The identification of insect species involved in corpses decomposition is of particular importance in estimating the post-mortem interval (PMI) in forensic science, since the PMI is based on information about the life cycle of necrophagous insects. However, the identification of some insect species, especially in their immature stages, may be complicated by many factors, even for experienced taxonomists. Species of the same genus such as Hemilucilia segmentaria (Fabricius) and H. semidiaphana (Rondani) (Diptera: Calliphoridae) are morphologically and behaviorally very similar, but differ in their growth and maturation rates. These species are abundant in forests, exclusively necrophagous and, therefore, are of potential medicolegal importance for estimating the PMI in criminal events that would take place in those areas. 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