Thuja plicata
The larvae feed on "Juniperus communis", "Juniperus scopulorum" and "Thuja plicata". Full-grown larvae reach a length of 20 mm. There are two colour morphs. The common form is green with a greenish-yellow head. The second form is brown. Larvae can be found from mid-May to early August and pupation takes place from July to August. The species overwinters as an egg.