**Description:** Oval, black beetles that spin in rapid, dizzying circles on the surface of calm water pools.
**Size:** 0.4 to 0.6 inches long.
**Behavior:** Eyes are divided into two halves to see above and below the water simultaneously. They secrete a foul-smelling liquid to deter fish.
**Identification:** Almost always seen in large, social groups. They are incredibly fast and can dive underwater instantly if disturbed.
**Habitat:** Sheltered reservoir coves and quiet eddies of forest streams.