The borer beetle Hedypathes betulinus, plague of "erva-mate" (Ilex paraguariensis St. Hil., 1822), has been subject of study aiming its biological control. Larvae of this insect digs galleries in the stem and branches of this tree, difficulting its control. Labena fiorii sp.n. was found in branches of this tree, parasitizing larvae of Hedypathes betulinus in Teixeira Soares and in "aroeira" (Schinus sp.) in larvae of Chydarteres striatus (Fabricius, 1787) in Curitiba, Paraná, Brazil. Labena fiorii sp.n., from Paraná (Curitiba; Teixeira Soares) and Santa Catarina (Seara, Nova Teutônia) Brazil, is described.
Cerambycidae; Ichneumonidae; Labena fiorii sp.n.; erva-mate; aroeira