This small white to buff species (to 4mm) has eyes composed of a single black ocellus. As with all trichoniscid woodlice the antennal fagellum comprises a tapered cone (of indistinct segments) bearing a terminal bristle. The longitudinal dorsal ridges, which are characteristic of the genus, are much less distinct than seen in H.mengii and H.montivagus, and it also lacks the pair of prominent projections on the third pleonite that is characteristic of those two species. Characteristically, Haplophthalmus species have a continuous body outline (all other trichoniscid woodlice have a stepped body outline).
The male has a characteristic upwardly directed spur on the carpus of the 7th leg.
Distribution and Habitat
Although common in many south-eastern areas, it becomes increasingly rare further north.
It is often associated damp well-vegetated habitats, such as damp woodland, farmyards, churchyards and gardens, where it typically inhabits damp rotten wood, peaty debris and compost heaps.
This summary is based on the detailed account in Gregory (2009).