Calephelis perditalis, the rounded metalmark or lost metalmark, is a butterfly in the family Riodinidae. It is found in Texas in the United States and Mexico, south to Venezuela. The species was first described by William Barnes and James Halliday McDunnough in 1918. The wingspan is 18–24 mm. The upperside of the wings is brown with indistinctly checkered fringes. There may be a dark median band. Adults feed on flower nectar, including the nectar of Chromolaena odorata. The larvae feed on Chromolaena odorata and Eupatorium glabratum.