Pseudacteon is a genus of flies in the family Phoridae. There are over 70 described species of Pseudacteon fly. They are also known as ant-decapitating flies due to their parasitic larval stage. An eg

The Phoridae are a family of small, hump-backed flies resembling fruit flies. Phorid flies can often be identified by their escape habit of running rapidly across a surface rather than taking flight.