The adult Robber Fly is a predator of other flying insects. They attack a variety of insects, even those that are larger than themselves.
They insert their short but strong proboscis into the insects to suck their body fluids. Some larger species can give a painful bite if handled.
Adults are common in dry, open, and sunny places. The larvae can be found in the soil, decaying wood, or fallen leaves.
Robber flies are small to very large-sized, hairy with usually a long slender abdomen. The legs are long and spiny. The lower part of the face or sometimes the entire face is covered with dense bristles, and the top of the head is excavated. Most are dark-coloured, but some are black and yellow and look like bees.
The astounding success of flies is owing to their great versatility in the exploitation of habitats and their ability to utilize every possible sort of food. Flies are ubiquitous and are abundant in individuals as well as in species numbers. They are an important food source for other animals. Many are parasitic on other insects and help keep their populations under control.
Some herbivorous flies have been successfully used to control weeds. Many are important pollinators of plants. Many are invaluable as scavengers and are vital in aiding the decomposition of plant and animal material. They are the insects most known to infect humans and domesticated animals with deadly diseases. Bloodsucking flies transmit many diseases, including malaria, yellow fever, and sleeping sickness.
True Flies are always listed as 2 words separated like crane fly while others are listed as 1 word like dragonfly or damselfly. The compound eyes are usually large, often occupying most of the head.