Dilophus nuptus ( Speiser, 1914 )

Skartveit, John & Freidberg, Amnon, 2023, Revision of the genus Dilophus Meigen, 1803 (Diptera, Bibionidae) from the Afrotropical Ecozone, Zootaxa 5360 (3), pp. 301-354 : 305-307

Dilophus nuptus ( Speiser, 1914) ( Figs. 1–2 , 26–34 )

Philia nupta Speiser, 1914

Type locality: CAMEROON, Dschang. Location of type is unclear.

Previous records: Kenya ( Hardy 1951a), Tanzania ( Lindner 1958, Hardy 1960a), Uganda ( Hardy 1948, Hardy 1951a), Malawi ( Hardy 1951a), Burundi ( Hardy 1952c), Democratic republic of Congo ( Hardy 1950, Hardy 1951a, Hardy 1952a, Hardy 1952b), Zambia ( Hardy 1951a), Cameroon ( Speiser 1914), Ghana ( Hardy 1951a).

Material examined: ETHIOPIA, Gonder, Gonder 2150m, 1. x. 2005, 6 ♁♁ 2 ♀♀ ( TAU) , Gojam, Bagdo Mikael 2650m, 29. ix. 2005, 1 ♁ ( TAU) . KENYA, Kakamega Forest , 1525m, 23. ix. 2005, 1 ♁ ( TAU) , Taita Hills , viii.1947, van Someren leg., 3 ♁♁ ( NHMUK) . UGANDA, Budongo Forest , site 7, 19.–21. vii. 2010, G.M. Kvifte leg., 1 ♀ ( ZMUB) , Budongo Forest , site 1, Malaise trap, 16.–19. vii. 2010, G.M. Kvifte leg., 1 ♀ ( ZMUB) , Kampala, 27. v. 1933, H. Hargreaves leg., 5 ♀♀ ( NHMUK) , Ruwenzori Range, Kilembe , 1370m, xii.1934 – i.1935, 1♁ 1♀ ( NHMUK) , W. Uganda, Bwambwa Country , 1938, J.O. Harper leg 1 ♁ ( NHMUK) . BURUNDI, Kayanza, Kibira NP, Rwegura 2100m, 28–30.i. 2011, 1 ♁ ( TAU) . ZAMBIA, Serembe, Chitambo , 1510m, 1928, D. Hewitson leg ( NHMUK) . ZIMBABWE, Salisbury (= Harare), 18.iii.1927, A. Cuthbertson leg,, 1♁ 1♀ ( NHMUK) . CAMEROON, Rhumiski , 9. viii. 2013, 1 ♁ ( TAU) . GHANA, Ashanti, Obuasi , 7. vii. 1907, 1 ♁, 16.vii.1907, 1♁ 2♀♀, 28.vii. 1907, 1 ♁, 1907 (no date) 1♁, all W.M. Graham leg ( NHMUK) .

Diagnosis: This large and colourful species is easily recognized by its protibia with 2+1 very strong, erect mesal spines.

Male: (fig. 1) Black, shiny, sparsely pilose, wing brown fumose.

Head (fig. 27): Complex eye with very sparse and short, intraocular pile, almost bare. Occiput with rather strong, medium-length, proclinate setae. Ocellar triangle rather small but prominent. Rostrum scarcely produced beyond complex eye. Underside of head with few, long setae in distal half, basal half with short pile only. Labellum with rather dense, strong, dark setae. Flagellum brownish-black, slender, conical, with 12–13 flagellomeres. Palp black,rather stout, last segment cylindrical.

Thorax: Prothorax yellow, otherwise black, shiny. Anterior part of mesonotum sparsely setose with short, reclinate setae, posterior part with longer and denser, proclinate setae. Sides of mesonotum with strong, longitudinal microsculpture and strong, dark setae. Notum strongly domed. Pronotal spine row with 12 short spines, mesonotal spine row with about 14 short spines. Dorsocentral setae irregularly biserial. Haltere blackish-brown.

Legs: Fore coxa and alle femora yellowish, mid- and hind coxae brown, fore tibia reddish-brown, mid- and hind tibiae and all tarsi brownish-black. All parts of legs with medium-length, dark pile. Protibia (fig. 28) short and stout, expanding a little apicad, with 2 +1 strong, erect mesal spines and 6 strong spines in apical circlet. Hind femur clavate, hind tibia robust, evenly expanded apicad, with short, sharp, curved spurs, hind first tarsomere globose, as wide as apex of tibia (fig. 29).

