Abstract
Abstract Necrophagous blowflies are considered one of the most important evidence in legal investigations. Although similar in appearance, the various species differ in their evolutionary biology, ecology, and behavior. The correct identification of flies, especially of the family Calliphoridae, is the central to their use as evidence in forensic entomology. Samples were collected for six months in the year 2021 from some areas of the northwestern part of Libya, using a fly trapping net and baits, and since the area is located in the same climatic zone with no clear geographical barriers, we assume that the species of blowflies that were recorded in this key are likely to be found in the entire region. The key is provided to seven species of Calliphoridae: Chrysomya albicepis, Chrysomya megacephala, Calliphora vicina, Calliphora vomitoria, Pollenia sp., Lucilia sericata, Lucilia cuprina. With no clear database for forensic entomology species in Libya that were found or is likely to be found in the northwestern region of Libya, and with no identification key for these species; this key will represent the key stone for other forensic entomology studies. New forensic entomologists, researchers, or even students can easily use this key. Keywords: Calliphoridae, Calliphora, Pollenia, Chrysomya, Lucilia, North werstren Libya.