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Species Ennomos magnaria - Maple Spanworm - Hodges#6797

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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 Ennomini
Genus Ennomos
Species magnaria (Maple Spanworm - Hodges#6797)
Hodges Number
Other Common Names
The notched wing
Notched-wing Geometer
Notch-wing Moth
Synonyms and other taxonomic changes
Ennomos magnaria Guenée, [1858]
Ennomos magnarius is an alternate spelling
Wingspan 43-60 mm; female larger than male.
Adult: resembles an autumn leaf - wings deeply, unevenly scalloped, bright orangish-yellow, variably spotted with brown, shaded with reddish-brown toward outer margin, and held 30-45 degrees above horizontal when at rest (a distinctive feature, visible at a distance).

Larva: a superb twig mimic - body green, brown, or gray, dappled with minute white spotting; pronounced leafscar-like swellings; head flattened and directed forward with long antennae; legs of third thoracic segment greatly swollen at their base, commonly held out from body; dorsum of second and fifth abdominal segments, and venter of third with raised transverse ridges; eighth abdominal segment with low, darkly pigmented dorsal warts.
[adapted from description by David Wagner and Valerie Giles]
Coast to coast in southern Canada and northern United States, south in the east to Florida and Louisiana, south in the west to California(1).
Moth Photographers Group - large range map with collection dates.
Mixed and deciduous forests and woodlots; adults are nocturnal and attracted to light.
Adults fly from July to October.
Larvae are found from May to August.
Larvae feed on leaves of alder, ash, basswood, birch, elm, hickory, maple, oak, poplar.
Life Cycle
One generation per year; eggs are laid in a row on the food plant; larvae spin a cocoon among foliage rather than pupating in or on the ground; overwinters as an egg.
The adult at rest inclines its wings at an angle, giving the appearance of a curled autumn leaf. Most moths hold their wings out flat or folded together over their abdomen.

The caterpillar is an excellent twig mimic: it has "convincing 'leaf scars' on segments 5 and 8, while its spiracles resemble the lenticels on an alder twig". [Jeremy Tatum]
Print References
Powell, J.A. & P.A. Opler 2009. Moths of Western North America. University of California Press. p. 215; plate 29, fig. 30. (2)
Internet References
live larva and adult images plus description of larva (Jeremy Tatum, Butterlfies and Moths of Vancouver Island)
live larva image plus description, food plants, seasonality (David Wagner and Valerie Giles, Caterpillars of Eastern Forests; USGS)
live adult images plus flight season (Lynn Scott, Ontario)
pinned adult image (James Adams, Dalton State College, Georgia)
pinned adult image plus description and food plants (Jeff Miller, Macromoths of Northwest Forests and Woodlands; USGS)