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.
Wuchereria bancrofti
The microfilariae are transferred into a vector, which are most commonly mosquito species of the genera "Culex", "Anopheles", "Mansonia", and "Aedes". Inside the mosquito, the microfilariae mature into motile larvae called juveniles; these migrate to the labium after a period around 10 days. When the infected mosquito has its next blood meal, "W. bancrofti" larvae are deposited from the mouthparts onto the skin of the prospective host and migrate through microcuts in the dermis or the tract created by the proboscis into the blood stream of the new human host. The larvae move through the lymphatic system to regional lymph nodes, predominantly in the legs and genital area. The larvae develop into adult worms over the course of a year, and reach sexual maturity in the afferent lymphatic vessels. After mating, the adult female worm can produce thousands of microfilariae that migrate into the bloodstream. A mosquito vector can bite the infected human host, ingest the microfilariae, and thus repeat the lifecycle. The organism notably does not multiply within its intermediate host, the mosquito.