Big Headed Fly, we believe

Subject: Is this a wasp?
Location: Coastal San Diego County
July 22, 2012 12:36 pm
Found this in my backyard in San Diego in mid July. It is 3/8” long. Can you identify it?
I’m guessing it’s a beneficial parasitic wasp of some kind?
Signature: Clint

Hi Clint,
This is most definitely not a wasp.  It is a fly.  We believe it is either a Big Headed Fly in the family Pipunculidae which is represented on BugGuide by a few species that look generally like your individual, though none are an exact match.  If it is not a Big Headed Fly, our second choice would be a Flower Fly or Hover Fly in the family Syrphidae, but there are too many possibilities for us to want to undertake that task after a long busy day at the day job and an evening of local activism regarding transportation issues.  Big Headed Flies and Syrphid Flies are grouped in the not taxonomically recognized category that is a between the Order and Family, though it is not considered a Suborder.  The insect diversity in Southern California is great, so we try to post unusual submissions from there whenever possible.