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Species Phigalia plumogeraria - Walnut Spanworm Moth - Hodges#6661

Phigalia plumogeraria Stick like caterpillar - Phigalia plumogeraria unknown moth - Phigalia plumogeraria Gray moth - Phigalia plumogeraria Unknown Moth - Phigalia plumogeraria Unknown Moth - Phigalia plumogeraria Walnut Spanworm Moth – (Phigalia plumogeraria) - Phigalia plumogeraria - male Phigalia plumogeraria female - Phigalia plumogeraria - female
Show images of: caterpillars · adults · both
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Lepidoptera (Butterflies and Moths)
Superfamily Geometroidea (Geometrid and Swallowtail Moths)
Family Geometridae (Geometrid Moths)
Subfamily Ennominae
Tribe Bistonini
Genus Phigalia
Species plumogeraria (Walnut Spanworm Moth - Hodges#6661)
Hodges Number
6661
Other Common Names
Walnut Spanworm (larva)
Size
wingspan 32-45 mm, based on two Internet photos
Identification
Adult: female wingless, cannot fly; male antennae bipectinate; forewing gray with fine speckling and three inconspicuous dark gray lines; hindwing light brownish-gray with faint discal spot and two indistinct lines

Larva: gray twig mimic with small dorsal spine on abdominal segments 1-3 and 8
Range
British Columbia to California, east to Utah and Wyoming
Season
adults fly from January to April
Food
larvae feed on leaves of Antelope Bitterbrush (Purshia tridentata), walnut, and willow
See Also
other Phigalia species are more prominently marked, and none occur west of Saskatchewan. The males can be separated from all other members of the genus by the antennae having fewer segments and much longer pectinations, by their larger wings, and by the forewings above being a unicolorous gray with almost straight cross lines
Internet References
live larva and adult images of male and female, plus foodplants (Jeremy Tatum, Butterflies and Moths of Southern Vancouver Island)
pinned adult image plus photos of related species by Jim Vargo (Moth Photographers Group)
common name reference and foodplant (Washington State U.)
presence in California; list (U. of California at Berkeley)
presence in Wyoming; list search species 'plumogeraria' (Lepidopterists Society season summary (U. of Florida)
presence in Utah; list (Joel Johnson, Utah Lepidopterists Society)
distribution in Canada British Columbia only (CBIF)