In Missouri, giant robber flies of the genus Promachus are commonly found on limestone/dolomite glades scattered throughout the Ozarks. This individual was seen in the "White River Hills" region of southwestern Missouri after capturing one of the so-called "small carpenter bees" in the genus Ceratina (Hymenoptera: Apidae) [ID by Mike Arduser, Missouri Dept. Conservation].

As I understand it, there are three "tiger-striped" species of Promachus in the eastern U.S., with P. hinei being the most common in the central U.S. It is distinguished from the more southern P. rufipes by the reddish rather than black femora and from the more northern P. vertebratus by the larger dark areas dorsally on the abdominal segments and distinctly contrasting two-toned legs.

Full-size image and more comments can be found at my website in the post, Prey bee mine.