ABSTRACT
The most recent revision of North American blow flies was by Hall; however, Hall’s keys have proven to be difficult to use because of his heavy reliance on proportional measurements of characters and the fact that he measured no more than five to ten specimens per species. He also chose specimens representing size extremes rather than “average” individuals. Many blow flies were personally collected with the aid of bait traps baited with carrion. The keys are written for the identification of dry, pinned specimens. With the advent of deoxyribonucleic acid analysis, many specimens are collected in alcohol, or other liquids, which discolors and warps specimens, often making identification more difficult. As of 2017, there are 93 species and 19 genera of Calliphoridae known in North America. The largest genera include Protocalliphora with 28 species, Calliphora with 18 species, and Lucilia with 12 species.
