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.
Hercules beetle
The Hercules beetle ("Dynastes hercules", Dynastinae) is a species of rhinoceros beetle native to the rainforests of Central America, South America, and the Lesser Antilles, and is the longest extant species of beetle in the world, and is also one of the largest flying insects in the world.