Forensic use of Megaselia abdita and M. scalaris (Phoridae: Diptera): case studies, development rates, and egg structure.

Megaselia abdita Schmitz is reported from human corpses in 2 forensic cases in Chicago, IL. This fly has not been recorded in the Nearctic region before these occurrences. Descriptions of the death scenes and the insect indicators are given, as are developmental schedules and descriptions of the eggs of M. abdita and Megaselia scalaris (Loew). The presence of either fly on the body, together with blowflies or other insects, could contribute to a determination of the postmortem interval. Given their predilection for older carrion, these flies would be relegated to a secondary forensic role. Phoridae have been shown to be primary flies in Okinawa and Panama, and they may occur elsewhere as the only insect evidence, especially in sealed apartments inaccessible to large insects.