The leaf-cutting ants Atta sexdens (Linnaeus) and Atta laevigata (Smith) were parasitized by the following phorid flies: Apocephalus attophilus Borgmeier, Apocephalus vicosae Disney, Myrmosicarius grandicornis Borgmeier and species of Eibesfeldtphora Disney. It is also related here that the area of occurrence of phorids parasitizing A. sexdens was extended to include Central Brazil. The rate of parasitism on A. sexdens was three times lower than the rate found on A. laevigata; most common flies were, respectively, M. grandicornis in A. sexdens and A. attophilus in A. laevigata. This last phorid showed the shortest life span but the higher percentage of emergence. Multiparasitism on workers of A. sexdens and of A. laevigata involving three combinations of four phorid species was rare and is here related for the first time for leaf-cutting ants.

RESUMO Este estudo relata a primeira ocorrência de Pachycrepoideus vindemmiae (Rondani) (Hymenoptera: Pteromalidae) como parasitóide de Ornidia obesa Fabricius (Diptera: Syrphidae) encontrado em fezes de galinhas em Itumbiara, Goiás, Brasil. Amostras de fezes foram coletadas em intervalos de duas semanas de sua exposição, levadas para o laboratório para extração das pupas pelo método de flutuação. As pupas foram individualizadas em cápsulas de gelatina e mantidas até a emergência dos dípteros e/ou parasitóides. A porcentagem de parasitismo foi de 9%.