Key to males of Silba admirabilis species group

(all Afrotropical unless indicated)

1. Phallus boat-shaped, basal plate fused laterally to phallus, basiphallus spiculate (Figs. 33–34)....................................................................................................... chalkei McAlpine; S.E. Asia.

- Phallus with a distinct ventrally situated basal plate.......................................................... 2

2. Phallus with an additional pair of processes between it and the basal plate (Figs. 29–30)................................................................................................. admirabilis McAlpine; India & Sri Lanka.

- Phallus without such additional processes.................................................................. 3

3. Basiphallus with an obvious bulge on inner surface, in anterior view basal plate of phallus simple and lanceolate. (Figs. 35–36)......................................................................... flavitarsis MacGowan; S.E. Asia.

- Basiphallus without such a bulge or lanceolate basal plate..................................................... 4

4. In ventral view basal plate of phallus diamond shaped (Figs. 16 & 18)............................................ 5

- In ventral view basal plate of phallus not diamond shaped...................................................... 6

5. Basal plate serrated apically and laterally, apical excavation a narrow V-shape (Figs. 15–16)................................................................................................................ lubumbashi sp. nov.

- Basal plate without marginal serrations, apical excavation broader, U-shaped (Figs. 17–18)................ mbuti sp. nov.

6. In ventral view basal plate of phallus with apical margin only slightly concave, without a large V or U-shaped excavation (Figs. 8, 26, 38 &42).................................................................................. 7

- Basal plate of phallus at apex with an obvious V or U-shaped excavation........................................ 10

7. Basal plate long and very narrow, without any marginal serrations or spicules. (Fig. 8)................... bredoi sp. nov.

- Basal plate wider, often with marginal serrations or spicules. (Figs. 26, 38 &42).................................. 8

8. Basal plate shorter than phallus, thin and translucent, with serrated margins, basiphallus broad and setulose (Figs. 37 & 38)................................................................................. hilli (Malloch); Australasia

- Basal plate as long or longer than phallus. (Figs. 26 –42)...................................................... 9

9. Apical margin of basal plate strongly serrated (Fig. 26).......................................... upemba sp. nov.

- Apical margin of basal plate almost smooth, with only a few spicules (Fig. 42).................... namibia MacGowan

10. In ventral view basal plate of phallus markedly swollen medially, apex with two diverging processes with between them an open U-shaped excavation (Fig 24)............................................................. tekei sp. nov.

- In ventral view basal plate of phallus not markedly swollen medially........................................... 11

11. Basal plate of phallus bearing spicules across its ventral surface (Figs 22 & 32)................................... 12

- Basal plate of phallus without spicules across its ventral surface................................................ 13

12. Basal plate covered in large spicules, apically with a large open V-shaped excavation (Figs. 31–32).... apodesma McAlpine

- Basal plate bearing only small spicules, mostly along margins, apically with a U-shaped excavation (Figs 21–22)................................................................................................ spiculata sp. nov.

13. In ventral view basal plate of phallus narrow, with a spanner-shaped apex (Figs. 9–10)................. garamba sp. nov.

- In ventral view basal plate of phallus usually broader, without such a spanner-shaped apex.......................... 14

14. In ventral view basal plate of phallus apically split for almost half of its length (Figs. 20 & 28)...................... 15

- In ventral view basal plate of phallus without such a deep split............................................... 16

15. Basal plate of phallus with two thin leaf-like parallel, gradually tapering, bluntly pointed apical lobes (Figs. 27–28)................................................................................................. wittei sp. nov.

- Basal plate of phallus with parallel apical lobes constricted near apex, in lateral view with expanded apex. (Figs. 19–20)............................................................................................ saegeri sp. nov.

16. In ventral view basal plate of phallus with two square-ended apical processes separated by a V-shaped excavation. (Figs. 39– 40).................................................................. israel MacGowan and Freidberg; Israel .

- Basal plate of phallus without square ended apical processes.................................................. 17

17. In lateral view basiphallus very broad and rounded (Fig. 11). In ventral view basal plate widening at apex, forming two rather narrow, lateral apical processes separated by a wide apical excavation (Fig. 12)....................... hambai sp. nov.

- In lateral view basiphallus not greatly broadened (Figs. 3, 5, 13 & 43).......................................... 18

18. In ventral view basal plate widening steadily from base to apex, apical processes almost parallel sided, apical excavation a rel- atively wide U-shape (Figs. 3–4)............................................................ bakongo sp. nov.

- In ventral view basal plate broadest before the apex or straight sided (Figs. 6, 14 & 44)............................ 19

19. In ventral view basal plate parallel sided, apex with two pointed processes divided by a U-shaped excavation (Figs. 43–44)................................................................................... pappi Soós; Afghanistan

- In ventral view basal plate not parallel sided, broadest before the apex (Figs. 6 & 14).............................. 20

20. Basal plate broadened apically, in ventral view widest at apical third, apical processes slightly bulbous at apex, apical excavation a narrow mouthed U-shape, basiphallus not swollen. (Figs. 5–6)................................ boulangi sp. nov.

- Basal plate thin and translucent, in ventral view at apical quarter before narrowing to apex with a V-shaped apical excavation, in ventral view basiphallus slightly swollen (Figs. 13–14)......................................... inimvua sp. nov.