Xenomyia osculata, Pont & Werner, 2003

Xenomyia osculata View in CoL sp. n.

( Figs 1–11 View Figs 1–2 View Figs 3–5 View Figs 6–8 View Figs 9–10 View Fig )

Holotype ♂: SOUTH AFRICA: Northern Cape: Gifkloof, 15 km E of Upington, 28.26.05 S, 21.23.45 E, 11.xi.1996, R.W.Palmer. In NMSA. GoogleMaps

Paratypes: Same locality data (5♂ 2♀ NMSA, 2♂ 1♀ BMNH, 2♂ ZMHU).

Etymology: The epithet osculata is formed from the Latin verb ‘osculari’, ‘to kiss’, and refers to the kiss of death administered by Xenomyia to its prey.

Male:

Head: Of extraordinary shape ( Figs 1 View Figs 1–2 , 3 View Figs 3–5 ), the eye small, the frons arched; the frontoorbital plates enlarged and touching for almost their entire length, completely devoid of setae but mostly covered with dense small setulae. Ground-colour black. Frons broad, the margins concave ( Fig. 1 View Figs 1–2 ), at mid-length 0.33 of greatest head-width. Eye with a few short sparse hairs, without areas of enlarged facets. Ocellar setae absent. Inner verticals strong, convergent; outer verticals short, one quarter length of inner verticals, hardly twice as long as the adjacent post-ocular setulae. Fronto-orbital plate, parafacial and vibrissal area brown pruinose, from some angles the fronto-orbital plate more goldenbrown and with traces of a weak silvery spot just before lunula (stippled in Fig. 1 View Figs 1–2 , arrow in Fig. 3 View Figs 3–5 ); upper third of occiput grey pruinose, lower occiput, gena and face white. Fronto-orbital plates enlarged and arched, with dense short setulae for their entire length and for most of their width; without trace of frontal or orbital setae; frontal vitta completely suppressed. Parafacial at middle 0.4 width of antennal flagellomere, bare. Antennomeres and arista black.Antenna almost reaching mouth-margin; in lateral view, flagellomere twice as long as broad. Arista very short, only slightly longer than length of flagellomere; short-pubescent, the longest individual hairs as long as basal width of arista. Vibrissae strong, with a strong pair of subvibrissals, the vibrissal setulae ascending to mid-length of facial ridge. Gena deep, 0.3 of greatest eye-depth; genal row of setae sparse and weak. Proboscis elongate ( Fig. 3 View Figs 3–5 ), dark brown, prementum undusted, glossy; labellum with 3 pairs of stout teeth. Palpi rather swollen in apical third, yellow, becoming brown on the swollen part.

Thorax: Ground-colour black. Scutum dark brown, subshining, with a median presutural patch of white dust between the dorsocentrals that extends backwards to level of first postsutural dorsocentral or just beyond and which is medially completely or partly divided by the dark ground-colour; usually with pair of indistinct small grey patches between the dorsocentrals in front of scutellum; the area between presutural intra-alar, presutural supra-alar and postpronotal setae, and the entire notopleuron, white dusted; pleura white to light grey dusted, tinged with brownish on upper and posterior anepisternum and anterior katepisternum. Scutellum dark brown, subshining, the margins grey dusted. Scutal ground-setulae short and sparse. Acrostichal setulae in 2–3 rows before suture, 3–4 irregular rows behind suture, the prescutellar setae hardly distinct. Dorsocentrals 2+3. Intra-alars 1+2. Supra-alars 1+1, prealar absent. 1 postpronotal (the outer), the lobe covered with short dense setulae. Prosternum bare. Proepisternal depression bare; 1 seta and 1–2 adjacent setulae. 1 proepimeral, with a forwardly-directed setula below. Notopleuron with 2 setae, the posterior one half as long as anteror one, without setulae. Anepisternum without a short seta in upper anterior corner. Katepisternals 1+2, only the upper posterior one strong, the lower posterior one much closer to upper posterior than to anterior seta. Anepimeron, katepimeron, meron, katatergite and anatergite bare. Posterior spiracle without setae on margins. Scutellum with a pair of sub-basal lateral and apical setae; disc sparsely setulose, lateral margins and ventral surface bare.

