Plaster Bagworm (Case-bearing Moth Larva)
Scientific Name: Phereoca uterella
Order & Family: Lepidoptera: Tineidae
Size: Case is typically 8-13 mm in length; the larva inside is smaller.
Natural Habitat
Commonly found in humid subtropical climates inside homes, particularly on walls, floors, and under furniture.
Diet & Feeding
Larvae feed primarily on spider webs, but also consume wool, silk, and organic debris like human hair it finds in the environment.
Behavior Patterns
The larva constructs a silken protective case covered with sand, soil, and floor debris. It can retract its head into either end of the spindle-shaped case to feed or move. It undergoes several molts before pupating within the same case attached to a wall.
Risks & Benefits
Generally harmless to humans and pets, but can be a minor household pest if they damage silk or wool fabrics. They are mostly an aesthetic nuisance, and their presence often indicates high humidity or an abundance of spider webs.
Identified on: 4/24/2026