Delia madagascariensis, Ackland, 2008

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 : 31-34

Delia madagascariensis sp. n.

Figs 31–36

Etymology: The specific name refers to Madagascar where the holotype was collected.

Diagnosis:

♂ Prealar absent, leg setae short and fine, the av, ad and pd on mid tibia hardly longer than diameter of tibia; hind tibia with 2 ad and 2 pd; acr short and fine, hardly differentiated from accessory setulae; large crossvein straight; sternites II and III ( Fig. 33 ) very long and narrow.

Description:

Male.

Colour: Frontal stripe, parafrontals, parafacials, genae and face varying from blackish to orange in ground colour, with pale gold dusting; frontal stripe black when viewed from above or in front but when viewed from in front at a low angle silvery grey dusted; parafacial at level of aristal base with shifting blackish to orange sheen-stripe, which viewed from above is pale gold dusted; occiput dark grey, darker above. Antennae brown, basal segments sometimes obscurely lightened orange. Palpi brown, sometimes paler basally; prementum of proboscis brownish with thin grey dust. Thorax translucent brown in ground colour, with fairly dense olive-grey dusting, scutum viewed from behind with three faint diffused presutural wide brown vittae, scutum with major setae not arising from brown spots; scutellum olive-grey dusted, base tinged brownish. Wing membrane pale greyish tinged; veins pale brown; squamae concolorous with wing base, fringe pale yellow-white. Halteres yellow. Legs pale brown to orange-brown, coxae sometimes paler. Abdomen brown in ground colour, thinly dusted with shifting semishining patches and pale grey dusted areas, with wide diffused brown median vitta (about as wide as depth of hind femur), which becomes wider on tergite V. Prehypopygial tergites dusted.

Head: Eyes touching on frons, frontal stripe obsolete at this point, parafrontals linear, widening anteriorly but only about half width of postpedicel; parafacials medially only about half width of postpedicel, in profile almost disappearing; peristomal margin not projecting, face almost flat, distance between vibrissal setae nearly twice distance between them and nearest eye margin; gena below lowest point of eye margin narrow, 0.17–0.20× eye height; 3–4 pairs of frontal setae on anterior third of frons; 1 pair of fine interfrontal setulae at middle of frons; genal setae uniserial anteriorly; postpedicel not reaching peristomal margin (by almost its width); arista pubescent, longest hairs twice width of basal aristal diameter. Proboscis short and slender, with short prementum (not as long as palpi and as wide as fore tibia). Upper occipital setulae short and fine, without setulae below row.

Thorax: Presutural acr fine and hair-like (not differentiated from accessory setulae), biserial, acr: dc ratio 10:3:10, no hairs between rows; 2 posthumeral setae, anterior seta short and only half length of posterior seta; notopleural depression bare apart from two strong setae; prealar completely absent; scutellum bare on disc centrally and basally; anepisternite without developed upper anterior setula; katepisternals 1+2, anterior seta short, half length of upper posterior, lower posterior nearly as long as upper.

Wing: Vein C with anterior spinules short but not weak, as long as diameter of C, stronger spines before distal break nearly as long as small crossvein; lower surface of C bare. Large crossvein straight, last section of M 1+2 1.6–1.9× length of preceding section. Lower squama smaller in area than upper. Wing length 4.5–5 mm.

Legs: Mid femur with 3 unequal v or pv in proximal half; hind femur with full row of long av and shorter pv, av without curling tips; fore tibia and mid tibia with all setae short and fine, fore tibia with 1 very short ad and a slightly longer pv, mid tibia with 1 av towards apex, 1 ad, 1 pd and 2 pv, all very short and fine, not longer than diameter of tibia; hind tibia with 1–2 av, 2 ad, 2 pd, no pv setulae.

Abdomen: Dorsoventrally compressed, viewed from above parallel-sided, 3 times as long as wide; sternite III ( Fig. 33 ) long and narrow (3.75 times as long as greatest width), sternite IV nearly as long (2.2 times as long as wide); sternite V processes about as long as base, with a few short hairs on inner margins, lateral setae short, longest not longer than processes. Surstyli ( Fig. 31 ) twice as long as cercal plate, in caudal view with inner margins sinuate, widening medially then tapering apically to about half this width, clothed in fine hairs; in lateral view ( Fig. 32 ) with apical quarter downturned. Pregonite with 1–2 short setulae; postgonite triangular without setulae. Distal section of aedeagus ( Fig. 35 ) with short paraphalli which are not quite half length of section, and are converging in ventral view ( Fig. 36 ); small sclerotized acrophallus present between bases of paraphalli.

Female. Unknown.

Holotype: ♂ MADAGASCAR: ‘ Madagascar Centre / Vakaona 1520 m. / Andringitra Ambalavoa / 21– 24.i.1958 B. Stuckenberg’; ‘HOLOTYPE ♂ / Delia madagascariensis / Ackland’ [ Rectangular red card]; ‘Holotype’ [ Circular card with red perimeter]. Genitalia mounted in balsam on plastic slip on the pin ( NMSA).

Paratypes: 3 ♂ same label as holotype ( NMSA).

Discussion: D. flavibasis (which occurs in Madagascar) has no av on mid tibia, more distinct vittae on scutum with stronger acr, and discal scutellar setulae, a fine lower anterior katepisternal seta, abdominal tergites wider (tergite III 2.5–3.0 times as wide as long), margins of abdomen not parallel-sided, hind tibia with 3 pd. In addition the apex of the cercal plate in profile is broadened and projects between the base of the surstyli ( Fig. 13 ). D. madagascariensis is probably more closely related to D. bracata , which has not so far been recorded from Madagascar. D. bracata agrees with madagascariensis in having a small av on the mid tibia; most of the characters mentioned above for flavibasis also apply to bracata , including shorter and wider tergites and sternites. The surstyli however curve slightly backwards in profile, and the apical halves are distinctly narrowed. Some of the characters of madagascariensis (prealar absent, hind tibia with 2 ad and 2 pd) are the same as those described for modesta (Stein) , a species known only from Kenya and only from the original description. See under modesta for further details.

Life history: Unknown.

Distribution: Only known at present from Madagascar.

Figures

Figs 31–36. Delia madagascariensis sp. n., paratype male (Madagascar): (31) cercal plate and surstyli; (32) ditto, lateral view; (33) sternites III–V; (34) gonites; (35) distiphallus, lateral view; (36) ditto, ventral view. Scale bar = 0.1 mm.

Figs 12–16. Delia flavibasis, male (S. Africa): (12) cercal plate and surstyli; (13) ditto, lateral view; (14) sternites IV–V, ventral view; (15) distiphallus, lateral view; (16) ditto, ventral view. Scale bar = 0.1 mm.