Moths of North Carolina
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View PDFCossidae Members:
Prionoxystus Members:
114 NC Records

Prionoxystus robiniae (Peck, 1818) - Carpenterworm Moth

Taxonomy
Superfamily: Cossoidea Family: CossidaeSubfamily: CossinaeTribe: [Cossini]P3 Number: 640029.00 MONA Number: 2693.00
Comments: One of three members of the genus in North America, two of which are found in North Carolina. It is among the largest of the "micro-moths."
Identification
Field Guide Descriptions: Covell (2005); Beadle and Leckie (2012)Online Photographs: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Adults: Forbes (1923)Technical Description, Immature Stages: Packard (1890)                                                                                 
Adult Markings: Sexually dimorphic. Both sexes possess a thick abdomen, broad thorax, and disproportionally small head with pectinate antennae. The forewings of the female are black and heavily mottled with black-centered gray spots and blotches, while the hindwings are translucent gray. Males are smaller with narrower, more attenuated forewings that show similar markings but appear noticeably blacker overall. The hindwings of the male have a straighter outer margin and are reddish-orange to yellow, bordered in black. Differentiated from P. macmurtrei by less translucent gray-spotted rather than black-striated forewings.
Wingspan: 50-75 mm (Forbes, 1923)
Adult Structural Features: Length from tip of head to apex of forewing at rest averages 44.5 mm (n=2) (female).
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: The larvae are known as carpenterworms for their wood-boring habits. Early instars are reddish-pink with dark brown thoracic segments and heads. Last instar is large (up to 3 inches) and greenish-white, with pink shading, raised reddish bumps along the dorsum and sides, reddish, oval spiracles, and a dark brown head and thorax. Because they develop in wood, larvae are rarely seen, although the exit holes can be seen scarring tree trunks. This species can be a serious pest in ornamental or agricultural settings.
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.
Distribution in North Carolina
Distribution: Probably occurs statewide
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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