Mosquito
Mosquitoes of the genus "Toxorhynchites" never drink blood. This genus includes the largest extant mosquitoes, the larvae of which prey on the larvae of other mosquitoes. These mosquito eaters have been used in the past as mosquito control agents, with varying success.
Cockroach
Most species of cockroach are about the size of a thumbnail, but several species are bigger. The world's heaviest cockroach is the Australian giant burrowing cockroach "Macropanesthia rhinoceros", which can reach in length and weigh more than . Comparable in size is the Central American giant cockroach "Blaberus giganteus", which grows to a similar length. The longest cockroach species is "Megaloblatta longipennis", which can reach in length and across. A Central and South American species, "Megaloblatta blaberoides", has the largest wingspan of up to .