Plaster Bagworm (or Household Casebearer)
Scientific Name: Phereoeca uterella
Order & Family: Order: Lepidoptera, Family: Tineidae
Size: Larval case is generally 8 to 13 mm (0.3 to 0.5 inches) in length.
Natural Habitat
Typically found indoors in dry, humid areas such as closets, garages, and underneath furniture. They often attach to walls (including stucco and brick), baseboards, and carpets.
Diet & Feeding
Detritivores; larvae feed on spider webs, wool, old case fabrics, hair, lint, dried insect parts, and general household dust.
Behavior Patterns
The larva constructs a protective, flattened, pumpkin-seed-shaped case made of silk and debris (sand, soil, frass) in which it lives and carries around. It has openings at both ends of the case, allowing the larva to feed and move from either side. They often climb walls before pupating.
Risks & Benefits
Generally harmless to humans (they do not bite or sting). However, they are considered minor household pests because they can feed on woolen fabrics, rugs, and spider silk, potentially causing noticeable cosmetic damage if the infestation is large.
Identified on: 2/15/2026