Lethocerus is a genus of the hemipteran family Belostomatidae, known colloquially as giant water bugs, distributed in tropical, subtropical and temperate areas of the world. The greatest diversity of species occurs in the Americas, with only a single species in Europe, two in Africa, two in Australia and three in Asia. It includes the largest true bugs with species capable of reaching a length of over. The South American L. grandis and L. maximus are the only species to commonly exceed, with more typical lengths for the remaining species being between. Lethocerus sp. are distinguished from other genera in the Lethocerinae by two symmetrical furrows in the inner pad of setae on the fore femur, the external borders of parasternites II and III narrowed and nearly straight, and with the setae of the tarsomeres following the line of the tibial setae.
Habits
Unlike giant water bugs in the subfamily Belostomatinae, females do not lay the eggs on the backs of males. Instead, after copulation the eggs are laid on emergent vegetation high enough above the waterline that the eggs will not be permanently submerged. The male then guards the eggs from predators and periodically brings water to the eggs to prevent their desiccation. Like other members of the giant water bug family, Lethocerus species are predators that overpower prey by stabbing it with the rostrum and injecting a venomous saliva. The rostrum can also be used in self-defense, and the bite is very painful to humans, but usually resolves within a few hours at most.
Species
, this is an exhaustive listing of all known species of Lethocerus:
Lethocerus americanus
Lethocerus angustipe
Lethocerus annulipes
Lethocerus bruchi
Lethocerus camposi
Lethocerus collosicus
Lethocerus cordofanus
Lethocerus delpontei
Lethocerus dilatus
Lethocerus distinctifemur
Lethocerus grandis
Lethocerus indicus
Lethocerus insulanus
Lethocerus jimenezasuai
Lethocerus maximus
Lethocerus mazzai
Lethocerus medius
Lethocerus melloleitaoi
Lethocerus oculatus
Lethocerus patruelis
Lethocerus truxali
Lethocerus uhleri
In addition to these, Lethocerus deyrollei, which is one of the best known giant water bugs, has traditionally been included in this genus, but in 2006 it was moved to Kirkaldyia.