AdultThis is the largest species of Erynnis in BC, with a forewing length of 1.8-2.1 cm, and it generally flies in close association with Garry oak. It is best, however, to examine the male genitalia to ensure proper identification. The ventral process of the left valve is extremely long; the middle lobe is elongated and strongly curved towards the ventral process. The sexes are dimorphic, with the female wings being lighter. In particular the spots of the post-median row of both wings are larger in the female. The male possesses the costal fold characteristic of the genus.
Immature StagesHardy (1958b) described the immature stages of the Vancouver Island populations in detail from larvae collected on the foodplant. The mature larval head is flesh-coloured with orange spots on each side and covered with fine hair. The body is sage green with pale yellow subdorsal lines and pale yellow intersegmental rings. The spiracles are white.
SubspeciesNone. The type locality of the species is California.