Dilophus lucidus ( Hardy, 1948 )

Skartveit, John & Freidberg, Amnon, 2023, Revision of the genus Dilophus Meigen, 1803 (Diptera, Bibionidae) from the Afrotropical Ecozone, Zootaxa 5360 (3), pp. 301-354 : 322-323

Dilophus lucidus ( Hardy, 1948) (figs. 17–18, 93–100)

Philia lucida Hardy, 1948

Holotype (male) and paratype (female) UGANDA, Kigezi , Mt. Sabinio. Label data: ́ Mt. Sabinio / 8000ft / F.W. Edwards », ́ Allotype » (circular label with red edge) , ́ Holotype » (circular label with red edge), ́PHILIA/ lucida/ det. 1948 Hardy/ D.E. Hardy », ́BMNH (E) #/ 262992/ BMNH (E) #/ 262993», ́NHMUK 014427900 (with barcode)». Further paratypes (males): UGANDA, Kanaba , 2375m, 1 ♁ ( NHMUK). KENYA, Aberdare Range, Mt. Kinangop 2440m., x.1934, J.Ford leg, 1 ♁ ( NHMUK) .

Previous records: Kenya ( Hardy 1948), Tanzania ( Hardy 1960a), Uganda ( Hardy 1948), Rwanda ( Hardy 1950, Hardy 1955), Democratic republic of Congo ( Hardy 1950, Hardy 1952a).

Further material: ETHIOPIA, Welo, Lalibela 2470m, 8. x. 2005, 1 ♀ ( TAU), Debre Zeit, 21. ix. 2003, 1 ♀ ( TAU), Lake Davash nr. Wendo Genet, 14. iv. 2013, 2 ♁♁ ( TAU) , Homa, Bale Mts. , 2535m, 15. iv. 2013, 1 ♁ ( TAU) . KENYA: Mt. Elgon , 2800m, 31. x. 1983, 1 ♀ ( TAU) . TANZANIA, W. Usambara, Lushoto, 17.–18. viii. 2003, 1 ♀ ( TAU) , Usambara Mts. , Bumbuli 1000m, 14. ix. 1992, 1 ♀ ( TAU) . UGANDA, Rutenga , 20 km NW Kabale, 1200m, 25. xii. 1995, 3 ♁♁ ( TAU) , Mt. Muhavura 2500m, 27. xii. 1995, 1 ♁ 1 ♀ ( TAU) . MALAWI, N. Nyika NP, Zovo-Chipolo Forest , 25.–26. ix. 1998, 1 ♀ ( TAU) , N. Nyika NP, Kasaramva 2500m, 27. ix. 1998, 1 ♁ 7 ♀♀ ( TAU) , Zomba Plateau, Chiradzulu Forest, 22.–23. x. 1983, 1 ♀ ( TAU) . Previously recorded from Uganda ( Hardy 1948).

Diagnosis:A small to medium-sized (3.2–4.5 mm) species, antennal flagellum robust and 8-segmented, wing in male hyaline with invisible pterostigma, in female yellowish with pale brown pterostigma. Pronotal spine row with 12–14 close-set, small spines. Male hypopygium quadrate, gonostylus straight and blunt.

Male (fig. 17):

Total length 3.5–4.2 mm (N=3).

Head (fig. 94): Length 0.68–0.85 mm, width 0.74–0.99 mm (N=3). Complex eye nearly entirely naked. Ocellar tubercle small, quite prominent. Rostrum not at all produced. Occiput with sparse, short, pale setae. Antenna robust, somewhat clavate, flagellum 0.25–0.36 mm long, 0.08–0.11 mm wide (N=3), 8-segmented, segments strongly transverse. Underside with long, pale setae.

Thorax:Length 1.08–1.32 mm, width 0.72–0.83mm (N=4).Brownish-black,pleurae a little reddish.Dorsocentral setae short and fine. Pronotal spine row with 12 close-set, sharp, erect spines. Mesonotal spine row with 8–10 short, blunt spines on transverse row and 4–5 spines on each side more posteriorly. Scutellum with few but comparatively strong marginal setae. Haltere brown.

