The minute black scavenger flies or "dung midges", are a family, Scatopsidae, of nematoceran flies. Despite being distributed throughout the world, they form a small family with only around 250 described species in 27 genera, although many await description and doubtless even more await discovery. These are generally small, sometimes minute, dark flies (from 0.6 to 5 mm), generally similar to black flies (Simuliidae), but usually lacking the humped thorax characteristic of that family.