A REVISION OF THE GENERA OF THE SYRPHINI (DIPTERA: SYRPHIDAE)

Abstract A revised generic classification of world Syrphini is proposed. It is based on a study of characters of the adults of 318 described species plus approximately 85 more species as yet either undescribed or unidentified. Thirty-seven genera are recognized; keys to these genera, and to the smaller number of genera known from each of the major zoogeographic regions (except the eastern Palaearctic and Oriental) are presented. Eight new genera, Notosyrphus (South America), Exallandra (Ethiopian Region), Citrogramma (Oriental Region and Australia), Dideomima (Mexico), Hermesomyia (Ecuador), Pseudoscaeva (North and South America), Antillus (Haiti), and Giluwea (New Guinea), and two new subgenera, Melangyna ( Austrosyrphus ) (Australia and New Zealand) and M . ( Melanosyrphus ) (New Guinea), are described. Nine new species, in Melangyna ( Melanosyrphus ), Citrogramma , Hermesomyia , Antillus , and Giluwea , are described. The genus Orphnabaccha is transferred from the tribe Bacchini to the Syrphini, and the genus Toxomerus (including Mesograpta ) is referred to the tribe Toxomerini. Maps showing the world distribution of each genus and subgenus, and figures of the male terminalia of the type-species of almost all genera and subgenera, are presented.The peculiar nature of the Neotropical fauna of Syrphini, with almost all species belonging to two large and very diverse genera, is compared with the situation in the rest of the world, where in most major regions the Syrphini consist mostly of a moderate number of medium-sized genera each of which shows much less diversity. Possible reasons for this difference, and for the great preponderance of more primitive Diptera among those with apparent transantarctic relationships, are suggested.