Delia ismayi, 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 : 34-36

Delia ismayi sp. n.

Figs 37–43

Etymology: I name this species after Dr J.W. Ismay, who collected this species in Kenya, and provided all of the Anthomyiidae he found in Africa and on many other expeditions he made to other parts of the world.

Diagnosis:

♂ Major scutal setae arising from small brown spots; eye margins practically touching on frons; scutal accessory setulae very sparse, short and fine; prealar absent; mid tibia without av; tergites III and IV shortened on posterior margin; sternite III ( Fig. 40 ) with long erect setae laterally on posterior margin; distiphallus ( Fig. 43 ) with long narrow paraphalli.

Description:

Male.

Colour: Frontal stripe, parafrontals, parafacials, genae and face brownish orange to blackish, thinly dusted whitish grey; occiput dark grey to blackish, thinly dusted and semi-shining. Antennae dark brown. Palpi dark brown; prementum brownish, thinly dusted. Thorax and scutellum brownish grey in ground colour with thin dusting, pleurae orange-brown translucent in places, scutum with very obscure wider or narrower darker vittae, major setae arising from small brown spots; viewed from behind with narrow paler vittae along dorsoventral rows. Abdomen with ground colour as thorax, viewed from behind grey dusted with wide brown median vitta which is narrowly extended across base of tergites, and also widened posteriorly on each tergite. Prehypopygial tergites and epandrium dusted as rest of abdomen. Wing membrane light greyish tinged; squamae whitish grey (slightly lighter than wing base), veins light brownish. Legs brown to blackish, tibiae often paler orange-brown.

Head: Eye margins on frons practically touching, separated by less than diameter of anterior ocellus. Frontal stripe linear at this point; parafacial at narrowest part 0.75× width of postpedicel; peristomal margin not projecting, behind level of profrons; gena about 0.23× eye height; 4–5 pairs of parafrontal setae on anterior half of frons; 1 pair of very small interfrontal setulae; genal setae uniserial. Postpedicel not quite twice as long as wide, not reaching peristomal margin, arista pubescent, longest hairs not as long as basal diameter, base not abruptly swollen but tapering gradually to apex. Proboscis small and narrow, prementum hardly as long as palpi and only as wide as fore tibia. Upper occipital setulae short and fine, without setulae below row.

Thorax: Accessory setulae very sparse, short and fine. Presutural acr short and fine, biserial, rows separated by 0.5× distance between acr and dc rows, no hairs between rows; posthumeral setae 1+1; notopleural depression bare apart from two strong setae; prealar absent or represented by fine hair which is hardly distinguishable from accessory setulae; scutellum practically bare on disc apart from two fine lateral setulae; anepisternite without an upper developed setula; 2 proepisternals, 1 proepimeral with 1–2 associated hairs, katepisternals 1+2, lower posterior three quarters length of upper posterior seta. Wing: Vein C with anterior spinules short and weak (not longer than diameter of C), normally stronger setae before distal break only slightly longer than vein diameter; lower surface of C bare. Large crossvein straight, joining M 1+2 almost at right angles, last section of M 1+2 twice length of preceding section. Lower squama smaller in area than upper, not projecting. Wing length about 4 mm.

Legs: Slender, all setae short and weak. Mid femur with 3–4 longer pv in basal half; hind femur with 4–5 av in distal half, median setae short, becoming longer apically, no pv except for 1–2 apicals; fore tibia with a short fine pointed preapical pv, with 1 short ad and 1 slightly longer pv at about same level; mid tibia without av, 1 ad and 1 pd, both very short and fine, not longer than diameter of tibia; hind tibia with 2 av, 4 ad, 3 pd, 0–1 pv. Pulvilli on fore legs as long as fore tarsomere 5.

Abdomen: About as long as thorax, in dorsal view about 3 times as long as greatest width, dorsoventrally compressed; tergites III and IV short and posteriorly excavated, separated from each other and from tergites II and V by wide areas of flexible intersegmental cuticle; sternite III ( Fig. 39 ) slightly longer than width at posterior margin, narrower on basal margin, with long setae on posterior corners, curling tips of which reach posterior margin of sternite IV; these setae are more or less divided by much shorter finer hairs medially on posterior margin; in lateral view ( Fig. 40 ) they project more or less at right angles to abdomen. Sternite IV ( Fig. 39 ) wide, quadrilateral with rounded lateral margins, and only with rather sparse lateral fine setulae, medially bare; sternite V ( Fig. 39 ) with tapering processes, without setae on inner margins, lateral setae not longer than processes. Surstyli in caudal view ( Fig. 37 ) twice as long as cercal plate, widened medially, gradually tapering to apex, dorsal surface laterally with fine hairs, in lateral view strongly bent in basal half ( Fig. 38 ), then more or less straight and parallel-sided to apex. Cercal plate ( Fig. 37 ) 1.25 times as long as wide, tapering sides with narrowly rounded apex, which bears two longer setae (as long as length of cercal plate). Pregonite with 2 distal setae; postgonite without distinct seta. Aedeagus ( Figs 42, 43 ) with distal section 1.7 times as long as aedeagal apodeme, divided on more than distal half (1.6) into pair of long and straight slender paraphallic processes.Acrophallus absent.Aedeagal apodeme more or less flat, 3 times as long as wide in dorsal view, and very narrow at point of attachment to phallophore. Ejaculatory apodeme very small, widened at one end.

Female. Unknown.

Holotype ♂: KENYA: ‘Holotype’ [circular white label with red perimeter]; ‘KENYA: Karasani / 10.viii.89, swept / savannah, J.W. Ismay’ [rectangular white printed label]; ‘HOLOTYPE / Delia / ismayi ♂ / D. M. Ackland’ [rectangular white printed and written label with red border] ( OUMNH). In good condition.

Paratypes: KENYA: 4 ♂ same data as holotype ( OUMNH) ; 1 ♂ Ngong Hills , vi.1946, van Someren (V.G.L. van Someren collection, British Museum, 1959-468; Imp. Inst. Ent. Coll. No 10720), det. Hylemyia ventralis Stein, van Emden, 1947 ( BMNH) . SOUTH AFRICA: North West: 2 ♂ Rustenburg , 3.xii.1961, F. Zumpt ( NMSA) ; 1 ♂ Potchefstroom , 27.1.1951, F. Zumpt ( BMNH) . KwaZulu-Natal: 1 ♂ Weenen Nat. Res. , 28°51'S: 29°59'E, thornveld, mercury vapour light, 3.x.1990, Whittington ( NMSA) .

Discussion: D. ismayi has been misidentified as D. ventralis by Emden (as listed above). I have not been able to find the specimen he recorded as ‘ Hylemyia ventralis ’ from Natal, Weenen, vi–vii.23, H.P. Thomasset (Emden 1951: 362) which he stated was in the BMNH. This also probably belongs to D. ismayi , as D. ventralis appears to be restricted to the mountains of central Africa. See under the phylogeny of the D. ventralis subsection for notes on the ventral setae on sternite III.

Life history: Unknown.

Distribution: Known only from Kenya and South Africa.

Figures

Figs 37–43. Delia ismayi sp. n., male paratype (Kenya): (37) cercal plate and surstyli; (38) ditto, lateral view; (39) sternites II–V: (40) sternites III–V, lateral view; (41) gonites; (42) distiphallus, lateral view; (43) ditto ventral view. Scale bar = 0.5 mm.