TAXONOMY AND PRELIMINARY PHYLOGENY OF THE PARASITIC GENUS APOCEPHALUS, SUBGENUS MESOPHORA (DIPTERA, PHORIDAE)

The species of Apocephalus, subgenus Mesophora, are revised and twenty-eight species are recognized, including the following twenty-two new to science: from the Nearctic Region A. brunnipes, A. gemursus, A. pristinus, A. setialvus and A. unitarsus, and from the Neotropical Region A. absentis, A. adustus, A. anfractus, A. angustistylus, A. bisetus, A. brevicercus, A. curtus, A. gracilis, A. hansoni, A. leptotarsus, A. longistylus, A. micrepelis, A. moraviensis, A. prolatus, A. trisetus, A. tritarsus and A. truncaticercus. Additionally, three species known only from female specimens are described but not formally named. A lectotype is designated for A. mortifer Borgmeier, and immature stages of A. borealis, A. antennatus and A. mortifer are described. Unlike larvae of other Apocephalus species, all of which are parasites of ants (Hymenoptera: Formicidae), those of Mesophora species are parasites of various other hosts.