Delia andersoni ( Malloch, 1924 )

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 : 53-56

Delia andersoni ( Malloch, 1924)

Figs 84–90 , 99

Hylemyia andersoni Malloch, 1924 b: 262 , 264; Curran 1929: 247;? Cuthbertson 1932: 32; Emden 1941 b: 266; 1951: 333, 359.

Delia andersoni (Malloch) : Pont & Ackland 1980: 716.

Diagnosis:

♂ Arista practically bare, longest hairs shorter than basal diameter; eye margins on frons almost touching; occiput below upper occipital row bare; prealar seta absent; presutural acr fine and hair-like, rows close together without hairs between rows; large crossvein almost straight; fore tibia with a short pointed pv apical seta; ad on mid tibia short or absent, only one pd seta.

Description:

Male.

Colour: Frontal stripe, parafrontals, parafacials, genae and face varying from blackish to orange in ground colour, with thin greyish dusting; parafacial at level of aristal base orange to blackish, viewed from above silvery white dusted, occiput dark grey.Antennae brownish black. Palpi brown; prementum of proboscis dark brown with thin grey dust, hence somewhat shining. Thorax dark in ground colour, with grey dusting, scutum viewed from behind with wide median vitta (wider than acr rows), traces of narrow dark vittae along dc rows (sometimes absent), and wider lateral vittae, all more distinct presuturally, very faint postsuturally. Scutellum with trace of brown median vitta. Abdomen dark brown in ground colour, with shining patches when viewed from above, densely greenish grey dusted when viewed from behind, with distinct wide brown median vitta (about as wide as depth of hind femur). Prehypopygial tergites grey dusted. Wing membrane pale brownish tinged in basal half; veins pale brown; squamae paler than wing base. Legs brown to orange-brown, slightly shining.

Head: Eyes separated by less than diameter of anterior ocellus, frontal stripe and parafrontals linear at narrowest point between eyes; parafacials medially 0.6–0.8× width of postpedicel; peristomal margin hardly projecting; gena below lowest point of eye margin 0.20–0.22× eye height; face almost flat, distance between vibrissal setae more than distance between them and nearest eye margin; 4 pairs of parafrontal setae; 1 fine pair of interfrontal setae; genal setae uniserial anteriorly (with 1 seta placed above row). Postpedicel twice as long as wide, not reaching peristomal margin by half its length; arista almost bare, longest hairs less than basal diameter. Prementum short (not as long as palpi) and as wide as fore tibia. Palpi slender. Occiput with upper occipital setulae moderately long and fine without setulae below row.

Thorax: Presutural acr fine and hair-like (not differentiated from accessory setulae), biserial, acr: dc ratio 10:2:10, no hairs between rows; 2 posthumeral setae; notopleural depression bare apart from two strong setae; prealar completely absent, or sometimes fine hair is present; scutellum bare on disc centrally and basally; anepisternite without developed upper anterior setula; katepisternals 1+2 (sometimes short hair below anterior seta), lower posterior 0.7 times as long as upper.

Wing: Vein C with anterior spinules 1.25–1.5 times as long as diameter of C, stronger spines before distal break as long as small crossvein; lower surface of C bare. Large crossvein almost straight, last section of M 1.6–1.7× length of preceding section. Lower squama smaller in area than upper. Wing length 4.25–4.5 mm.

1+2

Legs: Hind femur ( Fig. 90 ) with 4–7 av in distal half, 1 apical pv; fore tibia with short fine pointed apical pv, and 1 ad, 1 pd, 1 pv, all short; mid tibia with very small ad (sometimes absent), only 1 pd, 2 pv; hind tibia with 2 av, 4 ad, 3 pd, 1–2 short pv.

Abdomen: About 2.5 times as long as greatest width (at basal margin of sternite III), parallel sided, dorsoventrally compressed; sternite IV ( Fig. 86 ) as wide as base of sternite V, quadrilateral, with only short setulae; sternite V ( Fig. 86 ) rather large, and projecting downwards in lateral view, processes 1.5× length of base, widened medially, with a few short fine hairs on inner margins, lateral setae ( Fig. 87 ) not longer than processes. Surstyli ( Fig. 84 ) 1.8–1.9× length of cercal plate, in caudal view expanded medially, then tapering and converging towards apices, inner margins sinuate, clothed with fine hairs, in lateral view ( Fig. 85 ) slender, angled basally, apical half with expanded flange on posterior margin. Cercal plate ( Fig. 84 ) heart-shaped, 1.2× longer than wide, narrowly heartshaped, apex pointed, bearing a few short setae. Pregonite with 2 setae; postgonite triangular without setae. Aedeagus with distal section ( Figs 88, 89 ) 2.5 times as long as aedeagal apodeme, without free paraphallic processes; in lateral view extremely slender, apically membranous and bearing 8–12 spicules. Aedeagal apodeme slender in lateral view, in dorsal view 2.6 times as long as greatest width, constricted medially, distal end joining phallophore rather wide. Ejaculatory apodeme half as long as aedeagal apodeme, long and slender.

