BTW, this is a female...you can tell from the "theca" jutting out from below the 5th sternite in your 2nd image. In subgenus Pachyconops of Physoconops (which this is) the theca of females is often quite noticebly longer than that in Physocephala (as are the 3rd antennal segments). The theca is used to help grasp and pry open the tergites of the unfortunate bee or wasp host as the conopid attempts to insert an egg...all done while in flight!! (Or perhaps after tumbling to the ground.)

Also, if you get the opportunity, try to get a frontal shot of their faces, which give lots of diagnostic characters for ID. I know it's often difficult, because they're more likely to flee when you approach closely from the front...but if they're engrossed in feeding on a flower, and you first stalk gingerly from the back or side...then slowly circle around to view the face, it's sometimes do-able. (Especially if you get a cooperative one :-)