Two different instars of Oxelytrum lineatocolle larva are morphologically described and for the first time reported found in corpses. We suggest using the relationship between length segments of urogomphs to identify instars. In addition, four characters of mature larvae of genre Oxelytrum are described, allowing three species to be differentiated in Neotropical region. The forensic utility of these or other carrion beetle larvae depends on correct identification of species and instars.