Prorasea simalis is a moth in the Crambidae family. It was described by Grote in 1878. It is found in North America, where it has been recorded from Alberta, California, Colorado, Nevada and Oregon. The wingspan is 22 mm for males and 26-29 mm for females. Adults are variable in colour, ranging from ochereous to fuscous or blackish. There are indistinct oblique lines on the forewings, flecked with white. The median lines are dark, the subterminal area is fuscous or ochereous and the subterminal shade is white. The hindwings are smoky fuscous, but paler at the base. Adults have been recorded on wing from March to August.