Broadly oval, 5·8 × 3·9 mm., slightly broader at the posterior third; rounded in front, the posterior border more flattened. Integument mammillate and with dorsal depressions and discs, and ventral grooves strongly recalling O. coriaceus (see Fig. 1). Numerous short white hairs scattered over the integument, and notably a ring of close-set clavate hairs round the base of each trochanter. Eyes absent. The half-gorged ♂ measures 6 × 4 mm.