dipteran mating display?

[Ken Kinman]

Robin and Herb,
      Thanks for the feedback.  I looked at some photographs of Bibionids, and the ones I saw seem to have much shorter antennae than my gnat.  And it's more of a dark grey (not black).  Couldn't find any Empidids that matched either.

      One striking thing about the posterior pair of legs (which it is holding above its body) is that each leg has two prominent spines.  The spines are pointed posteriorly when the legs are held above the body.  I guess these spines would be directed downwards (or even somewhat anteriorly) when the legs are in the "normal" insect position, but I can only get it to lower that pair of legs VERY briefly by knocking it off balance.  Otherwise that pair of legs springs right back up above the body as though it were trying to threaten me.  It's head is very small.   I wonder if it could be a fungus gnat of some kind??  Will have to look at more gnat photographs tomorrow.
        ------- Ken