A new high altitude montane species of Trichostetha Burmeister, 1842 is described from the Elandsberg range of the Western Cape interior. This represents the 14th species of the genus and the first to be reported with a description of its larva.
It is a significant addition to the growing number of species that exhibit no adult feeding behaviour and a short period of activity restricted to the onset of summer. Larvae dwell in rock crevices, feeding on decomposing plant matter.
The genus Trichostetha is heterogeneous and the complex variability observed in some species, especially T. capensis (Linnaeus, 1767), requires the re-instatement of taxa that were recently synonymised. Thus, T. bicolor Peringuey, 1907 is here re-proposed as a separate species and T. capensis hottentotta (Gory & Percheron, 1833) as a separate subspecies.
Conversely, T. alutacea Allard, 1994 is recognised as a dark variety of T. signata (Fabricius, 1775) and is, consequently, synonymised with this species.