Megalopinus is immediately recognizable by its distinct habitus, bulging eyes occupying most of the lateral head margin, orange elytral markings, and clubbed antennae (Fig.1.8.1). They are somewhat similar to Steninae but with antennae inserted in front of a line drawn at the anterior margin of the eyes (Fig.1.8.1).

These beetles appear to be microhabitat specialists, living under dead logs with fungal growth (Leschen and Newton 2003). As they feign death and drop to the ground after disturbance (Leschen and Newton 2003), they are probably best collected by sifting fungusy debris under logs. Specimens have also been collected from pan traps near forest and hand-collected from fungus.             Two species of this mostly tropical genus occur in the southeastern and south-central United States and reach their known northern limit in Indiana. However, they are very rarely encountered and they may eventually be found elsewhere in ECAS.

Individuals of Megalopinus caelatus Gravenhorst have been observed feeding on larval Diptera in the laboratory, slowly locating and capturing their prey during the day (Leschen and Newton 2003). They likely hunt invertebrates associated with fungus growing on the undersides of logs.