Immature Forms

of Bagworm and Casebearer Moths


The immature forms in Psychidae and related families often attract more attention than the generally-drab adults. Larvae construct their cases from silk and from leaves, stems, cedar fruits, and other "found items" that provide camouflage. The head and thorax protrude from the case when the larva is on the move, but are quickly pulled inside in case of danger. Identifying immature forms, even to family, can prove difficult. Family Psychidae bears the common name bagworm moths, but other moths that build camouflaged bags or cases include moths in Tineidae, Mimallonidae, and Coleophoridae.

Pupation takes place within the same cases utilized during the larval period. After the pupal period the males take wing, but in most species in these families the female is wingless and never leaves the case. In a number of taxa the female lays her eggs in her case, so that eggs, larvae, pupae, and (female) adults are all protected by the case.

Casebearing in Lepidoptera has been compared with casebearing in the related order Trichoptera. One important difference is that casebearing larval caddisflies are aquatic.


Psychidae: Immature Forms, Bagworm Moth larvae and pupae

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