Key to the species and subspecies of the genus Trechosiella

1 Temporal lobe well developed, smooth; species from southern Africa........................................... 2

- Temporal lobe weakly developed, rugose; species from Tanzania .............................. T. basilewskyi Jeannel

2 Eyes not protruding, eye diameter smaller than length of temple................................................ 3

- Eyes protruding, eye diameter larger than length of temple.................................................... 4

3 Elytral striae on disc effaced; temple longer than half diameter of eye; microsculpture of elytra strongly transverse, length/ width ratio of mesh approximately 1:5 to 1:10......................................... T. oligophthalma spec. nov.

- Elytral striae on disc well discernable;eye diameter subequal to temple length; microsculpture of elytra weakly transverse, length/width ratio of mesh approximately 1:1 to 1:2............................. T. scotti swartbergensis subspec. nov.

4 Third elytral stria with two setiferous punctures, one at the level of the anterior quarter, the other posterior of the middle of the elytral disc; 3rd and 4th striae distinctly separate in anterior quarter of elytral disc.................................. 5

- Third elytral stria lacking posterior setiferous puncture; 3rd and 4th striae converging in anterior quarter of elytral disc.................................................................................... T. endroedyyoungai spec. nov.

5 Microsculpture of elytra strongly transverse, length/width ratio of mesh approximately 1:5 to 1:10; apex of aedeagus tapered (lateral view)........................................................................................ 6

- Microsculpture of elytra less transverse, length/width ratio of mesh approximately 1:2 to 1:3; apex of aedeagus blunt...... 7

6 Apex of aedeagus bended bent ventrad, internal sac with multiple tightly packed, minute sclerotized teeth.................................................................................................... T. laetula (Pringuey)

- Apex of aedeagus straight, internal sac without any internal sclerotized teeth or pieces microstructures........................................................................................................ T. katicola Jeannel

7 Brachypterous..................................................................... T. scotti scotti (Jeannel)

- Macropterous, only known from Namibia .................................... T. scotti macroptera Casale, stat. dem.