Microdon (Syrphipogon) gaigei Steyskal, 1953.
Steyskal, G.C. (1953) A new melissomimetic fly of the genus Microdon (Diptera, Syrphidae). Occasional Papers of the Museum of Zoology University of Michigan 551, 4 pp.
Microdon (Syrphipogon) gaigei is close to Microdon (Syrphipogon) fucatissimus Hull, but is larger by 3 mm, and differs also in having silvery pilose spots on the facial orbits, a proportionately smaller second antennal segment, a less convex face, wider gena, and a black arista; it has somewhat different banding on the abdomen.
Thompson (pers. comm.) does not agree to include M. gaigei into Syrphipogon as it is very distinct from M. fucatissimus.
Adapted from original description (Steyskal 1953).
FEMALE.
Entire body shining jet-black, except dark brown ultimate tarsal segments, orange-brown margin of last abdominal tergum, and yellowish proboscis and pulvilli. Antennal arista also black.
Head entirely black pilose, except for two small silvery white pilose spots on each facial orbit as indicated; a rather dense beard of stiff, curved pili about anterior oral margin; a shining bare triangular area above antennae, extending a little more than halfway to anterior ocellus. Ocellar triangle small, placed at a distance approximately equal to its length anterior to the posterior orbits; posterior ocelli slightly closer to each other than to anterior ocellus; ocellar region rather tumid.
Thorax with all pilosity black. Scutellum somewhat upturned, its spines and lateral margins with rather long and dense pile. Legs black pilose except plantar brush of tarsi, which is dark brown. Metatibiae compressed, bearing in their distal two-thirds a fringe of black pili almost as long as tibia is wide, and crossed (on anterior face, at least) by a very well-marked suture or groove extending distad at a 45° angle from the middle of the ventral edge. Tarsi broad and strongly depressed, metabasitarsi especially broad. Relative lengths of tarsal segments on mid-line as follows (counting from base): pro- and mesotarsi, 4.5, 2.0, 1.2, 1.3; metatarsi, 9.5, 3.5, 2.0, 1.2, 3.0. Metafemora lacking bristly pili below. Wings: basal half, including alulae and squamae and their fringes, blackish, but the black limited as shown, especially in anterior part; apical half yellowish or almost hyaline, with two light brown spots as shown.
Abdomen broad and convex; last tergum somewhat compressed and with margins overhanging venter. Third and fourth terga with dense, raised crossbands of recumbent pale yellowish gray pile in middle; second tergum with a similar band that is less dense, scarcely raised, and almost interrupted mesad. Posterior margin of fourth and entire fifth terga densely golden-orange pilose. Venter black with black pilosity except for an extensive orange pilose area in middle of fifth sternum.
unless otherwise stated