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Species Ectropis crepuscularia - Small Engrailed - Hodges#6597

Caterpillar - Ectropis crepuscularia saddleback looper - Ectropis crepuscularia Saddleback Looper - Ectropis crepuscularia Saddleback Looper - Ectropis crepuscularia Small Engrailed Cat - Hodges#6597 - Ectropis crepuscularia thick-headed cat - Ectropis crepuscularia early instar geometer (Common Gray?) - Ectropis crepuscularia Looper caterpillar - Ectropis crepuscularia
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 Boarmiini
Genus Ectropis
Species crepuscularia (Small Engrailed - Hodges#6597)
Hodges Number
Other Common Names
larva known as Saddleback Looper (
Synonyms and other taxonomic changes
Ectropis crepuscularia ([Denis & Schiffermüller], 1775)
Explanation of Names
CREPUSCULARIA: from the Latin "crepusculum" - twilight
crepuscular animals are most active during twilight (dusk and dawn), whereas nocturnal animals are most active during the night, and diurnal ones during the day
Ectropis crepuscularia is the only member of the genus in America north of Mexico.
Wingspan 30-41 mm.
small black dentate (tooth-like) markings along 3 or 4 lines that cross the wing
amount of dark banding varies from heavy to almost none, but the darkest mark on the forewing is a blackish blotch along the postmedian (PM) line near the center of the wing - distinguishing this species from Protoboarmia porcelaria (Porcelain Gray), whose darkest mark is at the costa where the PM line begins
E. crepuscularia lacks a short dark streak just below the point where the antemedian (AM) line touches the costa, and usually lacks a dark spot near the middle of the hindwing (both of these marks are present in Protoboarmia porcelaria)
Some of the various forms:

Coast to coast in North America, north to the panhandle of Alaska but not Yukon or NWT
also occurs throughout Eurasia
The main flight period appears to be March to October.
The larvae present in July and August in northern US and southern Canada.
The larvae are generalist feeders on balsam fir, hemlock, larch, cedar, spruce, apple, alder, birch, elm, maple, oak, poplar, and willow.
Life Cycle
One generation in the north; 2 or 3 in the south.
Larva, larva, pupa, Mating Pair:
(both genders with simple antennae)
See Also
Porcelain Gray - Protoboarmia porcelaria which is smaller and has a short dark streak just below the point where the antemedian (AM) line touches the costa.
Print References
Powell, J.A. & P.A. Opler, 2009. Moths of Western North America. University of California Press, p. 210; plate 28, fig. 17. (1)