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.
Hystrichopsylla schefferi
Hystrichopsylla schefferi, also known as the mountain beaver flea and giant mountain beaver flea, is a parasitic holarctic insect belonging to the order Siphonaptera, the "siphon-wingless" (fleas). The fully grown adult can measure as much as in length, and it is the largest living flea in the world. It is native to the American Northwest. Though most members of the genus "Hystrichopsylla" are not strongly associated with any particular host animal and will generally parasitize insectivores and rodents, "H. schefferi" is monoxenously associated with the mountain beaver with which its range is coterminous. The fleas of the family Hystrichopsyllidae, along with the family Pulicidae, are the oldest of fleas in evolutionary history. "H. schefferi" can be distinguished from the very similar and closely related species "Hystrichopsylla gigas dippiei" by the number of spines in the pronotal comb, as "H. g. dippiei" has 36 and "H. schefferi" has 46.