Legs: Legs apparently wholly dark brown, but because the specimens have been retrieved from alcohol some of them have the femora and tibiae partly yellow, but this appears to be an artefact. Fore coxa with several spine-like setae and setulae on anterodorsal surface. Fore femur without anteroventral setae; with a posterodorsal row and several posterior setae around middle; a row of 5–7 short spine-like posteroventral setae ( Fig. 4 View Figs 3–5 ). Fore tibia without submedian setae; dorsal and posteroventral apical setae very short, less than tibial diameter. Mid femur without ventral setae, with 1–2 short anterior setae around middle; 0 anterior and 1 posterior preapical seta. Mid tibia with 1 submedian posterior seta, otherwise without setae. Hind femur with an anterodorsal row and 1 posterodorsal preapical seta; without ventral setae. Hind tibia with only 1 anterodorsal and 1 posterodorsal seta at middle, both at about the same level; 1 short dorsal apical, without anterodorsal or posteroventral apicals. All tarsi long, slender, without modifications, the claws not elongated.

Wing ( Fig. 5 View Figs 3–5 ): Wing membrane completely covered with microtrichiae, but in apical half of wing with an area of longer denser microtrichiae between vein R 4+5 and costa ( Fig. 5 View Figs 3–5 ), resembling a wing-cloud. Basicosta and tegula black. Venation as in Fig. 5 View Figs 3–5 , veins bare except for costa. Calypters creamy-white, lower one of the ‘ Phaonia -type’ and projecting slightly beyond upper one. Haltere with the stalk creamy and the knob white.

Abdomen: Ground-colour black. Tergites subshining brownish-black, with narrow areas of grey dust appearing like inverted triangles along the sides of tergites 1+2, 3, 4 and 5. Tergites with few setae, tergites 3, 4 and 5 each with 2–3 pairs of fine lateral marginals. Sternite 1 bare, sternites 2–4 grey dusted and with a few sparse setae; sternite 5 as in Fig. 6 View Figs 6–8 .

Genitalia ( Figs 7–10 View Figs 6–8 View Figs 9–10 ): Cercal plate divided. Surstyli short, stout. Aedeagus with the epiphallus well-developed; phallapodeme narrow; praegonite (gonopod) long, simple; postgonite (paramere) with a micro-haired, membraneous area in apical part; distiphallus simple, juxta without spinules.

Measurements: Wing length 3.5–4.0 mm. Body length 4.5–5.0 mm.

Female:

Differs from the male as follows:

Head: Shape and structure very different from the male. Frons broad ( Fig. 2 View Figs 1–2 ), at midlength 0.42 of greatest head-width, more or less parallel-sided. Eyes bare. Ocellars absent. Outer verticals stronger, half length of inner verticals. Fronto-orbital plates dull grey pruinose, conspicuously tinged with brown in upper half, white below against eye-margin; parafacial, face, gena, lower half of occiput white, upper half of occiput grey, vibrissal area narrowly brownish. Fronto-orbital plates broad, at mid-length 0.6 width of frontal vitta and 0.27 width of frons. 3–4 pairs of frontal setae, directed inwards and forwards; 1 pair of orbitals, also directed inwards and forwards; the plates otherwise covered with short fine dark setulae, but these longer and sparser than in male. Frontal vitta bare; frontal triangle narrow and reaching to lunula. Parafacial slightly broader. Antennal flagellomere narrower but still twice as long as broad. Arista longer and narrower, 1.4 times length of flagellomere; the longest hairs thus slightly longer than its basal width.

Thorax: Pleura mostly white dusted, the darkening only weakly indicated.

Legs: Fore femur on posteroventral surface with 3–4 long fine setae, without spine-like setae.

Wing: Faintly smoky, but without the area of longer denser microtrichiae.

Abdomen: Setae weaker and less differentiated.

Ovipositor ( Fig. 11 View Fig ): Twice as long as length of tergite 5. Tergites 6, 7 and 8 welldeveloped, broadly divided dorsally. Cerci not separated from epiproct, these two setulose and without spines. Sternite 6 elongate-rectangular; sternite 7 represented by a very small plate; sternite 8 absent, or at least not detected. The membrane between sternites 7 and 8 microspinulose. Hypoproct elongate-semicircular, setulose and without spines. 3 spherical spermathecae.

Measurements: Wing length 4.5–5.0 mm. Body length 5.5–6.0 mm.

Distribution: Known only from the middle Orange River, Northern Cape, South Africa.