Key to African species in subgenus Parena Motschulsky

1. Postgenae with a pair of long suborbital setae (12. P. stigmatica group)........................................... 2

- Postgenae without suborbital setae........................................................................ 4

2. Dorsum dark brown; antennae reddish brown, apical antennomeres of similar color to basal ones; elytra with deep and wide depressions on anterior third of intervals 3–6, another small depression present on the base of interval 6; Madagascar ................................................................................... [37] P. stigmatica (Fairmaire)

- Dorsum yellowish brown; basal three or four antennomeres yellow, remaining antennomeres much darker; elytra without or with very shallow depressions on anterior third of intervals 3–6; African mainland.................................. 3

3. Antennomere 4 entirely yellow; lateral margins of pronotum strongly sinuate before posterior angles; elytra disc slightly darker than lateral areas; elytral striae clearly incised, finely punctate inside; interval with dense fine punctures; Angola ......................................................................................... [38] P. doriae Basilewsky

- Antennomere 4 with yellow basal half and dark apical half; lateral margins of pronotum almost straight before posterior angles; elytra evenly yellowish brown; elytral striae faintly incised, formed by rows of punctures; interval with very sparse fine punctures; Tanzania, Zimbabwe ................................................................ [39] P. fulva sp. n.

4. Elytral apices truncate, apical margin nearly straight, sutural angles more or less pointed, forming short spines or denticles, although very faint in some species (Figs 5B, 5C, 5D); elytra without microsculpture (except in P. madagascariensis); antennomere 1 with the ventroapical seta much more than half length of the dorsal-apical one (Fig. 1D); LL greater than LW (13. P. scutata group)........................................................................................ 5

- Elytral apices subtruncate, apical margin evenly curved, sutural angles not pointed (Fig. 5A); elytra with shallow isodiametric microsculpture; antennomere 1 with the ventroapical seta less than half length of the dorsal-apical one (Fig. 1C); LL less than LW (14. P. plagiata group).............................................................................. 8

5. Elytra brown, or brown with very narrow black lateral stripes.................................................. 6

- Elytra largely black, reddish brown near apices.............................................................. 7

6. Elytra reddish brown; elytral apices very strongly truncate, outer apical angles prominent (Fig. 5D); Madagascar ................................................................................. [40] P. madagascariensis (Alluaud)

- Elytra with black lateral stripes from humeri to middle; elytral apices moderately truncate, outer apical angles rounded (Fig. 5C); Zambia ...................................................................... [41] P. valeriae Facchini

7. Elytral disc with well-defined reddish brown patch inside black area, extended over medial four or five intervals at middle; antennomeres 5–11 black, distinctly darker than basal antennomeres.......................... [42] P. scutata (Alluaud)

- Elytra disc black except for paler apices, without a central paler patch; antennae uniformly reddish brown................................................................................................. [43] P. ruficornis sp. n.

8. Elytra entirely brown.................................................................................. 9

- Elytra largely black, reddish brown near apices............................................................. 10

9. Elytra striae very shallow, completely smooth on posterior half; lateral margins of pronotum slightly sinuate before posterior angles; tarsi dark brown, much darker than tibiae..................................... [44] P. ferruginea (Chaudoir)

- Elytra striae slightly deeper, shallowly incised even on posterior half; lateral margins of pronotum strongly sinuate before posterior angles; tarsi yellow, same color as tibiae................................ [46] P. africana (Alluaud) (pale form)

10. Apical red band of elytra very narrow, length less than 1/20 of elytra length; inner intervals slightly reddish, forming vague central patch; elytra discal depressions elongate; lateral margins of pronotum less sinuate before posterior angles; median lobe of aedeagus stouter, AL/AW about 4.0; South Africa .................................... [45] P. plagiata Motschulsky

- Apical red band of elytra wider, length about 1/10 of elytra length; inner intervals black, without central patch; elytral discal depressions sub-triangular; lateral margins of pronotum strongly sinuate before posterior angles; median lobe of aedeagus slenderer, AL/AW more than 4.5.............................................. [46] P. africana (Alluaud) (dark form)