The Melissa blue (Plebejus melissa) is a butterfly of the family Lycaenidae. It is found in western North America, from Canada to Mexico. The Karner blue (Plebejus melissa samuelis) is a subspecies of the Melissa blue, and was described by the novelist/lepidopterist Vladimir Nabokov. The wingspan is 22–35 mm. Below, the hindwing orange submarginal band, often with distal iridescent blue points, help to distinguish this species from the more muted colors and markings of the similar Plebejus idas. The marginal line is wider where the veins intersect. The fringes are not checked. The butterfly flies from April to August depending on the location. The larvae feed on Lupinus, Medicago and Lotus species.