Hahncappsia marculenta is a moth in the Crambidae family. It was described by Grote and Robinson in 1867. It is found in North America, where it is widespread east of the Rocky Mountains. The wingspan is 18-24 mm for males and 21-26 mm for females. The forewings are pale yellow with luteous markings. The hindwings are paler yellow. Adults have been recorded on wing from May to September. The larvae feed on Ambrosia trifida and Solidago species.