Household Casebearer (often specifically the Plaster Bagworm or Phereoeca uterella)

Natural Habitat

Typically found indoors in warm, humid climates. They are often seen on walls (especially stucco or plaster), baseboards, and usually areas where spider webs and dust collect.

Diet & Feeding

Detritivores. They feed on spider webs, old insect skins, wool, hair, and other keratin-rich organic debris found in household dust.

Behavior Patterns

The larva constructs a flattened, pumpkin-seed-shaped protective case out of silk and debris (sand, paint, insect parts) which it carries around. It has openings at both ends, allowing it to turn around inside and feed from either side. It drags this case along walls and floors.

Risks & Benefits

Generally harmless to humans (they do not bite or sting). However, they can be a minor nuisance pest in homes. Since they feed on spider webs, they can remove some cobwebs, but large infestations may indicate a need for better cleaning or humidity control.

Identified on: 2/20/2026