Parasitic Natural Regulatory Agents Attacking Musca domestica L. in Puerto Rico

Abstract
Immature stages of Musca domestica L. were sampled in Puerto Rico during 1903 for the purpose of securing parasitic material for use in biological control work in California. Six hymenopterous parasites were discovered in more or less stable breeding sites. One undescribed species of Diapriidae, Trichopria sp., and five Pteromalidae, Spalangia endius Walker, Spalangia nigroaenea Curtis, Spalangia slomoxysiae Girault, Muscidifurax raptor Girault and Sanders, and Pachycrepoideus vindemmiae (Rond.) were involved. Parasitization at any given collection site ranged from 1.4 to 25 percent of viable pupae. The Central and West Central Sections of the Island showed highest parasite activity. The role of predators other than ants was thought to be of prime importance in natural control of the more advanced immature stages of houseflies.