Pycnarmon peruvialis is a moth in the family Crambidae.

There is an antemedial black point in the cell and discoidal striga, the latter with a slight black-brown annulus above it on the costa, as well as a faint brownish-ochreous line from the origin of vein 2 to the inner margin.

There is also a brownish-ochreous shade beyond the cell and an ochreous-brown postmedial line with two black-brown striae at the costa.

The hindwings are silvery white with a black discoidal bar, a postmedial line with a black spot at the costa, which then becomes brownish ochreous.

There is also a blackish striga on vein 3 before the termen and a slight ochreous-brown terminal line.