Assassin bug is a generic term for true bugs that use a long proboscis to stab prey, dissolve the juicy bits, and drain the liquefied remains. Horrific, no?
Of course, there's a bit of irony about an insect that is no larger than your pinky fingernail being called an assassin. But given the patient, predatory nature of these bugs, and their size in comparison to their victims, assassin is accurate.