Hyalophora euryalus

The usual foodplant in this area seems to be Hardhack Spiraea douglasii, but I have also found the caterpillar on Arbutus menziesii. However, it has been recorded on many broadleaved trees and shrubs, and also on Douglas Fir. It has sometimes been given the English name Ceanothus Silk Moth, though so far I have not found it here on Ceanothus. The easiest way to find this moth is to spot the cocoons on Hardhack in winter. The cocoon has a double-walled structure, the inner part being brown and the outer part is almost silvery when pristine, although it may have some leaves incorporated. It is shaped like a tear-drop, pointed at the top. The cocoon is very tough, but the pointed end allows the emerging moth to emerge easily, while denying access to intruders.