Household Casebearer (Plaster Bagworm)

Scientific Name: Phereoeca uterella

Order & Family: Order: Lepidoptera, Family: Tineidae

Size: Case length is about 8 to 14 mm; the larva inside is smaller.

Typically found inside houses, building walls, and high humidity areas where silk-spun cases can hang.

Larvae feed primarily on spider webs, wool, and natural fibers like silk or hair.

Larvae live inside a flattened, diamond-shaped silk case covered in sand and dust; they can protrude their heads from either end to move or feed.

Generally harmless to humans but can be a minor nuisance pest by damaging natural fiber clothes or household fabrics.

Identified on: 5/18/2026