I love the Asilidae, and these tiny members (less than 10mm) are some of my favorites. According to BugGuide.net, members of this genera are known as “ogre gnats.” How mean! Just because someone has big crazy eyes and a hunchback… :)
I only saw a single one of these subjects this year; it was about a week and a half ago, on a clipped Zinnia stem, and I was unsure at first if it was even alive (it was, and naturally, I eventually, clumsily, scared it off). (But not before getting a couple decent shots.) Usually they come out in August; well at least in past summers. It’s been a weird year, of course. Not 100% positive, but pretty sure this is species Holcocephala calva.
Update: Thought I should add a “fuller view” of our little ogre friend. :)