Abstract
The significance of the housefly,Musca domesticaLinnaeus, as a probably introduced species in the Western Hemisphere is pertinent to a search for more exotic natural enemies in the Eastern Hemisphere. Avenues of entry into this hemisphere are discussed. A list is provided of the principal larval and pupal parasites found by the authors attackingM.domesticain North, Central, and South America and this is compared to species from the Eastern Hemisphere.