This stunner is a Dance Fly in the Empididae family which is a large one in the US. There are over 760 species and this genus, Rhamphomyia, has over 150 in it. Note the decorations on the legs and the large proboscis with a folded look. Those impressive red eyes are visible without effort and even in flight. Many of these fly together in groups in up-and-down movements and thus the name Dance Flies. Females in some species have inflatable sacs on the abdomen that lure males, presumably imitating an egg-laden (and receptive) state.

Another Dance Fly which may not be in the Rhampomyia genus. It was working the pollen on this pussytoe flower vigorously in March 2006. Impressive beaks on these things.