The Moss's Elfin (also Stonecrop Elfin and Schryver's Elfin) (Callophrys mossii) is a butterfly native to North America that belongs in the family Lycaenidae. It is found from British Columbia south to southern California and east to Wyoming and Colorado in isolated populations. The habitat consists of rocky outcrops, woody canyons and cliffs. The larvae feed on Sedum (including Sedum spathulifolium and Sedum lanceolatum), Sedella, Dudleya and Parvisedum species. Young larvae feed on the leaves of their host plant. When older, they feed on the flowers and fruits.