Oxysarcodexia xon (Dodge, 1968)

(Figs 287–289)

Xarcophaga xon Dodge, 1968: 449; Panama, Canal Zone, Barro Colorado Island. Holotype male in UKAL (examined from photographs).

Diagnosis. [Based on the original description (Dodge 1968), on the diagnosis given by Lopes (1975c), and on photographs provided by courtesy of Dr. Michael Engel and Dr. Caroline Chaboo (UKAL).] Male. Length 5.0–6.0 mm. Postocular plate with pale golden pollinosity. Ocellar bristles weakly developed. Thorax and abdomen with silvery pollinosity, although T5 presents yellowish pollinosity, more evident laterally. Three well-differentiated post-sutural dorsocentral bristles. Apical scutellar bristles absent. T3–4 with 1 pair of median marginal bristles. ST5 with deep median V-shaped cleft and short prolongations. Cercus straight (lateral view), with expanded obliquely cut apex. Cercus with bristles ventrally over full length. Pregonite with expanded base and gradual narrowing at apex; unicolorous. Postgonite with expanded base and sudden narrowing at apex; unicolorous. Distiphallus with serrated margin, lateral expansions, rounded apex and slightly sinuous dorsal outline. Vesica symmetrical; distal lobes well developed, with filaments, tapering, membranous, without spines.

Remarks. Lopes (1975c) treated Xarcophaga as a synonym of Oxysarcodexia, but he was undecided whether or not the grouping of species presenting an apical enlargement of the distiphallus, i.e., a distal widening of the juxta, should have status as a valid genus. Dufek & Mulieri (2017) also pointed out that species included in this group share more elongate and narrow male cerci, a more elongate phallus, and juxta folded further backwards posteriorly. See remarks under O. ariozanoi . Female unknown.

Distribution. NEOTROPICAL. Brazil (Rio de Janeiro), Panama.

Biology. Unknown.

Type material examined. No specimens were examined directly, but photographs of the holotype were provided by courtesy of Dr. Michael Engel and Dr. Caroline Chaboo (UKAL) .