The Ceanothus Silkmoth (Hyalophora euryalus) is a moth of the Saturniidae family. It is found in the dry intermontane valleys and interior of British Columbia (as far north as Prince George along the Fraser River) south to Baja California. The wingspan is 89–127 mm. Adults are on wing from January to July depending on the location. There is one generation per year. The larvae feed on Ceanothus, Rhamnus californica, Prunus emarginata, Arctostaphylos, Alnus, Betula, Corylus, Ribes, Pseudotsuga menziesii, Arbutus menziesii and Salix.