Key to species groups and subgroups of the genus Pseudotetracha Fleutiaux, 1894
(modified from Sumlin 1997)
1 Elytra unicolorous or with a testaceous apex only (subg. Pseudotetracha s. str.).................................... 2
- Elytra with a testaceous margin extending from shoulder to apex (subg. Australicapitona Sumlin, 1992)............... 11
2 Abdominal segments 3–6 with numerous small, clear setae; unicolorous or with a very thin apical testaceous area (“ black- burni” group)........................................................................ “ pulchra ” subgroup
- Abdominal segments without very small, clear setae.......................................................... 3
3 Elytra unicolorous, without a testaceous apex.............................................................. 7
- Elytra with a testaceous apex (“ australis ” group)............................................................ 4
4 Testaceous apex large, nearly covering apical third of elytra; lateral carina of pronotum present to at least posterior half.................................................................................. P. australis (Chaudoir, 1865)
- Testaceous apex not covering apical third of elytra........................................................... 5
5 Lateral carina of pronotum reaching nearly to the posterior dorsal sulcus; elytra moderately ovate and punctate in basal half................................................................................. P. whelani (Sumlin, 1992)
- Lateral carina of pronotum present on anterior fourth to anterior two thirds, not reaching nearly to the posterior dorsal sulcus.................................................................................................... 6
6 Elytral ground color purple, violet or bluish-purple, elytra nearly parallel-sided elytral length to width ratio> 1.5. Some speci- mens of P. kimberleyensis (Mjöberg, 1916) may have dark green elytra........................... “ spenceri ” subgroup
- Elytral ground color green, blue, blue-green or cupreous, elytra more ovoid........................ “ helmsi ” subgroup
7 Antennomeres 1–4 and femora with at least terminal ends brown or black; elytra elongate oval with humeri rounded, punctate, with deep subsutural foveae in basal third................................................. “ marginicollis ” group
- Antennomeres and femora unicolorous, yellow without darkish terminal ends; elytra not very ovate, more-or-less parallel- sided, with distinct humeri............................................................................. 8
8 Elytra rectangular, apices truncated, squared. Elytra purple or purplish blue. Lateral carina of pronotum extending to midlength................................................................................ P. greyana (Sloane, 1906)
- Elytra not rectangular.................................................................................. 9
9 Lateral carina of pronotum extending past midlength (“ blackburni ” group)...................................... 10
- Lateral carina absent or present only in anterior fourth......................................... “ cylindrica ” group
10 Elytra punctate to apex. Lateral carina of pronotum extending at least to posterior dorsal sulcus.................................................................................................... P. blackburni (Fleutiaux, 1895)
- Elytra not punctate to apex. Lateral carina of pronotum reaching near posterior dorsal sulcus....... “ murchisona ” subgroup
11 Elytral margins microserrate at least near apex.............................................. “ australasiae ” group
- Elytral margins smooth.................................................................. “ crucigera ” group