Delia bisciliata ( Emden, 1941 )

Ackland, D. M., 2008, Revision of Afrotropical Delia Robineau-Desvoidy, 1830 (Diptera: Anthomyiidae), with descriptions of six new species, African Invertebrates 49 (1), pp. 1-75 : 58-62

Delia bisciliata ( Emden, 1941)

Figs 100 , 103–108

Hylemyia bisciliata Emden 1941 b: 266 ; 1951: 358.

Delia bisciliata (Emden) : Pont & Ackland 1980: 716.

Diagnosis:

♂ Peristomal margin projecting beyond level of insertion of vibrissal setae; genal setae uniserial; prealar seta about 0.5 times as long as posterior npl; fore tibia with short blunt pv apical spur; hind tibia with full row of 10–12 av, 6 ad, 3–4 pd and about 12 pv which are partly biserial.

Description:

Male.

Colour: Frontal stripe, parafrontalia, genae and face black in ground colour, with dark grey dusting which shifts according to angle of vision; head viewed from above with matt velvety black frontal stripe contrasting with golden brassy to whitish parafacials, from in front frontal stripe is light grey dusted with parafacials adjacent antennae darker than genae; genae with shifting areas of lighter and darker patches of dusting; occiput dark grey, blackish above. Antennae black with lighter grey dusting; arista black. Palpi black; prementum of proboscis black with thin grey dust. Thorax black in ground colour, with shifting areas of dark brownish grey dust and shining patches; scutum viewed from above with lighter grey vittae mainly visible presuturally; humeri lighter grey dusted; scutellum concolorous with thorax. Wing membrane brownish tinged; veins brown; squamae slightly paler than wing base, with light brown margin and paler fringe. Halteres pale brown. Legs black. Abdomen black in ground colour, laterally dusted when viewed from behind, with wide black median vitta which covers median third of width of abdomen and consists of triangular marks on each tergite with base along anterior margins of tergites. Prehypopygial tergites thinly grey dusted.

Head: Eyes separated posteriorly (by at least twice diameter of anterior ocellus), frontal stripe distinct throughout; parafrontals linear; parafacials medially equal to width of postpedicel; peristomal margin slightly projecting in lateral view, slightly in front of profrons, and projecting beyond level of vibrissae; gena below lowest point of eye margin 0.33–0.35× eye height; face concave, distance between vibrissal setae slightly more than (1.3×) distance between them and nearest eye margin. Four pairs of parafrontal setae on anterior half of frons; 1 pair of rather strong interfrontal setulae, half way between upper frontal setae and anterior ocellus; genal setae uniserial anteriorly. Postpedicel twice as long as wide, not reaching peristomal margin (by almost its width); arista very short pubescent, longest hairs hardly as long as basal aristal diameter. Proboscis short, with prementum as long as palpi and slightly wider than fore tibia. Upper occipital setulae with a few setulae below row.

Thorax: 1 pair of presutural acr longer, differentiated from accessory setulae, acr: dc ratio 10:5:10, no hairs between rows; 2 posthumeral setae; notopleural depression bare apart from two strong setae; prealar about half length of posterior npl, but finer, placed midway between suture and supra-alar seta; scutellum bare on disc centrally and basally; anepisternite without developed upper anterior setula; katepisternals 1+2, lower posterior 2/3 as long as upper.

Wing: Vein C with anterior spinules short but not weak, as long as or slightly longer than diameter of C, stronger spines before distal break nearly as long as small crossvein; lower surface of C bare. Large crossvein very slightly sinuate, last section of M 1+2 1.30–1.35× length of preceding section; lower squama smaller in area than upper. Wing length 3.5–4 mm.

