sexfasciatus group Diagnosis Katepisternum with a posterodorsal and a small posteroventral pile patch, with or without a few short setae below the dorsal patch. The bare, flat posterior margin of tergite 1 (almost) entirely without microtrichia. Base of wing entirely microtrichiose or at most with small bare areas in cells br, bm, or cup. Anepisternal setae saw-like. Tarsomere 1 of protarsus anterodorsally without black spinules between the yellow setae. ♂: Sternite 4 with inflated caudal lobes, partly without microtrichia, and with a small accessory lobe close to the base of the lobes. Genital pouch large, more than half as wide as abdominal segment 4 at anterior margin. Posterior surstyle lobe (Fig. 13E:y, F:y) straight, without hook, directed medially. Median surstyle lobe (Fig. 13E, F:w) setose along posterior half of ventral margin, on median surface without accessory lobe, without microtrichia, its posterior end extended, forming a wide rounded lobe directed posteromedially. Cerci (Fig. 10L:z) with pointed apex, with sclerotized and setose ventral surface. Subepandrial sclerite strongly curved, its anterior part almost parallel to the posterior part, a complete sclerotized bridge at its anterior end, the posterior part microtrichiose on full length, without a bulging ‘pad’ (Fig. 13G:z). Hypandrium (Figs 11L, 12K) with a very wide base and lateral ‘shoulders’ between the wide proximal and the narrower distal part, apex slightly produced beyond ctenidium and blunt. Ejaculatory apodeme large. ♀: tergite 5 and sternite 5 with posteriorly directed setae, ovipositor with moderately thick setae, without tooth. Included species Megatrigon flavimarginatus (Hull, 1964) comb. nov. (Eumerus; holotype in BMNH, examined). Megatrigon jacobi (Hervé-Bazin, 1913) comb. nov. (Eumerus; holotype in MRAC, examined). = Eumerus connexus Hull, 1964, syn. nov. (holotype in BMNH, examined). Megatrigon sexfasciatus Johnson, 1898 (holotype in BMNH, examined). Due to the lack of sufficient material, the species of the sexfasciatus group are not (re)described in the present account. Megatrigon jacobi comb. nov. (Figs 1L, 2M, 3L, 7L, 13E) is a distinctive species readily recognised by the reduced mouthparts and related features of the lower parts of the head (similar to Merodon bombiformis Hull, 1944). The identity of M. sexfasciatus remains obscure. The material that has been available for the present study consists of males of several species that in external characters are very similar to the female holotype of M. sexfasciatus. At present we cannot assign any of the available males to the nominal taxon M. sexfasciatus. There are several ‘morphs’ similar to the type of M. flavimarginatus comb. nov. in the available material. However, as most of these are represented by singletons, we are unable to assess the significance of the observed, often slight, morphological differences and for that reason we refrain from describing them here. More material in good condition is needed to uncover the species diversity in the sexfasciatus group, but we expect that a good number of distinct species will be discovered.

Published as part of Doczkal, Dieter, Radenković, Snežana, Lyneborg, Leif & Pape, Thomas, 2016, Taxonomic revision of the Afrotropical genus Megatrigon Johnson, 1898 (Diptera: Syrphidae), pp. 1-36 in European Journal of Taxonomy 238 on page 29, DOI: 10.5852/ejt.2016.238, http://zenodo.org/record/3849874