Robber fly

Adults have piercing-sucking mouthparts. Adult robber flies perch on stems of low plants or other objects and attack prey in the air. They feed on bees, beetles, dragonflies, other flies, grasshoppers, leafhoppers, wasps, and other insects. Larvae live in the soil, in wood and other habitats, feeding on organic matter, other arthropods such as white grubs, beetle pupae and grasshopper egg masses, and they may be carnivorous.
http://insects.tamu.edu/fieldguide/cimg228.html