Final answer:
The robber or assassin fly can be described as a Hoverfly, known for its predatory behavior and agile flight.
Step-by-step explanation:
The robber or assassin fly can be described as a type of Hoverfly. The Latin word for "Pillager" refers to their predatory behavior of capturing and preying on other insects. The robber or assassin fly is known for its agile flight and ability to catch and immobilize its prey in mid-air. Although it looks similar to a housefly or a dragonfly, it belongs to the family Syrphidae, which includes hoverflies.