In general, adult flies are medium to small, slender flies with green, blue or copper metallic colored bodies and long legs. Their wings are clear or marked with darker areas towards the wing tips. Wing venation patterns are characteristic for identification to family. The males often have enlarged genitalia which can be useful for species recognition. The adults are predatory on other small animals. The larvae occupy a wide range of habitats, both terrestrial and aquatic, and can be predators or scavengers.
They are common in lightly shaded areas near swamps and streams, in meadows and woodlands, and our yards.