Household Casebearer (or Plaster Bagworm)
Scientific Name: Phereoeca uterella
Order & Family: Order: Lepidoptera, Family: Tineidae
Size: Approximately 8-13 mm (0.3-0.5 inches) in length.
Natural Habitat
Typically found indoors in dry, dusty environments. Common on walls, in closets, under furniture, or in spider webs found in garages and basements.
Diet & Feeding
Larvae feed on detritus, including spider webs, old insect skins, wool, animal hair, and lint. They are detritivores.
Behavior Patterns
The larva constructs a flat, pumpkin-seed-shaped protective case from silk, sand, and debris, which it carries around. It can extend its head from either end of the case to move or feed.
Risks & Benefits
Generally harmless to humans (does not bite or sting). Can be a minor pest to wool clothing or rugs, but mostly considered a nuisance pest due to their appearance on walls.
Identified on: 3/1/2026