This powerful hunter-killer of the insect world is superbly designed. The robber fly will have sat it wait, using its high resolution forward facing eyes and flexible neck to scan for a reasonably large insect to fly nearby. It then rapidly takes off, launching into the attack, grasping the prey in flight with its strong spiny legs. In flight or on landing, its piercing mouth parts inject poisonous saliva into its prey, immediately incapacitating it.