Dilophus vicarius ( 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 : 308

Dilophus vicarius ( Hardy, 1948) ( Figs. 3 , 35–39 )

Philia vicaria Hardy, 1948

Holotype (male) UGANDA, Kigezi , Mt. Mgahinga 3000–3300m Label data: ́ Mt. Mgahinga / 10,000–11,000 ft / F.W. Edwards », ́ xi.1934 / B.M.E.Afr.Exp /B.M. 1935-203», ́UGANDA:/Kigezi Distr./ F.W. Edwards. », ́Holotype» (circular label), ««Holotype ♁/ Philia/ vicaria/ D.E.Hardy » (handwritten on pink label), «PHILIA/ vicaria / det. 1948 Hardy/ D.E. Hardy », ́BMNH (E) # / 252986» and ́NHMUK 014427899» (with barcode) ( NMHUK). Paratypes (5♁♁) same data as holotype.

Previous records: Uganda ( Hardy 1948), Rwanda ( Hardy 1950, Hardy 1955), Democratic Republic of Congo ( Hardy 1950).

Other material: BURUNDI, Kayanza, P.N. de la Kibira, 21.–26. xi. 2010 2 ♁♁ 1 ♀ ( NMSA) , Kayanza, P.N. de la Kibira, Rwegura 2100m, 28–30.i. 2011, 3 ♁♁ ( TAU) .

Diagnosis: This medium-sized, slender species is easily recognized by the fore tibia, which is very slender with 2+2 small mesal spines.

Male (fig. 3):

Head (fig. 36): Complex eye large, almost bare, with a few very short, pale intraocular setae. Occiput with medium-length, yellowish setae. Underside of head with sparse, rather short, brownish setae. Rostrum not at all produced beyond complex eye. Ocellar tubercle small but prominent. Antenna brownish-black, flagellum stout, cylindrical, 6-segmented. Palp short, brown, last segment relatively slender, cylindrical.

Thorax: Pronotum and mesonotum black, pleura brown, moderately shining with reticulate microsculpture. Notum strongly domed. Dorsocentral setae irregularly biserial, short, pale. Setae on sides of mesonotum fine, rather dense, pale. Pronotal spine row with 12 fine, sharp, erect spines, mesonotal spine row with 14 fine, sharp spines. Haltere with yellow stem and dark-brown knob.

Legs: All coxae and femorae pale yellowish, tibiae and tarsi brownish-black with sparse, rather short, pale pile. Fore tibia (fig. 37) very slender, cylindrical, with 2+2 small, mesal spines, 8 spines in apical circlet. Hind femur slightly curved and clavate, all tibiae and tarsi slender.

Wing (fig. 35): hyaline with a pearly sheen, anterior veins pale yellowish, posterior veins colourless. Costa basally with some long, pale setulae, setulae decreasing in length apicad, in outer half shorter than the width of costa, which extends to a little past half-way between apices of R 4+5 and M 1. Humeral vein absent. Pterostigma unpigmented. Subcosta fine, colourless, distinctive basally only. R s about one-third the length of R-M. R 4+5 gently curved. M basally connected to CuA. Fork of M asymmetrical, M-M 2 forming a straight line with M 1 diverging forward from this. M 1 and M 2 apically diverging. M-CuA joins M a little basad of furcation. Fork of CuA short and broad, CuA 1 and CuA 2 apically a little curved basad. CuP indistinctive.

Abdomen: Black, shiny, with very sparse, short, pale pile.

Terminalia: Hypopygium (figs. 38–39) 0.35–0.36 mm wide (N=2), rounded in outline, wider than long. Gonostylus strong, straight, blunt with a distinctive ́head». Epandrium large, posterior margin strongly concave, apically with a dense fringe of strong, yellowish setae, otherwise clad with setae of medium length and density. Ventral indentation of gonocoxosternite rather shallow, broadly W-shaped.

Female not studied. The single female specimen listed was seen by the first author before the initiation of this study and has been returned to its collection.

Distribution and ecology: The species is distributed in Central Africa, known from Democratic Republic of Congo, Rwanda ( Hardy 1950), Uganda and Burundi. It is a montane species which has been found at altitudes between 1750–3900m ( Hardy 1950).

Flight period:The few available records are scattered over much of the year, but none in June–August ( 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 35–39. Dilophus vicarius (Hardy, 1948). 35. Male, wing. 36. Male, head and thorax. 37. Male, fore tibia. 38. Male, terminalia, dorsal. 39. Male, terminalia, ventral.