Wing (fig. 26): Brown fumose, anterior veins dark brown, posterior veins light brown. Costa with sparse setulae about as long as the width of costa, no longer setulae near base, extends to half-way between apices of R 4+5 and M 1. Humeral vein absent. Pterostigma brown, oval, not strongly contrasting against membrane. Subcosta yellowish-brown, fine but distinctive, costal cell yellowish-brown, darker than rest of membrane. R s about one-third the length of crossvein R-M. R 4+5 gently curved. M basally connected to CuA by a very fine, dark vein. Fork of M strongly asymmetrical, M-M 2 forming a straight line, M 1 diverging forward from this. M 1 and M 2 apically parallel. M-CuA meets M at furcation. CuA/CuA 2 strong, yellowish. Fork of CuA wide, CuA 1 kinked at M-CuA, otherwise straight, CuA 2 apically gently curved basad. CuP fine, does not reach wing margin. A 1 basally distinct as a hook-shaped vein.

Abdomen: Cylindrical, quite slender, black with sparse, long, dark pile. Tergites with rather strong, reticulate microsculpture.

Terminalia: Hypopygium (figs. 30, 31) outline rectangular. Gonostylus rather slender, apically truncate with an almost vertical apical surface. Epandrium rectangular with a straight posterior edge, sparsely clad with medium-length setae. Gonocoxosternite entirely divided by mesal, V-shaped cleft.

Female (fig. 2):

Head (fig. 33): Black, very smooth and shiny, mostly nearly bare. Occiput with coarse, brownish setae. Ocellar triangle medium-sized, fairly prominent. Frons clearly concave between complex eyes, with a bit irregular, longitudinal sculpture, entirely bare. Complex eye relatively large (more than half length of head), oval, entirely bare. Underside of head with short, yellowish setae. Rostrum extends a little less than half eye diameter in front of complex eye. Labellum and palp with strong, brown setae. Antenna much stouter than in male, cylindrical, flagellum compact with about 12 segements.

Thorax: Pronotum reddish-brown, pleura with a brown spot extending from wing base forward to fore coxa, lower end of meron dark brown, otherwise yellowish-orange. Mesonotum with sparse, pale dorsocentral setae. Sides of mesonotum with fine, reticulate microsculpture and fine, short, pale setae. Pronotal spine row with 12 strong, erect, blunt spines, mesonotal spine row with about 12 strong, rather large, blunt spines. Haltere dark brown.

Legs: Fore coxa and all femorae reddish-yellow. Mid- and hind coxae yellowish-brown, fore tibia reddish-brown, mid- and hind tibia and all tarsi brown. Fore tibia (fig. 34) very stout, expanding apicad, with 2+1 very strong, erect mesal spines, apical circlet with 6 strong spines. Legs moderately robust, hind first tarsomere robust but not notably thickened.

Wing (fig. 32): Slightly paler than in male, otherwise similar in colour and venation.

Abdomen: Blackish-brown, cylindrical, moderately shiny.

Terminalia: Last sternite brownish-yellow with brown lobes on genital fork. Cercus rather large, squareended.

Distribution and ecology: The species is widely distributed in tropical Africa south to Zimbabwe. It is apparently moderately montane and has been recorded at altitudes between 1370–2650 m.

Flight period: The species has been recorded throughout the year ( Table 2 ).

Figures

FIGURES 1–4. 1. Dilophus nuptus(Speiser, 1914), male, habitus. 2. Dilophus nuptus (Speiser, 1914), female, habitus. 3. Dilophus vicarius (Hardy, 1948), male, habitus. 4. Dilophus baleensis sp.n., male, habitus.

FIGURES 26–29. Dilophus nuptus (Speiser, 1914). 26. Male, wing. Wing notation, abbreviations: bM - basal section of M, dM - distal section of M, h - humeral vein. 27. Male, head and thorax. 28. Male, fore tibia. 29. Male, hind leg.

FIGURES 30–34. Dilophus nuptus (Speiser, 1914). 30. Male, terminalia, dorsal view. 31. Male, terminalia, ventral view. 32. Female, wing. 33. Female, head and thorax. 34. Female, fore tibia.