Small Scarab Fly
Small Scarab Fly
Small Scarab Fly (Osa sp)Class: Animals (Animalia) - Jointed Legs (Arthropoda) - Insects (Insecta)
Order: Flies (Diptera)
Family: Pyrgotid Fly (Pyrgotidae)     iNaturalist Observation
Species: Small Scarab Fly (Osa sp)
This Photo:     Ovipositor
Other name: Light Fly

Thank you Tony Daley for confirming the id of this species for us

General Species Information:
Found on Ellura (in the Murray Mallee, SA) and elsewhere
~10mm long (excluding the ovipositor).
Had lots of them at the night light, along with many smaller beetles (assume scarab). You could well think that with the ovipositor it's a fruit fly. But no, a related family, Pyrgotidae, also called Light Flies as they come to night lights. Scarab flies because they parisitise scarab beetles. Very distinctive head shape, but couldn't get the wings veins very clearly. The body hair is diagnostic for this genus. Looking at Facilina sp, the hairs are tiny in comparison.
Tony said "Osa nr. bornemisszai, a WA species. Seems very close - I end at this species following Paramonov's key (1958) but alas the description within doesn't fully agree, the palps being yellow and the ovipositor black with only middle portion brownish in that species (thus distinctly black basally). Form of the ovipositor and wing spotting seems the same or similar."
Here you can see the palps are black and the ovipositor is brownish, with a black tip.
As an explanation "nr." is an abbreviation for "near". As in, it's close to O. bornemisszai, but isn't that species. This can be construed as "further away" than a "cf" annotation; which means "looks like" and so maybe that species, but not enough diagnostic features are shown or clear enough.

Copyright © 2017-2024 Brett & Marie Smith. All Rights Reserved. Photographed 14-Dec-2017
This species is an Australian Native Species, not listed in the SA Murray Mallee Survey of 2010.