Mydas fly

The Mydidae (alternative spelling Mydaidae), or Mydas flies, are a cosmopolitan family of flies. It is a small family, with about 471 species described. They are generally large in size, including, in fact, the largest known fly, Gauromydas heros (syn. Mydas heros). Many of the species, in addition to their large size, are mimics of stinging hymenopterans, especially wasps. Most mydids are found in arid and semiarid regions of the world, but they are also found in other habitats. They are infrequently encountered as the adult lifespan can be quite short. Little is known about their biology, though Zikan reported the larvae of Gauromydas heros live in the subterranean detritus "pans" of Atta ants in southern Brazil, where they appear to be feeding on detritivorous Dynastinae (Coelosis spp.) larvae. In the U.S., Mydas brunneus, Mydas clavatus, and Mydas tibialis larvae are predatory on deadwood-feeding scarab beetle larvae (Osmoderma spp.) and can be found in standing and downed trees with extensive heart rot. Others (e.g. Mydas maculiventris) are subterranean and feed on "white grubs" (Scarabaeidae: genus Phyllophaga) that attack the roots of grasses and could be potential biocontrol agents of white grubs in sod production areas. Larvae typically take 2–3 years to mature. Adults of several species are avid flower visitors and act as pollinating agents. Rattlesnake master (Eryngium yuccifolium) is a favorite nectar source in the Midwest.