Key to the males of Umbothynnus

1 Lateral carinae on T7 straight and slightly convergent then abruptly incurved, convergent and almost confluent but strongly curved and directed posteriorly (fig. 10); pronotum sparsely punctate ................. .................................................................................................................................. subspinosus, sp. nov.

- Lateral carinae on T7 otherwise, not strongly convergent and almost confluent posteriorly, not curved and directed posteriorly (figs 4–9, 11); pronotum punctate to rugose-punctate.......................................2

2(1) Clypeus strongly and broadly carinate, carina produced and tuberculate over apical margin of clypeus. .................................................................................................................................. subcornutus, sp. nov.

- Clypeal carina not produced over apical margin of clypeus, and not tuberculate .................................. 3

3(2) T7 subapically carinate; lateral margins of parameres strongly convergent posteriorly (fig. 7) ............... ..................................................................................................................................... infuscatus, sp. nov.

- T7 not subapically carinate; lateral margins of parameres not strongly convergent posteriorly ............ 4

4(3) Clypeus truncate or weakly emarginate .................................................................................................. 5

- Clypeus narrowly and strongly emarginate ............................................................................................. 6

5(4) T7 not raised and angulate posterolaterally (fig. 8); basiparameres each rounded apically (fig. 29) ........ ................................................................................................................................ katherinensis, sp. nov.

- T7 raised and angulate posterolaterally (fig. 11); basiparameres acute apically (fig. 38) ......................... .................................................................................................................................... webbiensis, sp. nov.

6(4) Posterior angles of T7 flat, not upturned (fig. 4); apices of basiparameres digitate (fig. 14) .................... .......................................................................................................................................... alexius (Turner)

- Posterior angles of T7 upturned forming a concave area (figs 5–6); apices of basiparameres broad or incurved, not digitate (figs 20, 23) ......................................................................................................... 7

7(6) Apex of T7 (as defined by its concavity) wider than long, posterior angles not spinose (fig. 5); apices of basiparameres incurved (fig. 20) ......................................................................... bertholetiensis, sp. nov.

- Apex of T7 longer than wide, posterior angles obtusely spinose (fig. 6); apices of basiparameres not incurved (fig. 23) .............................................................................................. borrolooliensis, sp. nov.