Household Casebearer (also known as the Phereoeca uterella or Plaster Bagworm)

Natural Habitat

Typically found indoors in humid climates, often in corners, under furniture, in bathrooms, closely observing fibers like wool, or hanging on walls.

Diet & Feeding

Larvae feed on old spider webs, silk, wool, human hair, pet fur, dead insect parts, and sometimes fibers from clothing or carpets.

Behavior Patterns

The larva builds a flattened, pumpkin-seed-shaped protective case made of silk and debris (sand, soil, insect parts) which it carries around. It can retract fully inside when threatened. It eventually pupates inside this case.

Risks & Benefits

Generally harmless to humans (does not bite or sting). Considered a minor household pest because they can damage wool or biological fibers, but they help clean up old cobwebs.

Identified on: 2/28/2026