Onymacris rugatipennis, a tenebrionid from the Namib Desert, is currently classified as having two subspecies distinguishable in the adult phase (Penrith, 1975). However, other authors have suggested species status for the 'waxy' and 'non-waxy' types on the basis of larval characteristics and the apparent lack of introgression of adult morphology in areas of overlap (Koch, 1962; Schulze, 1962, 1964; Osberg, Hanrahan & Seely, 1986). In a previous paper (Hauffe & Seely, In press) we took the view that waxiness in O. rugatipennis is a continuously varying character that does not define major taxonomic subdivisions. Behavioural observations reported here support this idea; daily activity patterns and precopulatory behaviour of waxy and non-waxy adult O. rugatipennis is very similar under the same environmental conditions. In addition, allozyme analysis indicates that there is little genetic divergence between populations across the range of this species.