Blunt March Fly
Male, anterior
March Fly
S6, Female, dorsal
March Fly (Dasybasis sp)Class: Animals (Animalia) - Jointed Legs (Arthropoda) - Insects (Insecta)
Order: Flies (Diptera)
Family: Deer Fly (Tabanidae)     iNaturalist Observation
Species: March Fly (Dasybasis sp)
This Photo:     S5, Female, dorsal

Thank you Tony and Jenny Dominelli for confirming the id of this species for us

General Species Information:
Found on Ellura (in the Murray Mallee, SA), the Adelaide Hills and elsewhere
Oh my; they were really bad this year (end 2014). We couldn't walk 100m through the bush without being attacked.
Typically they appear in March (hence their name) but the favourable weather conditions (hot & dry winter) saw them out in spring.
They are a large and moderately attractive fly (if there is such a thing
, with gentle grey to brown strips.
The eyes on the male are touching, where as the females have a large gap, which is visible with the naked eye.
The females are the only ones that bite, feeding on the blood of animals (including humans). They lay in wait in a cool bush (senna, acacia, etc) waiting for prey to come past, then they pounce. Once they have your scent they won't leave you alone until they've fed (bitten you) or you've killed them.
Sorry, but anything that bites us isn't safe from us, even if it is native.
They are robust and we've hit them and they've fallen to the ground unconscious. They've then woken up and attacked again.
They have a preference for the back of your legs, but will bite through clothing on your back or rump (very painful for some reason).
While not as painful as a bee sting, it is as bad as an ant bite.
Long trousers & baggy clothes are the order of the day, with a good dose of personal insecticide to be safe.
While we can't be sure, it's possible the males buzz overhead, distracting you, while the females attack your legs. The fact they hide by biting you from behind suggests they have some understanding of where you are looking / facing. They rarely seem interested in arms, and walking fast seems to stop them biting (but not following; you have to stop at some point). So perhaps they don't like movement.

Copyright © 2015-2024 Brett & Marie Smith. All Rights Reserved. Photographed 26-Feb-2015
This species is an Australian Native Species, not listed in the SA Murray Mallee Survey of 2010.