The Melissa Blue (Lycaeides melissa) is a butterfly of the Lycaenidae family. It is found in Western North America, from Canada to Mexico. The Karner Blue (Lycaeides melissa samuelis) is a subspecies of the Melissa Blue.
The wingspan is 22–35 mm. The butterfly flies from April to August depending on the location.
The larvae feed on Lupin, Medicago and Lotus species.