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Any of several moths of the family Psychidae, the larvae and females of which inhabit fibrous cases constructed of silk with bits of leaves and other debris, especially Thyridopteryx ephemeraeformis, a pest of deciduous and evergreen trees.
1. (Animals) the larva of moths of the family Psychidae, which forms a protective case of silk covered with grass, leaves, etc
2. (Animals) bagworm moth any moth of the family Psychidae
any moth of the family Psychidae in its caterpillar phase, in which it wraps itself in a bag of silk, leaves, etc.