Moths of North Carolina
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61 NC Records

Herpetogramma aeglealis (Walker, 1859) - Serpentine Webworm Moth

Taxonomy
Superfamily: Pyraloidea Family: CrambidaeSubfamily: PyraustinaeTribe: SpilomeliniP3 Number: 801191.00 MONA Number: 5280.00
Comments: Over 20 species of Herpetogramma have been described from North America that are based mostly on external morphology. The most recent treatment consolidates these into only nine species (Solis, 2010) and all nine occur in North Carolina.
Identification
Field Guide Descriptions: Online Photographs: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Adults: Solis (2010); Handfield and Handfield (2021)                                                                                  
Adult Markings: The adults have several color forms that range from pale gray with a yellowish hue on the forewing to predominantly dark brown, with the darker forms well-represented in North Carolina. Regardless of the general color, the head, palps, thorax, abdomen and dark colorings of the wings are concolorous. The marks on the forewing vary from medium to dark brown depending on the color form. The orbicular spot is dark and rounded or squarish, while the dark reniform spot is larger and either rectangular or curved inward. A white patch is present between the two spots, but not between the reniform spot and the postmedial line as seen in some of our Herpetogramma species.

The antemedial line is weakly sinuate and strikes the costa just anterior to the orbicular spot. The postmedial line projects inward from the costa at around three-fourths the wing length where it meets an outwardly bulged section with three blunt teeth. From there it projects basally towards the orbicular spot for a short distance, then sharply angles away after approaching the reniform spot and runs nearly perpendicular to the inner margin. A narrow, diffuse, pale line is present on the posterior margin of the postmedial line that contrast with a darker zone of dusting in the subterminal area. The forewing fringe can vary from light brown to dark brown, with a white region near the anal angle. There is a narrow, broken line at the base that parallels a brown marginal line that can be complete or weakly broken.

The hindwing is usually paler or whiter than the forewing, and the veins on the light forms often are dark and contrast with the paler ground color. There is an elongated discal spot and a postmedial line that is generally similar in shape to the one on the forewing. A whitish zone is present on the posterior margin of the postmedial line that is much more pronounced than the comparable pale zone on the forewing. It contrasts sharply with a darker zone of dusting in the subterminal area. The fringe on the outer margin is brown on the costal half and whitish on the tornal half, with a line of dark spots along the base of the brown region. The brown terminal line is well developed.

The dark forms of H. aeglealis are most easily confused with H. sphingealis. Both species have a white patch between the orbicular and reniform, but not between the reniform and the postmedial line. In the latter, the postmedial lines on both the forewing and hindwing are rather obscure and lack a pale or whitish zone on the posterior margin of the line.
Wingspan: 29–33 mm for males and 27–31 mm for females (Handfield and Handfield, 2021).
Adult Structural Features: Handfield and Handfield (2021) have descriptions and illustrations of the male and female genitalia.
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: The larvae feed on the foliage of ferns and herbaceous plants, and make shelters by folding and tying one or several leaves together, depending on the host plant. The larvae feed within the shelter and deposit their blackish frass in a large clump away from local feeding sites. The older instars have translucent, yellowish-green bodies with a dorsal and lateral row of yellowish-brown pinacula. The head is dull yellowish-brown above and the prothoracic shield has a blackish, dorsolateral patch on the posterior end. Pupation occurs within the shelter.
Distribution in North Carolina
Distribution: Herpetogramma aeglealis is found in eastern North America, including extreme southern Canada (Ontario; Quebec) and the U.S. from Maine southward to southern Florida, and westward to Louisiana, eastern Oklahoma, Missouri, eastern Nebraska, southern Minnesota and eastern North Dakota. This species occurs statewide in North Carolina, but is uncommon in the Coastal Plain where it is largely restricted to bottomlands and other mesic habitats.
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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