The pupal case of the Nearctic robber fly Proctacanthus brevipennis (Wiedemann, 1828) is described, illustrated, and compared with those of P. hinei Bromley, 1928; P. micans Schiner, 1867; P. milbertii Macquart, 1838; P. philadelphicus Macquart, 1838; and P. rufus Williston, 1885. A revised key is provided to the pupal cases of these species. Observations are reported on emerging adults and a newly emerged female P. brevipennis being captured and eaten by a green anole, Anolis carolinensis (Voigt, 1832).