Merodon cuthbertsoni Curran, 1939

Vujic, Ante, Radenkovic, Snezana & Likov, Laura, 2018, Revision of the Palaearctic species of the Merodondesuturinus group (Diptera, Syrphidae), ZooKeys 771, pp. 105-138 : 123-125

Merodon cuthbertsoni Curran, 1939 Figs 13A, C, D, 14

Type material.

Holotype: male, in AMNH. Original label: Zimbabwe, Sanyati Valley S. Rhodesia, 9-10.1925, leg. R. H. R. Stevenson, det. Curran.

Diagnosis.

Face covered with microtrichia; black terga without lateral orange maculae, and terga 3 and 4 each with very narrow microtrichose fascia, approx. 1/10 of tergal length. Morphologically related to the species M. desuturinus from which it can be distinguished by the following features: eye contiguity is approx. 8 facets long (Figure 13A) (the eyes are separated in M. desuturinus , Figure 13B); tarsi entirely pale (dark brown dorsally in M. desuturinus ); male genitalia: posterior surstyle lobe with narrow apex pointed upwards (Figure 14A) (triangular in M. desuturinus , Figure 11A); hypandrium with ventral margin of theca angled and folded (Figure 14C) (rounded and unfolded in M. desuturinus , Figure 11C). M. cuthbertsoni is known only from Zimbabwe (Sanyati Valley in southern Zimbabwe), whereas M. desuturinus is endemic to just a few high Balkan mountains (Europe).

Redescription.

Male.Head (Figure 13A, C): Antenna (Figure 13C) brown, basoflagellomere 1.1 times as long as wide; arista brown and thickened basally and dark brown apically, 1.3 times longer than basoflagellomere, covered with short, dense mi crotrichia. Face and frons black, covered with long whitish yellow pile and sparse silver microtrichia. Oral margin shiny black, slightly protruded. Vertical triangle isosceles (Figure 13A), three times longer than eye contiguity, shiny black except in front of anterior ocellus that has white microtrichia, covered with long whitish yellow pile. Ocellar triangle slightly isosceles. Eye contiguity approx. 8 facets long. Eye pile as long as scape, pale. Occiput with whitish yellow pile, along the eye margin with dense white microtrichia and posteriorly with metallic bluish greenish lustre.

Thorax: Scutum and scutellum black with bronze lustre, covered with dense, erect yellow pile. Pleuron covered with grey-green microtrichia and the following parts with long yellow pile: posterior part of anterior anepisternum, posterior anepisternum (except anteroventral part), anepimeron, metasternum, and anterior, posterodorsal and posteroventral parts of katepisternum; katatergum with short, dense, erect, light-brown pile. Wing hyaline, with dense, brown microtrichia. Calypter pale yellow. Haltere with light brown pedicel and yellow capitulum. Femora dark brown-black, except for usually paler apex; tibiae dark brown with pale basal and apical parts; all tarsi yellow. Metatrochanter without processes. Metafemur (Figure 13D) thickened and slightly curved.

Abdomen: Black with bronze reflections, as long as mesonotum. Terga 2-4 each black with more or less distinct white transverse fascia of microtrichia, interrupted in the middle; pile on terga erect and yellow, except for central parts of terga 2-4 that are covered with adpressed black pile. Sterna blackish brown, covered with long pale yellow pile.

Male genitalia (Figure 14): Posterior surstyle lobe narrow, pointed upwards (Figure 14A); ventral margin of surstylus convex (Figure 14A); anterior surstyle lobe bent inwards (Figure 14B); median part of surstylus with one inner thorn (Figure 14B); cercus elongated (Figure 14A). Hypandrium with folded thecal ridge (Figure 14C: vr) and angular ventral margin (Figure 14C). Lateral sclerite of aedeagus narrow, gradually tapering, with the tip curved downwards (Figure 14C).

Female. Unknown.

Distribution. Species endemic to Zimbabwe.