Nepomorpha

Notonectidae is a cosmopolitan family of aquatic insects in the order Hemiptera, commonly called backswimmers because they swim "upside down" (inverted). They are all predators and typically range from in length. They are similar in appearance to Corixidae (water boatmen), but can be separated by differences in their dorsal-ventral coloration, front legs, and predatory behavior. Their dorsum is convex, lightly colored without cross striations. Their front tarsi are not scoop-shaped and their hind legs are fringed for swimming. There are about 350 species in two subfamilies: Notonectinae with s

Corixidae is a family of aquatic insects in the order Hemiptera. They are found worldwide in virtually any freshwater habitat and a few species live in saline water. There are about 500 known species worldwide, in 55 genera, including the genus Sigara.

Belostomatidae is a family of freshwater hemipteran insects known as giant water bugs or colloquially as toe-biters, Indian toe-biters, electric-light bugs (because they fly to lights in large numbers), alligator ticks, or alligator fleas (in Florida). They are the largest insects in the order Hemiptera. There are about 170 species found in freshwater habitats worldwide, with more than 110 in the Neotropics, more than 20 in Africa, almost as many in the Nearctic, and far fewer elsewhere. These predators are typically encountered in freshwater ponds, marshes and slow-flowing streams. Most speci

Pleidae, the pygmy backswimmers, is a family of aquatic insects in the order Hemiptera (infraorder Nepomorpha, or "true water bugs"). There are 52 species in four genera, distributed across most of the world, except the polar regions and remote oceanic islands.

Nepomorpha is an infraorder of insects in the "true bug" order (Hemiptera). They belong to the "typical" bugs of the suborder Heteroptera. Due to their aquatic habits, these animals are known as true water bugs. They occur all over the world outside the polar regions, with about 2,000 species altogether. The Nepomorpha can be distinguished from related Heteroptera by their missing or vestigial ocelli. Also, as referred to by the obsolete name Cryptocerata ("the hidden-horned ones"), their antennae are reduced, with weak muscles, and usually carried tucked against the head.

thumb|Pelocoris femoratus Naucoridae is a small family of insects commonly known as the creeping water bugs and saucer bugs. They are similar in appearance and behavior to Belostomatidae (giant water bugs), but considerably smaller, at long. Naucoridae are found around the world, but the greatest diversity is in tropical regions. They inhabit a wide range of freshwater habitats, ranging from still waters like ponds, to flowing rivers and even torrential streams. There are eight subfamilies containing about 400 species in 46 genera. One of these subfamilies is Pelocoris, and the species within

The Gelastocoridae (toad bugs) is a family of about 100 species of insects in the suborder Heteroptera. These fall into two genera, about 15 species of Gelastocoris from the New World and 85 of Nerthra from the Old World. They are reminiscent of toads both in the warty appearance and hopping movements of some species.

thumb|Ochterus marginatus

Helotrephidae is a family of aquatic bugs found mainly in the tropical regions with many species in the Oriental Realm and a few from Africa, Madagascar and South America. These bugs are found swimming or walking amid submerged vegetation in stagnant or slow moving, shaded freshwater in forest habitats. They are a sister group of the Pleidae.

Potamocoridae is a family of true water bugs. The family was first scientifically described by Robert L. Usinger in 1941.