Apodemia mormo langei, the Lange's metalmark butterfly, is an endangered North American butterfly. It is a subspecies of the Mormon metalmark and belongs to the family Riodinidae. The butterfly is endemic to California, where it is known from one strip of riverbank in the San Francisco Bay Area. A 2008 count estimated the total remaining population at 131 individuals. Since 2011, this number has dropped to about 25–30.