Usia notata Loew, 1873

Gibbs, David, 2014, A world revision of the bee fly tribe Usiini (Diptera, Bombyliidae) Part 2: Usia sensu stricto, Zootaxa 3799 (1), pp. 1-85 : 76-77

Usia notata Loew, 1873

( Figure 15 , Plate XXI)

Usia notata Loew, 1873: 201 .

Type material examined. LECTOTYPE here designated; Uzbekistan, Кизилъкумъ [= Kizil Kum]/ 9692/ Usia notata Lw / Coll. H. Loew/ Type / Zool. Mus. Berlin [♀ ZMHB] ; PARALECTOTYPE; Kazakhstan, Узуната [= Uzunata]/ Coll. H. Loew/ Typus / Zool. Mus. Berlin [♀ ZMHB].

Originally described from an unspecified number of specimens. Two syntypes were found in ZMHB, both females, the specimen in best condition being selected as lectotype.

Other material examined. Turkmenistan, Bairam-Ali, 28 April 1934, leg. N. Shibanov [♀] ( ZMUM).

Etymology. from Latin notatus, meaning “marking”, probably referring to the brown spot in the middle of the wings.

Diagnosis. A small to medium-sized Usia of central Asia. Mostly black with a faint greenish hue, immediately distinguished from all known species by the yellow anterior half of the frons, sharply demarcated from the shining black hind half. Occiput mostly shining, frons remarkably short and relatively wide, proboscis much shorter than other species, third antennal long. Mesonotal vestiture short, white, marginal scutellar hairs less than half midlength of scutellum. Knees narrowly but distinctly yellow, tergites all dark, sternites all pale. Wings clear but for a brownish infuscation over middle of first basal cell.

Redescription. Measurements. Body length. 2.4–5.0mm. Wing length. 2.2–5.5mm.

Male. Material not seen, but Paramonov (1950) stated “males extremely similar to females”.

Female. Head. Noticeably small and short, frons barely longer than width at antennae. Mouth-margin strikingly broad, clearly visible from directly above, convex, about as broad as length of pedicel; shining, undusted. Anterior half of frons clear yellow, the frons laterally with silvery dust spots leaving central thirds shining undusted. The yellow front of the frons sharply demarcated from the shining black hind half, ocellar tubercle and occiput, latter only dusted on occipital “cushions”. Frons narrowest level with hind corners of eyes, broadening anteriorly, lateral ocellus separated from eye margin by about the diameter of that ocellus. Vestiture very short, on ocellar area no longer than distance between lateral ocelli; on black part of frons a group of short, forwardly curved white hairs occupy lateral quarters. Antennae relatively long, scape brown about a little longer than wide, pedicel blackish, brown ventrally, quadrate, third segment black, very narrowly brownish as base, elongate, narrow, longer than width of frons. Proboscis black, hairless, shorter than most species of Usia , about 1.5–2.0 times the length of the head; palps short, dark brown, clearly clavate with pale hairs, the longest almost as long as the palps. Thorax. Broad relative to head (as in U. lata Loew ), mesonotum and scutellum shining black except for light dusting narrowly on notopleuron and above wing base. Surface conspicuously punctate, although punctures small and simple, separated by their diameter or a little more, with a tendency towards transverse wrinkles in hind part, scutellum decidedly transversely wrinkled. Bare paramedian lines inconspicuous, apparent only on anterior slope of mesonotum. Pleurae predominantly black with a dense covering of grey dust largely obscuring the ground colour; area around anterior spiracle yellow, hind half of anepimeron dull brown to yellow below dust. Mesonotum and scutellum covered with short, arcuate pale yellowish or white hairs, those on disc orientated towards head, those laterally a little longer and orientated towards disc of mesonotum, scutellar hairing similar. Anepisternum and pronotum with hairing similar to that on notopleuron, covering whole sclerite. Wing. Wing membrane clear, only faintly yellow tinged but for a distinct, diffuse brown spot in the first basal cell above the base of the discal cell, spreading to the fork of veins R2+3 and R4+5. Veins yellow basally, beyond R2+3–R4+5 fork R and M veins plus r-m are darker and browner. Anal lobe as broad as anal cell, margin convex; r-m just before the middle of the discal cell. Haltere. Yellow, becoming slightly infuscated at base of stem. Legs. Predominantly shining black, tips of femora and bases of tibia narrowly yellow-brown. Coxae grey dusted and haired as on anepisternum; femora with relatively long, pale hairs, the longest as long as the depth of the femora medially. Tibia and tarsi with a covering of minute pale setulae, a little longer and more erect on tibia, especially basally. Abdomen. Shining aeneous black, the disc of the tergites covered with very short, pale yellow hairs, appearing naked at low power. Laterally and on the down-curved margins the tergites are clothed with rather longer, whitish yellow hairs. Sternites mostly pale yellow with inconspicuous short pale hairs, last visible sternite darker brownish. Genitalia. Furca pigmented, apical part rather robustly constructed, arms long and strongly curved; apical sternite wider than long, brownish, darker than foregoing sternites.

Discussion. A very distinct species with no obvious affinities with any other known species. The very short head and proboscis, long third antennal segment, very broad oral margin and pattern of yellow on head are not found in any other species. The female genitalia also do not suggest any close relationship to other species.

Distribution. Only three specimens seen, one each from Kazakhstan, Turkmenistan, Uzbekistan. Records from Tajikistan are likely to be correct. The area is certainly very under-recorded, but even so the scarcity of specimens suggests that it is far from being a common species.

Figures

FIGURE 15. ♀ U. notata frons dorsal.