Wingspan 15-20 mm. One of the larger of the Coleophoridae, this species has a metallic green sheen to the forewings. The comparatively large size, metallic green forewings with copper apex and white tip to antennae, make this species one of the few which cane be identified without recourse to dissection of the genitalia, although the differences in size between this and other related species may only be obvious in series of mounted, set specimens. Larva feeds within seedpods of Ribbed Melilot and Tall Melilot, living within a movable case. The adults fly in the daytime, but are also attracted to light at night.
It occurs in areas of open waste ground and grassland, and is on the wing in June and July.