Pseudacteon formicarum is a kind of parasitic species of flies from the family of Phoridae of the subfamily Metopininae.
Pseudacteon formicarum is found in Europe, and is parasitic on the ants Lasius alienus, Lasius niger, Lasius emarginatus, Lasius flavus, Lasius fuliginosus, Formica sanguinea, Myrmica lobicornis, Tapinoma erraticum and others.