Microdon (Megodon) stuckenbergi (Keiser)

Reemer, Menno & Bot, Sander, 2015, Six new species of Microdon Meigen from Madagascar (Diptera: Syrphidae), Zootaxa 4034 (1), pp. 127-147 : 145-146

Microdon (Megodon) stuckenbergi (Keiser)

( Figs 56–61 )

Megodon stuckenbergi Keiser, 1971: 253

Diagnosis. One of the two known species of the subgenus Megodon , which differs from other species of Microdon in the occiput, which is narrow and evenly wide over its entire length, and also by the wide and deep longitudinal groove in the male hind basitarsomere. Microdon stuckenbergi differs from M. planitarsus by its larger size (12 mm) and the much larger scutellar calcars ( Fig. 60 ).

Type material studied. HOLOTYPE. Male. Label 1 (red): " Typus "; label 2: " Megodon stuckenbergi Keiser "; label 3: " Madagascar Nord, Montagne d'Ambre 1700 m, det. Diégo-Suarez, 11-15.XII.58. B. Stuckenberg"; label 4: "Muséum Paris, Megodon stuckenbergi Keiser 1971 ". Coll. MNHN.

Redescription of male holotype. Body size: 12 mm. Head. Face dark brown laterally, pale brown medially, yellowish dorsally; yellow pilose, except bare medially and dorsally. Gena dark brown, yellow pilose. Oral margin laterally slightly produced. Frons and vertex brown; yellow pilose. Occiput narrow over entire length; blackish; white pilose; white pollinose. Eye bare. Antennal fossa slightly higher than wide. Antenna yellowish brown, basoflagellomere darker near apex; antennal ratio approximately as 3.5:1:2.5. Arista brown, slightly longer than basoflagellomere. Thorax. Mesoscutum dark brown, yellowish white pilose. Postpronotum pale brown; pale pilose. Postalar callus pale brown; pale pilose dorsally, black pilose ventrally. Scutellum pale brown; making angle of about 30° with mesoscutum in lateral view; posteriorly with a pair of large, conical calcars, of about 2/3 of length of scutellum; yellow pilose dorsally, black pilose ventrally. Pleurae brown. Anepisternum with shallow sulcus separating anterior from posterior part; anterior part yellow pilose, posterior part black pilose, with widely bare part in between. Anepimeron entirely black pilose. Katepisternum whitish pilose dorsally; bare ventrally. Katatergum long black microtrichose, anatergum short microtrichose. Calypter greyish white. Halter yellow. Wing. blackish infuscated; entirely microtrichose, except bare on basomedian part of alula (only margins microtrichose). Legs. Brown, with femora a shade darker than tibiae and tarsi; femora and tibiae black pilose anteriorly and dorsally, pale pilose posteriorly; tarsi black pilose dorsally and ventrally, except hind tarsus yellow pilose ventrally. Coxae and trochanters brown; pale pilose. Abdomen. Tergites brown, with faintly demarkated pairs of large yellowish brown maculae on tergites 2 and 3, leaving a narrow dark median line, narrow dark posterior margins and wide dark lateral margins. Tergite 4 largely brown, with faint yellowish brown maculae at anterior margin. Pilosity of tergites mixed white and black. Sternite 1 dark brown; bare. Other sternites yellow; white pilose, except sternite 4 black pilose. Genitalia as in Fig. 61 .

Female. Unknown.

Figures

FIGURES 56 – 61. Microdon (Megodon) stuckenbergi (Keiser). Male holotype. 56. Habitus dorsal. 57. Habitus lateral. 58. Head frontal. 59. Head lateral. 60. Thorax dorsal. 61. Genitalia lateral.