sure this is the larva of a Ceanothus Silkmoth. They can be found from British Columbia east to western Montana, south through Washington, western Oregon, and California to Baja California Sur. There is only one brood a year with adults generally emerging from mid May to mid June in western Montana. This individual has a few more weeks of growing to do before forming a cocoon for its winter “nap” and transformation next spring. Photo by Stacey Terrill on 7/18/18 in Dillon, MT.