Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada

Species Nematocampa resistaria - Horned Spanworm Moth - Hodges#7010

fancy caterpillar - Nematocampa resistaria fancy caterpillar - Nematocampa resistaria fancy caterpillar - Nematocampa resistaria Filament Bearer - Nematocampa resistaria Filament Bearer - Nematocampa resistaria Horned Spanworm - Nematocampa resistaria what type of caterpillar - Nematocampa resistaria Filament Bearer (Horned Spanworm Moth larva) - Nematocampa resistaria
Show images of: caterpillars · adults · both
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Class Insecta (Insects)
Order Lepidoptera (Butterflies and Moths)
No Taxon (Moths)
Superfamily Geometroidea
Family Geometridae (Geometrid Moths)
Subfamily Ennominae
Tribe Ourapterygini
Genus Nematocampa
Species resistaria (Horned Spanworm Moth - Hodges#7010)
Hodges Number
7010
Other Common Names
Filament Bearer (caterpillar)
Synonyms and other taxonomic changes
Nematocampa limbata (formerly lumped with this Eurasian species)
Ferguson (1993) revised the NA species of Nematocampa and was the author who revised the status of the species commonly called N. limbata to N. resistaria.
Size
Wingspan 19-25 mm
Identification
MOTH
Yellowish with distinctive pattern--see photo. Note especially the single am line and the double pm line--the latter far apart at costa, almost touching below it, then separating again. Dark coloration beyond pm line variably purple to brown (1).
Dimorphism
A dimorphic species, both between sexes (sexual dimorphism) and within the males; dimorphism in females rare.
Ferguson (1993) describes this species as follows “This widespread nearctic species is distinguished by the whitish ground color of nearly all females (with rare exceptions) to the more yellowish males.” BugGuide image #40816 is a female:


Males vary from having dark blotches--images in Covell (1) and BugGuide images below, showing some of the variability,

to having none - described by Ferguson as “brown markings well developed to obsolescent”. Such markings are geographically variable that has led to them being named as separate subspecies and species.

CATERPILLAR
Strange! Eversible tentacles extend from the dorsal surface of A2 and A3. In the first photo (below, left) they are in the 'relaxed' condition; when the caterpillar is alarmed these tentacles can be extended to 2x their resting length (below, right). These same structures probably occur in other species in the genus; but otherwise I believe they may be unique.
Range
Includes eastern North America. Listed as local and uncommon (1). Reasonably common in NB, seen every year in Fredericton. Also found in Eurasia, depending on taxonomic treatment (see Remarks).
Nova Scotia to Vancouver Island, south to Florida and west to Texas.
Habitat
Deciduous forests and coniferous forests.
Season
May-August, April in deep south
Food
Larvae feed on many hardwoods and several softwood species.
Life Cycle
One generation in north, double brooded in middle states; more than double brooded in south.
Remarks
North American population now split as Nematocampa resistaria in recent treatments, and this is followed here. (See references.)
Print References
Covell, p. 373, plate 54 #12--listed as N. limbata (1)
Miller, p. 54, #75--N. resistaria (2)
Wagner, p. 194--photo of caterpillar and adult specimen (3)
Ferguson,D.C. 1993. A revision of the species of Nematocampa (Geometridae; Ennominae) occurring in the United States and Canada. J. Lep. Soc 47(1):60-77. Includes 13 B&W photos of resistaria
Internet References
Lynn Scott--N. resistaria
Randy Newman--MPG, lists as N. resistaria
Works Cited
1.Peterson Field Guides: Eastern Moths
By Charles V. Covell
2.Macromoths of Northwest Forests and Woodlands
By Jeffrey Miller, Paul Hammond
3.Caterpillars of Eastern North America
By David L. Wagner