Microdon (Syrphipogon), Hull

Reemer, Menno & Stahls, Gunilla, 2013, Generic revision and species classification of the Microdontinae (Diptera, Syrphidae), ZooKeys 288, pp. 1-213 : 46-47

Subgenus Syrphipogon Hull Figs 221-222

Syrphipogon Hull, 1937b: 120. Type species: Syrphipogon fucatissimus Hull, 1937: 120, by original designation.

Description.

Body length: 25-28 mm. Very large flies with oval abdomen and long, colourful pilosity. Mimics of orchid bees of the genus Eulaema ( Euglossidae ). Head about as wide as thorax. Face more or less straight in profile; narrower than an eye; on ventral half with very long, thick and dense pile, resembling a beard ( ‘mystax’). Eye margins in male converging at level of frons, with mutual distance about twice as large as width of antennal fossa. Antennal fossa about as wide as high. Antenna longer than distance between antennal fossa and anterior oral margin; basoflagellomere shorter than scape, oval, about four times as long as wide, bare. Postpronotum bare. Scutellum trapezoid; with very large, cone-shaped calcars. Anepisternum sulcate; pilose anterodorsally and posteriorly, widely bare medially. Anepimeron entirely pilose. Katepimeron convex; smooth; bare. Wing: vein R4+5 with posterior appendix; vein M1 straight, perpendicular to vein R4+5; postero-apical corner of cell r4+5 widely rounded, without appendix; crossvein r-m located around basal 2/7 of cell dm. Abdomen oval, about 1.3 times as long as wide. Tergites 3 and 4 fused. Sternite 1 pilose. Male genitalia: phallus furcate, with furcation point near base, both processes about equally long, curved dorsad, projecting well beyond apex of hypandrium; epandrium without ventrolateral ridge; surstylus shallowly furcate, with two short and wide lobes.

Diagnosis.

Body length more than 20 mm. Face with very long, thick and dense pile, resembling a beard ( ‘mystax’).

Discussion.

Hull (1937b) erected Syrphipogon , and considered it related to Microdon . Steyskal (1953) referred to Hull’s description in his own description of an apparently very similar species ( Microdon gaigei Steyskal, 1953), but he considered the differences with Microdon insufficient for generic status. In external characters and male genitalia Microdon and Syrphipogon are quite similar. For that reason, Syrphipogon is here still treated as a subgenus of Microdon .

The differences between the two species of Syrphipogon are not very convincing when comparing the description of Steyskal (1953), based on a female, with the holotype of Syrphipogon fucatissimus Hull, 1937, a male. The differences as noted by Steyskal (1953) may be due to sexual dimorphism, but in order to establish this, the type of Microdon gaigei needs to be examined.

Diversity and distribution.

Described species: 2. Neotropical. Only two specimens are known: one from Panama and one from "South America".