Key to species of African Gymnochiromyia

1 Metanotum black or brown contrasting with pale adjacent sclerites; hypl darkened .............................................................................................................................. 2

– Metanotum yellow, if darker, not clearly contrasting with adjacent sclerites; hypl pale, only at base of haltere sometimes darker ..................................................... 5

2 Mesonotum with brown or black stripes .............................................................. 3

– Mesonotum not striped ......................................................................................... 4

3 Most of lateral margin of scut dark; ep dark; ♂ with brown mark in anterior half of apical third of wing; ♀with brown spot laterally at the middle of the third antennal segment; setae on head and thorax very long: anterior orb as long as width of fr at same level, posterior orb longer than height of eye, prescutellars as long as scut; ♂ postabdomen, Fig. 19 ............................................................... nubilipennis sp. n.

– Only basal part of lateral margin of scut dark; ep often yellow (variable); wing entirely hyaline; ♀with third antennal segment entirely yellow; setae on head and thorax of normal length: anterior orb about half as long as width of frons at same level, posterior orb distinctly shorter than height of eye, prescutellars about 1/3 as long as scut; ♂ postabdomen, Fig. 5, ♀, Fig. 7 ............................... capensis sp. n.

4 1+3 dc, tergites shiny, ep brown, acrs in six rows; ♂ postabdomen, Fig. 26 .......................................................................................................... turneri sp. n.

– 0+2 dc, tergites matt, ep yellow with brown midline spot just above cerci and narrow brown transverse band along anterodorsal edge near tg 6 (Fig. 2d), acrs in eight rows; ♂ postabdomen, Fig. 3, ♀, Fig. 4 ........................................... balteata sp. n.

5 The following character states present simultaneously: msn with two stripes, acrs in four rows, ep yellow without spots, apical segments of ♀abdomen without spots; ♂ postabdomen, Fig. 17, ♀, Fig. 18 ................................................... milleri sp. n.

– msn without stripes, acrs in 6–8 rows (except in some specimens of gilva and megacephala where rows may be reduced to 4–6) ............................................... 6

6 Males .................................................................................................................... 7

– Females (note: females of gilva, malagasica & stuckenbergi are unknown) ..... 16

7 oc triangle yellow, tergites yellow dorsally, brown on lateral margins, 0+3 dc; ep with small oval spot in middle (as in maraisi, see Fig. 12); ♂ postabdomen, Fig. 25 ................................................................................................ stuckenbergi sp. n.

– oc triangle black or at least ocelli ringed with black, tergites darker dorsally than laterally or entirely yellow, 0+2 dc ....................................................................... 8

8 Epandrium, viewed from behind, with a distinct midline brown spot ................. 9

– Epandrium uniformly yellow.............................................................................. 13

9 Epandrial spot large, more or less rhomboidal and almost reaches anterior border of ep (Fig. 2a), oc triangle yellow, ocelli ringed with black; ♂ postabdomen, Fig. 8 .............................................................................................................. gilva sp. n.

– Epandrial spot smaller, occupying less than 1/3 width or height of ep when viewed from behind ......................................................................................................... 10

10 Prescutellar acrs distinct but short, epandrial spot broader, more pentagonal in shape with large central part clearly shining and well separated from edge of ep above cerci (Fig. 2e); ♂ postabdomen, Fig. 9 ................................... maculiventris sp. n.

– Prescutellar acrs setae well-developed; epandrial spot narrow oval or rectangular, not or very little shining and lower edge touching the margin of ep above the cerci (Figs 2a, c, d, e) .................................................................................................. 11

11 acrs in 8–10 irregular rows at level of transverse suture, epandrial spot small, more or less triangular and touching posterior margin of ep above cerci; ♂ postabdomen, Fig. 23 .............................................................................................. setulosa sp. n.

– acrs in 6–8 irregular rows at level of transverse suture, epandrial spot either rectangular or well separated from edge of ep above cerci (Figs 2b, f) ............. 12

12 Epandrial spot small, oval and situated at middle third (Fig. 2b), apex of distiphallus large and broadly globular; ♂ postabdomen, Fig. 12 ...................... maraisi sp. n.

– Epandrial spot narrow, rectangular and situated at posterior third just above cerci (Fig. 2f), apex of distiphallus narrow and more or less pointed; ♂ postabdomen, Fig. 21 .......................................................................................... punctata Ebejer

13 oc triangle dark, 0+1 dc, acrs in 6–8 rows, tergites long setulose; ♂ postabdomen, Fig. 20 ........................................................................................ pretoriella sp. n.

– Not with all these character states combined...................................................... 14

14 Head large and broader than thorax (Fig. 15) with very deeply recessed gena, usually 0+3 dc, acrs posteriorly often markedly reduced in number to one or two pairs; ♂ postabdomen, Fig. 14 .............................................................. megacephala sp. n.

– Head normal, 0+2 dc, acrs posteriorly usually more numerous, at least 3–4 pairs ............................................................................................................................ 15

15 Frons broad, at level of antennae about 1.2 width of one eye; ♂ postabdomen, Fig. 11 ........................................................................................ malagasica sp. n.

– Frons narrower, at level of antenna about 0.8 width of one eye; ♂ postabdomen, Fig. 24 ............................................................................................ spinifera sp. n.

16 Apical tergites with well-defined dark spots ...................................................... 17

– Apical tergites without discrete dark spots ......................................................... 19

17 Tergites subshining, each becoming darker at middle third where more discrete brown spots appear, which in turn become darker towards apex of abdomen, sometimes a short brown stripe is present along dc line posteriorly, sometimes metanotum more brownish than yellow, abdominal setulae long pale brown to black: on dorsal aspect of tergites at least 2/3 length of tg; ♀postabdomen, Fig. 10 ....... ............................................................................................... maculiventris sp. n.

– Tergites matt, usually only tg 7 with small, brown, more or less quadrate spot at middle third; setulae on dorsal part of tergites short; most only 1/3 length of tg ............................................................................................................................ 18

18 Only tg 7 with small, brown, more or less quadrate spot at middle third; caudal end of plates of st 8 rounded and without any extension; ♀postabdomen, Fig. 13 ...... ......................................................................................................... maraisi sp. n.

– Either tg 7 with small, pale brown, more or less quadrate spot at middle third, or all tergites darkened at middle; caudal end of plates of st 8 with broad triangular extension; ♀postabdomen, Fig. 22 ............................................. punctata Ebejer

19 oc triangle dark, 0+1 dc, tergites with brown setulae ................. pretoriella sp. n.

– oc triangle yellow, 0+2 dc, tergites with brown or yellow setulae ..................... 20

20 Head large and broader than thorax, with deep and recessed gena; acrs sparse in 4– 6 rows, tergites yellow with pale setulae; ♀postabdomen, Fig. 16 ....................... ................................................................................................ megacephala sp. n.

– Head at most as broad as thorax and gena not recessed or exceptionally deep, acrs numerous in 6–8 rows ......................................................................................... 21

21 Tergites yellow with pale yellow setulae, which laterally are about 3/4 length of tg ......................................................................................................... setulosa sp. n.

– Tergites pale brownish yellow with dark brown setulae, which laterally are about only half length of tg ..................................................................... spinifera sp. n.