Explanation of Names
Species name unio is Latin for "onion" or "large pearl". The latter seems to be the context. (Based on Internet searches.)
Identification
Adult: dark band along outer margin of forewing is scalloped on the inside.
Range
Eastern and central North America
Habitat
Fields, edges, presumably.
Season
adults fly June-August and later into fall in south
Food
Larvae feed on Evening-primrose, grapes, other herbs.
Adults probably do not feed.
See Also
Beautiful Wood-Nymph (
Eudryas grata) dark band along outer margin of forewing is smoothly curved on the inside
Compare E. unio/E. grata:
Internet References
Lynn Scott, Ontario live adult photos, description, foodplants, flight dates
Georgia Leps pinned adult image (James Adams, Dalton State College)