There are over 7,000 different species of Robber Flies around the world. They are all are great hunters and prey on many different insects including butterflies, bees, dragonflies, wasps, bees and other flies. They are able to hold their prey with their front legs and then inject saliva into the victim which causes paralysis after which the Robber Fly feeds on the insect by sucking out its body fluids. They are usually covered with hairs, and as with all flies, have only two wings. Robber Flies can be easily missed by the casual stroller through the garden as they do tend to blend in quite well on twigs and flower stems.