Aleochara taeniata Erichson, a staphylinid parasite of the house fly, Musca domestica L., was cultured in California after its introduction from Jamaica. Adults of the species are voracious predators of house fly eggs and young larvae. Eggs hatch in about 4 days in the laboratory, and larvae search actively through the substrate for fly pupae, the parasite-susceptible host stage. Pupae are entered through a hole gnawed in the puparium wall by the young larvae; the hole is closed with what appears to be fecal material. The 3 larval instars are ectoparasitic on the fly pupae within the puparium. Mature larvae emerge into the substrate where pupation occurs. Larval development requires 6-7 days, and pupal development another 14-16 days at 75°F. The total life cycle at this temperature approximates 25 days from egg to adult.