Abstract: Larval spiracle morphology of Parasarcophaga crassipalpis (Macquart) was studied in detail under microscope, and the corresponding morphological indexes were collected and analyzed by digital image processing equipment. The results showed that structural traits of anterior and posterior spiracles regularly changed along with larval growth. When the 2nd and 3rd instars overlapped, special morphological features occurred. This stage could be an ideal age indicator to determine the decisive time for possible use in forensic entomology. Measurements of the ratio of length and width of anterior spiracle chamber and the average optical density of anterior and posterior spiracles were confirmed as larval age markers. This study further confirms the correlation between morphological indexes and postmortem interval as long as the investigator accounts for the development data of the species.

Key words: Necrophagous flies, Parasarcophaga crassipalpis, larval morphology, postmortem interval, spiracle