Legs: Reddish-brown, slender. Protibia (fig. 95) slender, with 4 curved spines on strongly oblique row, apically with 8 relatively fine spines in circlet. Mid tibia without spine-like setae. Tibiae and tarsi slender. Measurements (N=3 unless otherwise stated): fore femur 0.60–0.68 mm long, 0.21–0.23 mm wide (N=2), fore tibia 0.60–0.62 mm long, 0.08–0.09 mm wide (N=2), first fore tarsomere 0.42–0.43 mm long, mid femur 0.64–0.71 mm long, mid tibia 0.63–0.75 mm long (N=3), hind femur 0.85–1.11 mm long, 0.14–0.18 mm wide, hind tibia 0.91–1.09 mm long, 0.09–0.11 mm wide, first hind tarsomere 0.28–0.40 mm long.

Wing (fig. 93): Length 2.95–3.81 mm, width 1.02–1.25 mm, length/width = 2.84–3.06 (N=4), hyaline with fairly strong microtrichia. Pterostigma colourless. R-veins and stem of M yellowish, posterior veins colourless. Costa with rather strong setulae, extending to 0.3* distance between apices of R 4+5 and M 1. Humeral vein absent. Subcosta colourless but fairly distinctive. R 1 apically colourless. Basal part of Rs about 0.25*R-M. R 4+5 almost straight. Fork of M asymmetrical. M-Cu joins M at furcation. Fork of CuA moderately wide, CuA 1 woth a small kink at M-Cu. CuA 2 apically nearly straight. CuP and A 1 indistinctive.

Abdomen: Brownish-black, shiny, sparsely clad with short setae.

Terminalia: Hypopygium (figs. 96–97) width 0.28–0.37 mm (N=3), almost quadrate in outline. Gonostylus 0.16–0.17 mm long (N=2), straight, not at all expanded apically, blunt. Epandrium rather narrow, rectangular, apically slightly concave. Ventral indentation of gonocoxosternite wide and shallow, W-shaped.

Female (fig. 18):

Total length 3.2–4.6 mm (N=8).

Head (fig. 99): Length 0.66–0.83 mm, width 0.47–0.58 mm (N=8). Blackish-brown, rather elongate. Part behind complex eye roughly similar to eye diameter. Ocellar tubercle small. Posterior part with few short, fine setae. Frons slightly concave between complex eyes. Complex eye a little prominent. Antennal flagellum 0.25–0.36 mm long, 0.08–0.11 mm wide (N=8), stout, 8-segmented, segments strongly transverse. Head exenteds about one half eye diameter in front of complex eye. Palp short, last segment cylindrical.

Thorax: Length 1.21–1.68 mm, width 0.58–0.87 mm (N=8). Reddish-yellow with black dorsal stripe, anterior margin of meron brown. Dorsocentral setae quite short. Scutellum with very short, marginal setae. Pronotal spine row with c. 14 close-set, sharp, erect spines. Mesonotal spine row with c. 14 short spines on transverse, raised ridge.

Legs: coxae and femorae reddish-yellow, tibiae and tarsi dark brown. Fore tibia (fig. 100) with 4 spines on sligthly oblique, mesal row, apically with 8 spines in circlet. Mid tibia without spinelike setae. Tibiae and tarsi slender. Measurements (N=8 unless otherwise stated): fore femur 0.53–0.70 mm long, 0.24–0.30 mm wide, fore tibia 0.51–0.70 mm long, 0.08–0.13 mm wide, first fore tarsomere 0.32–0.43 mm long, mid femur 0.57–0.79 mm long (N=6), mid tibia 0.58–0.77 mm long (N=7), hind femur 0.91–1.11 mm long, 0.13–0.21 mm wide, hind tibia 0.92–1.19 mm long, 0.10–0.14 mm wide, first hind tarsomere 0.36–0.51 mm long.

Wing (fig. 98): Length 3.58–3.89 mm (N=7), width 1.17–1.36 mm (N=8), length/width = 2.78–3.14 (N=7), slightly yellowish-brown fumose, pterostigma light brown and oval. With strong microtrichia. R-veins and stem of M brown, posterior veins yellowish. Venation as in male.

Abdomen: Dark brown, shiny. Cerci rounded.

Distribution and ecology: The species is widely distributed in East Africa from Ethiopia in the north to Malawi in the south. It has been collected between 1000–2800 m altitude from forested localities.

Flight period: the available specimens have been collected between August and April ( Table 2 ).