Numbers
one of three species in this genus in North America listed at
All-LepsSize
wingspan about 33 mm, based on photo of CBIF specimen
larvae to 23 mm
Identification
Adult: forewing light brown with dark speckling, pale veins, and diffuse dark median line which is slightly wavy and reaches costa; apex pointed but outer margin not obviously falcate; AM and PM lines with conspicuous black dots at veins; slightly darker shading beyond PM line, blending into short faint apical dash
hindwing slightly paler than forewing with faint discal spot, dotted PM line, and no median line
Specimens identified by DNA analysis:
Range
California to British Columbia
Habitat
wet western coniferous forests
Season
adults fly in April and May
larvae from May to August
Food
larvae are solitary defoliators of conifers (Western Hemlock, Douglas-fir, Sitka Spruce, Engelmann Spruce, White Spruce, Western Redcedar, Amabilis Fir, Subalpine Fir, Grand Fir, Mountain Hemlock)
Life Cycle
overwinters as a pupa buried in soil; adults emerge in April and May; larvae present from May to August, pupation occurs in late summer
See Also
Thallophaga taylorata forewing has a straight median line that fades before reaching the costa, its outer margin is more falcate near the apex, and its hindwing has a dark median line - lacking in
T. hyperborea (
compare images of both species at CBIF)
Internet References
live larva image plus description, seasonaility, biology, foodplants, distribution (Canadian Forest Service)
presence in California; list (U. of California at Berkeley)