Cissia eous, locally known as the brown butterfly (), is a butterfly in the family Nymphalidae described by Arthur Gardiner Butler in 1867. It is found in the countries of Brazil, Argentina, Uruguay and Paraguay.

Biology and phenology: In the moist and shady habitats of several vegetal formations, like secondary forests and coastal forest edges in Brazil, you´ll frequently find adults of this species. They´re attracted to fermented fruits and other decaying materials.

Larvae of this species can feed on Poa plants. Specifically in Poa annua, Digitaria sanguinalis and Stenotaphrum secundatum.