What is "dytiscus"

Dytiscus (great diver) (based on Greek δυτικός, "able to dive") is a Holarctic genus of predaceous diving beetles that usually live in wetlands and ponds. There are 26 species in this genus distributed in Europe, Asia, North Africa and North and Central America. They are predators that can reduce mosquito larvae.

Dytiscus species are large water beetles with a robust, rounded shape and are usually around two inches long. The tarsi of the males are modified into suckers which are used to grip the female in mating. Females are usually larger than the males and come in two forms, with grooved (sulcate) or smooth elytra. Males only ever have smooth elytra. The adults of most species can fly.