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Species Phigalia plumogeraria - Walnut Spanworm Moth - Hodges#6661

Stick like caterpillar - Phigalia plumogeraria blacky - Phigalia plumogeraria Walnut Spanworm Moth - Phigalia plumogeraria - female Geometer? - Phigalia plumogeraria - male Geometer? - Phigalia plumogeraria - male Geometer? - Phigalia plumogeraria - male Geometridae: Phigalia plumogeraria - Phigalia plumogeraria Unknown Moth - Phigalia plumogeraria - male
Show images of: caterpillars · adults · both
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
Other Common Names
Walnut Spanworm (larva)
wingspan 32-45 mm, based on two Internet photos
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
British Columbia to California, east to Utah and Wyoming
adults fly from January to April
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)
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)