Moths of North Carolina
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Hyphantria Members:
394 NC Records

Hyphantria cunea (Drury, 1773) - Fall Webworm Moth


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Taxonomy
Superfamily: Noctuoidea Family: ErebidaeSubfamily: ArctiinaeTribe: ArctiiniP3 Number: 930319.00 MONA Number: 8140.00
Comments: The only member of its genus in North America. Two species, cunea and textor, have been recognized in the past (e.g., Brimley, 1938; Forbes, 1960), but only cunea is considered valid now (Hodges, et al., 1983).
Identification
Field Guide Descriptions: Covell (1984); Beadle and Leckie (2012)Online Photographs: MPG, BugGuide, GBIF, BOLDTechnical Description, Adults: Forbes (1960)Technical Description, Immature Stages: Forbes (1960); Wagner (2005)                                                                                 
Adult Markings: Adults are white with variable amounts of black spotting. They are typically smaller but similar to Spilosoma species, also possessing yellow on fore-coxae and femora like all but S. latipennis. Particularly similar to S. congrua, with both possessing all white abdomens and overlapping in size. The antennal shaft of Hyphantria is typically black, however (at least in the typical form, Forbes, 1960), whereas it is usually white in Spilosoma species (Forbes also describes form textor of Hyphantria as having white shafts). Hyphantria are also usually smaller, slimmer, and occasionally much darker than Spilosoma.
Wingspan: 25 - 39 mm (Covell, 1984)
Adult Structural Features: Hyphantria only possess a single pair of tibial spurs (terminal) on the hind-legs instead of the two pairs found in Spilosoma (Forbes, 1960).
Adult ID Requirements: Identifiable from photos showing hindwings, abdomen, or other specialized views [e.g., frons, palps, antennae, undersides].
Immatures and Development: Larvae are social, building large communal webs that are quite conspicuous; unlike the Eastern Tent Caterpillars, which build their webs at branch crotches, Hyphantria larvae build theirs out on the tips of the branches. The larvae are highly variable in coloration, ranging from pale yellowish-green to dark gray (Wagner, 2005). Some of the hairs are extremely long, greater than 4-5 body segments in length (Wagner, 2005).
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.
Distribution in North Carolina
Distribution: Occurs statewide (Brimley, 1938)
County Map: Clicking on a county returns the records for the species in that county.
Flight Dates:
 High Mountains (HM) ≥ 4,000 ft.
 Low Mountains (LM) < 4,000 ft.
 Piedmont (Pd)
 Coastal Plain (CP)

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