Household Casebearer (often confused with Plaster Bagworm)
Scientific Name: Phereoeca uterella (or sometimes Phereoeca allutella depending on region)
Order & Family: Lepidoptera: Tineidae
Size: Larval case length is typically 8-13 mm (approx. 0.3-0.5 inches)
Natural Habitat
Typically found indoors on walls, especially in corners, under furniture, or in humid environments like bathrooms and basements. They thrive in climates with high humidity.
Diet & Feeding
Larvae feed on old spider webs (contains silk and insect remains), keratin sources like wool or hair, dead insects, and fibers. They are detritivores.
Behavior Patterns
The larva constructs a flattened, pumpkin-seed-shaped protective case made of silk and debris (sand, soil, fibers), which it carries around. It has two openings, allowing the larva to feed from either end. When ready to pupate, it attaches the case to a vertical surface.
Risks & Benefits
Generally harmless to humans (does not bite or sting). Can be a minor household pest if they infest woolen clothing or rugs, though they typically prefer detritus like cobwebs. They benefit the ecosystem by cleaning up dead insect parts and old webs.
Identified on: 2/24/2026