Species of Trichomalopsis (Hymenoptera : Pteromalidae) associated with filth flies (Diptera : Muscidae) in North America

Five species of Trichomalopsis Crawford associated with Haematobia irritans (L.) (horn fly), Musca domestica L. (house fly), Musca autumnalis DeGeer ( face fly), and Stomoxys calcitrans (L.) (stable fly) in North America are r eviewed. The species Trichomalopsis americana (Gahan), Trichomalopsis dubia (Ashmead), Trichomalopsis sarcophagae (Gahan), Trichomalopsis tachinae (Ga han), and Trichomalopsis viridescens (Walsh) are described, keyed, and diff erentiated from other recognized North American species. Lectotypes are des ignated for T. dubia, T. sarcophagae, and T. tachinae. Distribution and hos t associations are recorded for the species. Trichomalopsis americana and T . viridescens are newly recorded as parasitoids of M. domestica; T. dubia a nd T. sarcophagae are also newly recorded as parasitoids of Hypoderma linea tum (Villers) (common cattle grub) and Hypoderma bovis (L.) (northern cattl e grub), respectively. Some previously published host associations and para sitoid identifications are corrected based on examination of voucher specim ens. The known biology of each species is reviewed. The presence of Trichom alopsis albipilosa (Gahan) in North America is considered to be erroneous b ased on a misidentification of T. americana.