Syllepte desmialis is a moth in the Crambidae family. It was described by Hampson in 1912. It is found in Nigeria. The wingspan is about 24 mm. The forewings have a subbasal hyaline point in the cell and quadrate antemedial spots in the cell, the latter with a spot below it. There is a lunulate mark just beyond the cell composed of five almost conjoined spots between veins 3 and 8, the two middle ones larger. The hindwings have an oblique dark medial line ending above the tornus and a quadrate discoidal hyaline spot with a short dark line on its outer edge.