The male genital tract of Axymyiidae and Tanyderidae (Diptera)

The male genital tract of Axymyiidae and Tanyderidae, represented by Axymyia furcata McAtee and Protoplasa fitchii Osten Sacken, respectively, are described and illustrated for the first time. The tract of A. furcata is foreshortened, with relatively short, thick vasa deferentia that meet medially at the ejaculatory duct, which empties dorsal to the ejaculatory apodeme. The accessory glands are large and either firmly appressed or fused medially. The tract of P. fitchii has elongate vasa deferentia that curve ventrally and enter the ejaculatory duct separately. The short accessory glands are separate but their exit is uncertain. Neither of these male genital tracts shed further light on the phylogenetic position of these families within the nematocerous Diptera, although Tanyderidae do lack the synapomorphic multi-chambered accessory glands grouping Ptychopteridae + Culicomorpha + Bibionomorpha.