Notocrypta curvifascia, the restricted demon, is a butterfly belonging to the family Hesperiidae. N. curvifascia is commonly found in many regions of temperate and tropical East Asia, Indonesia, and the Indian subcontinent, wherever its preferred larval host plant, Alpinia nutans can be found. Among butterflies, it is relatively small, at approximately 4 cm long (adult). Its wings are dark brown to black, with a white eyespot near the trailing end.