Polygrammodes supremalis is a moth in the Crambidae family. It was described by Schaus in 1920. It is found in Brazil (Paraná). The wingspan is about 43 mm. The base of the forewings, except the edge of the costa and inner margin broadly to the postmedial line, is fuscous brown shot with iridescent steel. This dark area is edged in front by a fuscous brown line preceded by a dark yellow line. An angled dark yellow line edged with fuscous brown is found medially on the inner margin and the postmedial area is pale brown. The medial pale yellow area forms a large irregular triangle with its base on the costa. There is a small spot in the cell, defined by some dark scales and there is a yellow streak on the discocellular, edged by a reddish brown line. The costa is yellow to the apex, only cro