ROBBER FLY

also called Assassin Fly, any predatory insect of the family Asilidae (order Diptera), numbering about 4,000 species, worldwide in distribution. These flies have variable lengths that range to almost 8 cm (3 inches). They are the largest of all flies. Most are dull in colour, and their stout bodies resemble those of bumble bees. Between the large-faceted eyes is a moustache of bristles. The long legs are adapted to capture prey in flight and to hold it while eating. The robber fly, a predator of almost all flying insects, injects a fluid into its victims that breaks down the muscle tissue. A few species of the genus Promachus are serious pests of apiaries because they feed on bees. Each species has a characteristic habitate.g., tree trunk, foliage, grass, low plant, dead twig, gravel, or beach sand.