Tarsocera cassina, the sand-dune widow, is a butterfly of the family Nymphalidae. It is found in South Africa in the Western Cape along the coast from Lambert's Bay to Bredasdorp.
The wingspan is 35âÂÂ40 mm for males and 40âÂÂ45 mm for females. Adults are on wing from September/October to November. There is one generation per year
The larvae feed on various Poaceae species, including Lolium species and Brachypodium distachyum.