Legs: Mid femur with 3–4 av in proximal half, rest of av very short and not erect, 3–4 pv; hind femur with 3–5 av in distal half (not longer than depth of femur), about 3–4 preapical pv; fore tibia with a short fine blunt apical pv, 1 median pv; mid tibia normally without an av, but lectotype has a small rather distal av on left tibia only, 2 ad, 2 pd, 2 pv; mid tarsomere 1 without lengthened dorsal setulae, hind tibia with full row of 10– 12 av, 6–8 ad, 3–5 pd (distal one longest), and about 12 pv on most of length, these being partly biserial; some extra setae also between av and ad setae.

Abdomen: About 2.3 times as long as greatest width (at basal margin of sternite III dorsoventrally compressed; sternite III ( Fig. 105 ) nearly as wide as sternite IV; sternite IV ( Fig. 105 ) more or less quadrilateral, with curving lateral margins.Sternite V processes ( Fig. 105 ) 1.75× length of base, with a few short fine setulose hairs on inner margins, lateral setae numerous (about 26–30), of more or less equal length (as long as processes). Surstyli 1.1–1.2× length of cercal plate, in caudal view ( Fig. 103 ) becoming narrower with pointed apices, outer margins clothed with fine hairs, in lateral view ( Fig. 104 ) straight or slightly downcurved. Cercal plate twice as wide as long, apex narrowly rounded, apical setae short. Pregonite ( Fig. 108 ) with 1 seta; postgonite triangular without setae. Aedeagus with distal section ( Figs 106, 107 ) rather short, 1.2 times as long as aedeagal apodeme, divided in distal 2/3 into pair of free paraphallic processes, dorsal prolongation as long as paraphalli.Aedeagal apodeme rod-like, in dorsal view about 8– 9 times as long as width. Ejaculatory apodeme 0.16–0.17 times as long as aedeagal apodeme.

Female.

Colour: Head dark in ground colour with shifting dark grey to bronzy dust; frontal stripe black, sometimes dark brown anteriorly, viewed from above matt black, from in front becoming increasingly light brown and then contrasting with deep matt black parafrontals; parafacials deep golden dusted when viewed from in front; frontal triangle bronzy dusted with black spot in front of anterior ocellus; genae greyish dusted with darker shifting patch (when viewed laterally), leaving narrow lighter strip level with lower margin of eye; occiput with darker and lighter shifting brown dust; prementum brown, semi-shining; palpi brown. Thorax black in ground colour with shifting lighter brown dust and darker semi-shining patches; scutum when viewed from above with wide lateral chocolate brown vittae and indistinct median and paramedian vittae, humeri and notopleural area light grey dusted. Wing membrane tinged brownish, veins brown. Legs blackish brown, semi-shining. Abdomen black in ground colour, viewed from above somewhat shining, viewed from a lower angle from behind with wide brown median vitta and darker lateral and anterior patches on each tergite, median vitta bordered with grey dust.

Head: Eyes widely separated (by 1.3–1.4× their transverse width); frontal stripe at level of middle orbitals twice as wide as each parafrontal; parafrontalia widening anteriorly to about 1.5× width of postpedicel. Parafrontal setae differentiated into 3 pairs of orbitals (all more or less lateroclinate), and 2 pairs of inclinate frontals; postpedicel not quite twice as long as wide, not reaching peristomal margin; crossed interfrontal setae placed at apex of frontal triangle; gena below lowest point of eye margin 0.4× eye height; 1 pair of strong vibrissal setae, with short supravibrissal setula, 2 subvibrissals, 2 upcurved uniserial genals, 3–4 postgenal setae. Prementum as long as palpi.

Thorax: acr very short and fine (not differentiated from accessory setulae and hairs), 1 pair of longer presutural acr (about half length of 1st presutural dorsoventrals), biserial, no hairs between rows; acr: dc ratio 10:7:10; 1+1 posthumerals. Notopleural depression bare, apart from 2 strong setae. Prealar seta about half length of posterior npl but finer; scutellum almost bare on disk; anepisternite without developed upper anterior setula; 2 proepisternal setae (one short), 1 proepimeral seta, katepisternals 1+1.

