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.
Giant burrowing cockroach
The giant burrowing cockroach ("Macropanesthia rhinoceros") is also known as the rhinoceros cockroach and litter bug. These cockroaches are native to Australia and mostly found in tropical parts of Queensland. They are the world's heaviest species of cockroach and can weigh up to and measure up to in length. They can live for up to 10 years. Unlike some other cockroaches, they do not have wings and are not considered pests. The cockroach plays a vital part in the ecosystem by consuming dead leaves, eucalyptus in particular, and recycling other matter. True to their name, they may burrow down in soil to a depth of about , where they make permanent homes. Adult males and females can be differentiated by the size of the "scoop" on the pronotum, which covers the head; the male having a much more pronounced scoop. They grow by shedding their outer shells 12 or 13 times before reaching full size. When a cockroach moults, it will appear pure white except for the eyes. The species is ovoviviparous.