Promachus bastardii, commonly known as the Bastard Robberfly, is a large predatory insect belonging to the family Asilidae. It is characterized by its robust body, long legs, and a distinct proboscis used for piercing and sucking fluids from its prey. Found in various habitats across North America, this formidable predator feeds on a wide range of insects, including bees, wasps, and other flies.