Wing: Vein C with marginal spinules only slightly longer than vein diameter, stronger pair before distal break equal to length of small crossvein; large crossvein straight, last section of M 1+2 is 1.3× length of preceding section.Vein C bare ventrally. Lower squama not projecting, smaller in area than upper. Wing length 4.0 mm.

Legs: Mid femur with 1 av in proximal half, a few short pv; hind femur with 4–5 av in distal half; fore tibia with 1 ad, 1 pv at same level; mid tibia without av, 2 ad, 2 pd, 2 pv; hind tibia with 4–5 av, 3–4 ad, 3–4 pd, no pv.

Abdomen:About as long as thorax, tergites with only short hindmarginal setae (including tergite V without long discals). Postabdomen when fully extended as long as preabdomen; very similar to D. bracata , only differing as follows: sclerites of sternite X ( Fig. 100 ) each bearing 3 or 4 setulae on posterior margin; sternite X wider; cerci slightly shorter and more widely set apart.

Lectotype ♂: ‘LECTOTYPE’ [circular printed white label with purple border]; ‘ KENYA: / Aberdare Range. / x.1935 / B. M. E. Afr. / B. M. 1935–203’ [white printed rectangular label]; ‘ Nyeri Track. / 10500 ft / F.W. Edwards’ [white printed rectangular label]; ‘ Hylemyia / bisciliata sp. n. / van Emden det. 1940’ [white printed and written rectangular label]; ‘type’ [red handwritten rectangular label] (BMNH). Lectotype in good condition with all legs and wings intact. There is a label in the drawer next to the lectotype ‘ Lectotype fixed by Emden, 1951:361’.

Paralectotypes (all BMNH): KENYA: 34 ♂ 15♀Aberdare Range, 28.x.1934, B.M.E. Afr. Exp. B.M. 1935– 203, Nyeri Track, alt. 10500 ft, J. Ford; 4 ♂ 2♀Mt Kinangop, alt. 10000 ft, 26.x.1934, F.W. Edwards . UGANDA: 1 ♂ Imatong Mts, alt. 10800 ft, ii.1936, D. R. Buxton; 1 ♂ Kigezi Dist., Mt Muhavura , alt. 7000 ft, 29.ix.1934, F.W. Edwards .

Other material examined (all BMNH): KENYA: 1 ♂ Mt Kenya, Kathita R., alt. 9900 ft, 9.viii.1949, J.A. Riley; 1 ♂ 3♀Mt Kenya, N side, heather, stream, alt. 11000–12000 ft, 20–22.xii.1980, P.S. Cranston; 1 ♂ Embu, 20.ii.1914 .

Discussion: There is an additional male (not described here) in the BMNH which may be this species, caught together on Mt Kenya with 1 ♂ and 3♀by P. Cranston (data listed above), which has slightly different genitalia. These differ from D. bisciliata as follows: cercal plate slightly shorter and wider, with a more rounded apex; surstylus in caudal view slightly wider, in lateral view with the apex not upturned; processes of sternite V slightly longer; distal section of aedeagus with paraphalli slightly longer. Further material may show that these small differences are constant.

Life history: Unknown.

Distribution: The original material on which Emden based this species in 1941 was from Kenya and Uganda. Very few further specimens have been found since then, all of them on Mt Kenya, the most recent being collected in 1980.

Figures

Figs 99–102. Delia spp., female abdomen, terminal segments, ventral view: (99) D. andersoni (Kenya); (100) D. bisciliata (Kenya); (101) D. metatarsata (Kenya); (102) D. cameroonica sp. n. (Cameroon). Scale bar = 0.1 mm.

Figs 103–108. Delia bisciliata, male paratype (Kenya): (103) cercal plate and surstyli; (104) ditto, lateral view; (105) sternites III–V; (106) basiphallus and distiphallus, lateral view; (107) distiphallus, ventral view; (108) gonites. Scale bar = 0.1 mm.