A new morphological character to distinguish Sergentomyia and Phlebotomus

Although the genera Sergentomyia, Phlebotomus and Lutzomyia are widely accepted, there is no character state which distinguishes them. Many Sergentomyia spp. have erect abdominal tergal setae normally characteristic of Phlebotomus; some Sergentomyia spp. lack cibarial armature "characteristic" of the genus, while some Phlebotomus spp. show this armature. Lutzomyia is "defined" by thoracic pleural setae and a cibarial bulge, both of which states occur on Old World forms. Lutzomyia may be defined geographically, but the use of geographical distribution in taxonomy leads to circular biogeographical arguments, and is invalid. The microtrichia of abdominal tergite six and sometimes four and five of the males of ten species of Sergentomyia (Subgenera Grassomyia, Sintonius, Sergentomyia and Parrotomyia) were found to be dimorphic. Those of 16 species of Phlebotomus, Chinius and Lutzomyia were monomorphic. In the subgenus: Parvidens, S. lesleyae males had dimorphic microtrichia on tergites five and six while those of S. heischi were monomorphic. Two other characters of tergal chaetotaxy, of probable taxonomic potential, are also described.