During studies on tabanids (horse-fly) populations on Marambaia Island, Rio de Janeiro, Brazil, the authors collected specimens of robber flies, which are predatory flies belonging to the dipteran family Asilidae. Robber fly species were identified as Lecania leucopyga (Wiedemann, 1828), Mallophora calida (Fabricius, 1787), Triorla striola (Fabricius, 1805) and an undetermined specimen of Taurhynchus genus. Lecania leucopyga (Wiedemann, 1828) and Triorla striola (Fabricius, 1805) are recorded for the first time in Rio de Janeiro state, Brazil.
