Hexyl butyrate and (E)-2-hexenyl butyrate, common metathoracic scent gland compounds of plant bugs (Heteroptera: Miridae), attracted large numbers of female chloropid [Olcella trigramma (Loew), O. cinerea, Conioscinella sp.] and milichiid (Leptometopa latipes Meigen) flies. Blends of these two butyrates attracted significantly more chloropids than did the compounds individually. The optimal synergistic ratios for O. trigramma attraction ranged from 1:1–9:1 hexyl butyrate to hexenyl butyrate. These values are similar to natural ratios of the compounds in the scent gland secretion from tarnished plant bugs, Lygus lineolaris, and other mirids. Antennae of female O. trigramma gave strong electrophysiological responses to (E)-2-hexenyl and hexyl butyrates, whereas electroantennogram responses to butyl butyrate and pentyl butyrate were insignificant. (E)-2-octenyl acetate, one of the major sex pheromone components of mirids in the genus Phytocoris, was strongly attractive to the milichiid, L. latipes, and another pheromone component of Phytocoris bugs, hexyl acetate, was inactive alone, yet synergized the attraction of the milichiid and three chloropid species to (E)-2-octenyl acetate. Traps baited with (E)-2-hexenyl (E)-2-hexenoate, a volatile component of various heteropterans, were significantly attractive to both O. cinerea and L. latipes, whereas addition of γ-caprolactone and green leaf alcohols significantly reduced the numbers of both fly species caught. Our results suggest that females of these chloropid and milichiid flies use volatile defensive and pheromonal compounds from plant bugs as kairomones to find freshly injured or dead bugs on which to feed. The sex-specific attraction might indicate that females of these flies need a protein-rich meal for maximum fecundity, as do anautogenous mosquitoes.