Carabidae (ground beetles, including paussids, rhysodids and cicindelids) 

A large family with about 289 genera and 1638 species in southern Africa. Species are predominantly ground-dwelling predators but there are some exceptions such as the paussid beetles that live in ant nests and eat ant larvae.

Rhysodidae

Gyrinidae (whirligig beetles)

These are the beetles one sees darting round on the water surface at high speed, often in groups. They dive readily when disturbed and use air trapped beneath the elytra for respiration. The family is distinguished from other beetles in having the compound eyes divided into two: a dorsal pair for seeing into the air and a ventral pair for seeing under water. Adults feed mainly on insects on the water surface but there are species that feed on aquatic vegetation. There are four genera and about 45 species of gyrinids in southern Africa. 

Haliplidae (crawling water beetles)

Small aquatic beeltes (2.4 - 4.5 mm long) that crawl around on submerged vegetation feeding on algae. There are three genera and 10 species in southern Africa. Larvae are also aquatic and live among algae and other submerged vegetation. 

Aspidytidae (cliff water beetles)

Dytiscidae (water beetles)

Aquatic predatory beetles, ranging widely in size (1 - 45 mm long). Adults and larvae feed mainly on aquatic insects and crustaceans. They are able to remain under water for fairly long periods by keeping a supply of air in the subelytral cavity (i.e. beneath the elytra).  However occasional replenishment of the air supply is needed. There are about 40 genera and 250 species of dytiscids in southern Africa.