Rearing of Chrysomya megacephala (F.) and Chrysomya rufifacies (Macquart) in pure cultures at seven different population densities (larvae per gram of liver) demonstrated an inverse relationship between density and the duration of the larval stage. In pure cultures, larval mortality rates decreased with increasing density until an optimum density was reached (8 larvae/g liver for C. megacephala and 10 larvae/g liver for C. rufifacies), then decreased directly with density. Puparial and adult weights varied inversely with density for both species in pure cultures. Internal feeding mass temperatures were above ambient temperatures for all cultures, with maximum temperatures recorded in cultures with 20 and 40 larvae/g liver for G. rufifacies and C. megacephala, respectively. In paired encounters, larvae of C. rufifacies were cannibalistic and predatory on C. megacephala larvae after the first instar. In mixed cultures of these two species, the larval mortality of C. rufifacies remained relatively stable, whereas the larval mortality of C. megacephala increased directly with population density.

Larvae of the flesh fly, Boettcherisca peregrina (Robineau-Desvoidy), were reared on the tissue of rabbits to study the effects of cocaine and benzoylecognine on development rates. The rabbits were given 35, 69, and 137 mg of cocaine through cardiac puncture. From hours 30 to 70, larvae developed more rapidly on tissue containing cocaine, benzoylecognine, or both, from rabbits injected with 69 and 137 mg of cocaine than on tissue from rabbits injected with 35 mg of cocaine or no cocaine. Total development times required for pupation and adult eclosion were shortened correspondingly. Differences observed in the rate of development were sufficient to alter postmortem interval estimates based on larval development in decomposing human tissues by up to 24 h.