Abstract Monthly parasitism rates and oviposition behavior of tachinid flies parasitizing Dichelops furcatus (F.) (Hemiptera: Pentatomidae) adults were determined. Weekly surveys, with duration of 2 hr each, were performed during 1 yr at the National Wheat Research Center in Passo Fundo, Rio Grande do Sul, Brazil. Stink bugs were collected from different plants and from crop residues, and taken to the laboratory to examine whether or not they were parasitized (presence of fly eggs). Number and egg allocation (dorsal and ventral surfaces) on stink bug bodies were determined. Stink bugs were kept inside plastic boxes to collect the parasitoid pupae and to identify the flies after emergence. Four tachinid (Diptera: Tachinidae) species were obtained as follows: Ectophasiopsis gradata (Wiedemann), Cylindromyia sp., and Gymnoclytia sp. 1 and sp. 2. The parasitism rate ranged from 2.5 to 7.0% (during Apr–Aug), and from 12 to 59% (Sep–Mar). Eggs were laid preferably on the dorsal surface (82%), and the majority of them (42%) under the wings. The number of fly eggs per parasitized stink bug ranged from 1.0 to 2.0. Resumo Taxa anual de parasitismo e comportamento de oviposicao de moscas tachinideos parasitando adultos de Dichelops furcatus (F.) (Hemiptera: Pentatomidae) foram determinados. Amostragens semanais, com duracao de 2 hr cada, foram realizadas durante 1 ano no Centro Nacional de Pesquisa em Trigo da Embrapa em Passo Fundo, Rio Grande do Sul, Brasil. Percevejos foram coletados em diferentes plantas e residuos de culturas agricolas e levados para o laboratorio onde foi determinado se os individuos estavam parasitados (presenca de ovos de moscas) ou nao. Numero e alocacao (superficie ventral e dorsal) dos ovos no corpo do percevejo foram determinados. Os percevejos foram mantidos em caixas plasticas para coletar as pupas dos parasitoides e entao identificar as moscas apos sua emergencia. Quatro especies de tachinideos (Diptera: Tachinidae) foram obtidos, sendo essas: Ectophasiopsis gradata (Wiedemann), Cylindromyia sp., and Gymnoclytia sp. 1 and sp. 2. A taxa anual de parasitismo variou de 2,5 a 7,0% (de abr-ago) e de 12 a 59% (de set-mar). Ovos foram preferencialmente ovipositados na superficie dorsal do percevejo (82%) e a maioria deles (42%) sob as asas. O numero de ovos das moscas por percevejo parasitado variou de 1,0 a 2,0. View this article in BioOne