Pycnarmon mallaleuca is a moth in the Crambidae family. It was described by Hampson in 1907. It is found in Brazil (Parana, São Paulo). The wingspan is about 20 mm. Adults are pure white, the forewings with some dark points on the costa and the lines are pale yellow-brown. There are traces of a discoidal spot. The hindwings have an indistinct discoidal spot and the postmedial line is excurved between veins 5 and 2, then retracted to below the end of the cell.