Cissia eous, locally known as the brown butterfly (Brazilian Portuguese: borboleta marrom), is a butterfly in the family Nymphalidae described by Arthur Gardiner Butler in 1867.

[1] It is found in the countries of Brazil, Argentina, Uruguay and Paraguay.

[1] 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.

[1] They're attracted to fermented fruits and other decaying materials.

[3] Specifically in Poa annua,[4] Digitaria sanguinalis and Stenotaphrum secundatum.