Household Casebearer (also known as the Plaster Bagworm)
Scientific Name: Phereoeca uterella
Order & Family: Order: Lepidoptera, Family: Tineidae
Size: The case is typically 8-13 mm long; the larva inside is slightly smaller.
Natural Habitat
Commonly found indoors on walls, baseboards, and ceilings, particularly in humid climates. They are often noticed in closets, bathrooms, and garages.
Diet & Feeding
The larvae feed on old spider webs, silk, wool upholstery, hair, lint, and dead insects. They are detritivores.
Behavior Patterns
The larva constructs a flattened, pumpkin-seed-shaped protective case out of silk and camouflages it with sand, soil, lint, and debris. It drags this case along as it moves. Before pupating, they often attach their case to a vertical surface like a wall.
Risks & Benefits
Generally considered a harmless nuisance rather than a major pest. They do not bite or sting humans. While they can feed on woolen fibers, they usually prefer spider webs and general house dust, meaning they rarely cause significant damage to clothing compared to clothes moths.
Identified on: 3/7/2026