Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Clickable Guide
Moths Butterflies Flies Caterpillars Flies Dragonflies Flies Mantids Cockroaches Bees and Wasps Walkingsticks Earwigs Ants Termites Hoppers and Kin Hoppers and Kin Beetles True Bugs Fleas Grasshoppers and Kin Ticks Spiders Scorpions Centipedes Millipedes

Upcoming Events

Discussion, insects and people from the 2018 BugGuide Gathering in Virginia, July 27-29

Photos of insects and people from the 2015 gathering in Wisconsin, July 10-12

Photos of insects and people from the 2014 gathering in Virginia, June 4-7.

Photos of insects and people from the 2013 gathering in Arizona, July 25-28

Photos of insects and people from the 2012 gathering in Alabama

Photos of insects and people from the 2011 gathering in Iowa

Photos from the 2010 Workshop in Grinnell, Iowa

Photos from the 2009 gathering in Washington


Species Lycia ursaria - Stout Spanworm Moth - Hodges#6651

hairy geometer - Lycia ursaria - male Stout Spanworm/ Bear moth, 5:21pm - Lycia ursaria 6651 Stout Spanworm Moth - Lycia ursaria - male Mystery Moth-7 - Lycia ursaria - male confirm - Lycia ursaria? - Lycia ursaria Unidentified Moth 1 - Lycia ursaria - male Unknown Caterpillar - Lycia ursaria A Geometrid Moth - Lycia ursaria - 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 Lycia
Species ursaria (Stout Spanworm Moth - Hodges#6651)
Hodges Number
Synonyms and other taxonomic changes
Lycia ursaria (Walker, 1860)
Biston ursaria Walker, 1860
locally common
wingspan to 45 mm
Adult: thorax and abdomen bulky, very hairy; male forewing broad, evenly gray, heavily speckled with black; three black wavy lines (sometimes broken) cross the wing; subterminal line white; hindwing similar but color more muted; female has reduced wings and does not fly
southern Canada and northern United States, south to New Jersey and Iowa
mixed and deciduous woods; males are nocturnal and come to light
adult males fly from March to June
larvae feed on the leaves of alder, apple, ash, basswood, birch, blueberry, dogwood, elm, hawthorn, poplar, willow and other broadleaved trees and shrubs
Life Cycle
one generation per year
a bulky and very hairy moth, easily mistaken for a noctuid, notodontid, or other non-geometrid moth
See Also
Twilight Moth (Lycia rachelae) male lacks speckling on wings, and has yellowish strip along costa of forewing (compare images of both species at CBIF)
Woolly Gray (Lycia ypsilon) male has grayish-brown forewing with lighter median area, and a more southern distribution (doesn't occur in Canada)
Print References
Rindge, Frederick H. 1975. A revision of the New World Bistonini, (Lepidoptera, Geometridae). Bulletin of the AMNH ; v. 156, article 2.(1)
Internet References
pinned adult image of male (CBIF)
live adult image of male (Lynn Scott, Ontario)
distribution in Canada list of provinces (CBIF)
Works Cited
1.A revision of the New World Bistonini, (Lepidoptera, Geometridae).
Frederick H. Rindge. 1975. American Museum of Natural History 156(2):.