Thaumatopsis pectinifer

Distinguished from other Thaumatopsis species by genitalia morphology; external identification requires expert examination. The combination of small size, grassland habitat, and North American central plains distribution helps narrow possibilities.

Small moth with wingspan 19–22 mm. Forewings and hindwings are narrow, typical of Crambinae grass moths. Coloration not explicitly described in sources.

Grassland habitats, including prairies and agricultural fields. Associated with host grasses in open, sunny environments.

North America: recorded from North Dakota south to Oklahoma and Texas, east to southern Florida, north to Michigan and Indiana. Covers the Great Plains and parts of the Midwest and Southeast.

Adults active March, May–June, and August–November. Multiple generations per year suggested by flight period pattern.

Larvae feed on various grasses (Poaceae), including Zea mays (corn). They bore into stems of host plants.

• Zea mays - larval hoststem borer
• Poaceae - larval hostvarious grasses

Complete metamorphosis. Larvae are stem borers in grasses. Pupation presumably occurs in soil or within host stems, though not explicitly documented.

Adults are nocturnal. Larvae bore into grass stems, feeding internally.

Herbivore in grassland ecosystems. Potential minor pest of corn.

Minor agricultural pest of corn. No major economic impact documented.

• Other Thaumatopsis speciesSimilar size, habitat, and appearance; require genitalia dissection for definitive identification
• Other Crambinae grass mothsShared grassland habitat and grass-feeding larval ecology; external morphology often convergent

• grassland
• stem borer
• agricultural pest
• North America

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• Catalogue of Life