It is an occasional pest of furs, flannel and similar materials, and has been inadvertently introduced to many places it is not originally native to.

In the male genitals, the clasper's harpe tapers from the base, but is generally slender, with a conspicuous swelling on the basal third of the costal part which distinguishes this species.

The anellus is generally not sclerotized (hardened), and the aedeagus is somewhat more robust than the other organs, though not large, curves slightly, and is somewhat expanded near the tip.

In the female genitals, the ostium is long and situated above two sclerotized horn-like swellings.

A record from Sri Lanka is more dubious; these individuals were described as a distinct species (Tinea pachyspila), but seem to be either P. allutella or the closely related and very similar plaster bagworm (P. uterella), which is sometimes also referred as "household casebearer".