Female. Similar to male, except for the following:

Colour: Parafrontals grey dusted but darkened brown between orbital setae row and eye margin; gena with shifting darker patch on anterior half which in certain lights reaches from eye margin to vibrissal seta; anepisternite with suffused brownish patch anteriorly; scutum more distinctly 5-vittate than male, dc lying on distinct narrow vitta and arising from dark spots; abdomen with distinct brown median vitta, wider basally on tergites forming triangles, bordered by shifting grey dust, especially when viewed from behind; vitta on tergite V not reaching posterior margin. Head: eyes widely separated by 1.5–1.6× their transverse width; frontal stripe at level of middle orbitals twice as wide as each parafrontal; parafacial widening anteriorly to slightly more than width of postpedicel; parafrontal setae differentiated into 3 pairs of orbitals (all more or less exclinate), and 2 pairs of frontal setae; crossed interfrontals strong, and placed at apex of frontal triangle; gena below lowest point of eye margin 0.35× eye height.

Thorax: acr very fine and short (as in male); katepisternals 1+1; prealar seta absent, or in some specimens represented by short setula. Wing length 4.5 mm.

Legs: All setae stronger and longer than in male. Hind femur with 3–4 av in distal half, 1 preapical pv; fore tibia with 1 av and 1 pv; mid tibia with 1 long and strong ad, a slightly shorter pd at same level, 2 pv; hind tibia with 2 av, 4 ad, 3 pd, no pv hairs or setulae.

Abdomen: Slightly longer than thorax (1.15×), dorsoventrally compressed, viewed from above widest at anterior margin of tergite II where it is half as wide as long; hind marginal setae on tergites short and weak (not longer than half length of each tergite), and not erect. Postabdomen ( Fig. 99 ) practically identical to D. bracata .

Holotype: ♂ ‘Holotype’ [circular label with red perimeter]; ‘N. of Mt Kenia / 8,300 ft / 18.2.11 / Brit. E. Africa’ [rectangular white label]; ‘ T. J. Anderson’ [rectangular white label]; ‘Pres. by Inst. Bur. Ent. Brit. Mus. 1924–242’ [rectangular white label]; ‘ Hylemyia andersoni / det. J. R. Malloch, Type’ [rectangular white label with black perimeter] ( BMNH) . Holotype in good condition, but antennae missing (as noted by Malloch), also right mid and hind legs missing.

Other material examined: ETHIOPIA: 1 ♂ Addis Ababa, Entotto , alt. 3000 m, 17.x.1968, R. Kano & T. Ohse ( DMA) . KENYA: 2 ♂ 1♀Aberdare Range, Nyeri Track , alt. 10500 ft, 28.x.1934, J. Ford ( BMNH); 1 ♂ Aberdare Range , Mt Kinangop (1º05'N: 34º40'E), alt. 10000 ft, 26.x.1934, F.W. Edwards ( BMNH); 1 ♂ 13♀Mt Elgon, alt. 10250 ft, 24–25.i.1972, C.F. Huggins ( BMNH); 1♀Chyulu Hills, Tsavo West Nat. Park , 24–26.ix.1971, C.F. Dewhurst ( BMNH); 1 ♂ Muguga, nr Nairobi , 6–12.i.1969, M.C. Birch ( DMA) ; UGANDA: 1 ♂ Imatong Mts , alt. 10000 ft, ii.1936, D.R. Buxton ( BMNH); 1 ♂ Mt Elgon, between Butandiga & Bulambuli , alt. 8000 ft, 7.viii.1934, J. Ford ( BMNH) .

Life history: Cuthbertson (1932: 32) reported the occurrence of D. andersoni in Zimbabwe “collected in cattle kraals, vleis etc., at Salisbury, Gatooma and Balla Balla during the wet season. Larvae were found in some stems of rapoko (a cereal), Eleusine coracana , sent from Domboshava Mission in March, 1932”. There is a female of D. flavibasis in the BMNH with the following labels “ 1♀Domboshava, iii.1932, larvae in stems of rapoko ( Eleuscine coracana ) with larvae of Hylemyia andersoni Mall. , det. Hylemyia arambourgi Ség. by Emden, 1940.” I have not been able to trace any other material from this locality, and more evidence is required before this record can be accepted.

Distribution: D. andersoni is only known from Ethiopia, Kenya, Uganda. Curran (1929: 247) recorded this species from Kivu, Belgian Congo, now Democratic Republic of the Congo, but this record needs confirmation.

Figures

Figs 84–90. Delia andersoni, male (Kenya): (84) cercal plate and surstyli; (85) ditto, lateral view; (86) sternites IV–V; (87) sternite V, lateral view; (88) distiphallus, lateral view; (89) ditto, lateral view; (90) hind femur. Scale bar = 0.1 mm.

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.