Dilophus

Skartveit, John & Freidberg, Amnon, 2023, Revision of the genus Dilophus Meigen, 1803 (Diptera, Bibionidae) from the Afrotropical Ecozone, Zootaxa 5360 (3), pp. 301-354 : 304-305

Key to the species of the genus Dilophus found in the Afrotropical ecozone

1. Fore tibia with two groups of mesal spines, one in the basal half and one near the middle (figs. 28, 34, 37).............. - 2 Fore tibia with just one group of mesal spines near the middle ( Dilophus febrilis -group)............................ - 3

2. Fore tibia with 1 + 2–3 large, erect spines (figs. 28, 34)............................................ Dilophus nuptus Fore tibia with 2 + 2 small spines (fig. 37)..................................................... Dilophus vicarius

3. Larger species, ca. 6–8mm. Wing more or less dark fumose................................................... -4 Smaller species, at most 5 mm. Wing not dark fumose. Male gonostylus without apical notch, setae not particularly long and dense.............................................................................................. - 5

4. Wing dark fumose in both sexes. Male gonostylus with an apical notch and dense, long setae (figs. 122, 123). Wing length 4.5–6.2 mm ............................................................................. Dilophus bicolor Wing yellowish-brown fumose. Wing length c. 6 mm. Female only known........................... Dilophus buxtoni

5. Haltere yellowish-white. Male coxae and femorae yellowish...................................... Dilophus disagrus Haltere brown to blackish. Male coxae and femorae dark..................................................... - 6

6. Costa ending at or just beyond apex of R 4+5 (figs. 85, 90)....................................... Dilophus erythraeus Costa extends considerably beyond apex of R 4+5 ............................................................ - 7

7. CuA 1 terminates well before edge of wing (figs. 101, 106)....................................... Dilophus obsoletus CuA 1 extends to edge of wing (figs. 93, 98)................................................................. 8

8. Rostrum somewhat produced before eye margin, in male about as long as one-half the diameter of lower part of complex eye (figs. 78, 110)....................................................................................... - 9 Rostrum not at all extending forward from complex eye..................................................... - 10

9. Male with whitish pile on thorax, female mesonotum red with black mesal stripe. Protibial spines rather long (figs. 111, 115).................................................................................. Dilophus suberythraeus Male with dark pile on thorax, female mesonotum black. Protibial spines very short (figs. 79, 84) ........ Dilophus capensis

10. Body with dense, long, yellowish to gray pubescence............................................ Dilophus atrimas Body nearly naked, not conspicuously pubescent........................................................... - 11

11. Small species, male wing length 2.4–2.6 mm, head without conspicuous interocular pile. Posterior wing veins colourless. Female unknown....................................................................... Dilophus paucidens

Larger species, wing length at least 3.0 mm. Male complex eye with visible interocular pile. Male posterior wing veins with at least some pigmentation.............................................................................. - 12

12. Male gonostylus apically blunt, with distinctive ́head» (fig. 51). Female with mesal protibial spines large and erect (fig. 55)....................................................................................... Dilophus riftensis Male gonostylus apically pointed, with ́beak» (figs. 43, 64). Female with mesal protibial spines smaller and less erect (figs. 47, 68)............................................................................................ - 13

14. Male wing with pterostigma invisible. Female with hind femur and tibia both reddish-brown, tibia little darker than femur......................................................................................... Dilophus lucidus

Male wing with pterostigma dark brown, distinctive. Female with hind femur mostly yellowish, tibia black.................................................................................................... Dilophus baleensis