Ethmia heptastica is a moth in the family Depressariidae. It is found along the west coast of Mexico, from Sonora and Sinaloa south to Cuernavaca and northern Guerrero.
The length of the forewings is . The ground color of the forewings is divided by a longitudinal line along. The costal half is dark brown, the line forming two irregular, square spurs of dark from the cell into the pale dorsal area at the basal one-fourth and the middle. The ground color of the hindwings is uniform dark brown. Adults are on wing in June, July and August.[1]