The adult and final instar larva are described and illustrated (holotype allotype $, paratypes: Punta Lara Forest and Laguna Chascomiis, Buenos Aires prov., 30-XI-1984). The new sp. is related to the ” didyma-hipodidyma-dythemoides-group” of CALVERT (1909, Ann. Carneg. Mus. 6: 73-20) and RIS (1911, Colins zool. de Sélys Longchamps 12: 385-527), but it is distinguished by the genitalia. wing venation and pattern of thoracic and abdominal coloration.