Catocala relicta, the white underwing or relict, is a moth of the family Erebidae.

[1][2] It lives in southern Canada, from Newfoundland to Vancouver Island, south to Missouri, and Arizona.

Adults are on wing from July to September in one generation depending on the location.

The larvae feed on Betula papyrifera, Carya ovata, Populus alba, Populus balsamifera, Populus deltoides, Populus nigra, Populus tremuloides, Quercus species, and Salix species (including Salix eriocephala).

Catocala relicta elda, recorded from Oregon, was formerly considered a subspecies, but is now thought to be a synonym of Catocala relicta.