---

I think I have found them on rotten tree trunks with Crabro holes. Here are a few references
Eustalomyia festiva Zett, Hennig, 1966-76, reared from pupa of Agrotis (Lepidoptera),
Eustalomyia sp, Hennig, 1966-76, in nests of wasps (in dead wood) of subfamily Crabroninae; feeding on food store of paralysed insects (kleptoparasites).,
Eustalomyia sp, Smith, 1971,
Eustalomyia sp, O'Toole, 1978, host records,