any of a group of delicate butterflies in the family Nymphalidae (order Lepidoptera) that are abundant during summer months in the woods and grasslands of the United States and Europe. The adults are dull brown or grey, while the larvae possess small, forked tail-like appendages on their abdomens. Adult butterflies have brown wings with a span of 5 to 6 cm (2 to 2.4 inches) and conspicuous circular markings on them. These false “eyes” on the wings may serve to frighten or distract predatory birds.