Malaise trapping efforts for Therevidae (Diptera: Asiloidea) have uncovered a relationship between brachyceran Diptera and mites of the family Microtrombidiidae (Acarina: Trombidioidea). Malaise trap samples from a Juniperus forest in McKinley County, New Mexico produced 39 brachyceran families, 14 of which were parasitized by microtrombidiid mites in the genera Platytrombidium Thor and Microtrombidium Haller. The frequency of parasitization was significantly higher in Tachinidae and Therevidae than the other 12 brachyceran families with parasitized individuals. Mite loads, i.e., the number of mites per individual, were also statistically different among families; some individuals were parasitized by as many as 21 mites. Mites preferred to attach at sites with soft, weakly sclerotized cuticle; the ventral cervical area and the membrane behind the hind coxae were most densely infested. Female Therevidae were attacked by mites at a significantly higher frequency than their male counterparts, but mite loads were similar. Insights into the host-parasite relationships between the flies are discussed, but the paucity of both mite and dipteran information limits their interpretation.