Collected a number of these, both males and females, at UV light. Six were collected on this date.
I think it may be Atherigona sp. (or something similar). It doesn't look quite like the one species of Atherigona (A. orientalis) listed for nearctic in (1)
based on comparison to images on the web.
Edit: I see that another species, Atherigona reversura, has been reported from Georgia and Florida. I wonder if this could be it.