Empididae(redirected from Dagger fly)
a family of dipterous insects. The body, which measures up to 15 mm in length, is elongate and slightly downy, with long legs and a needle-like proboscis. Empididae are widely distributed over the earth and are especially numerous in forests. There are approximately 2,800 species. In summer the insects swarm, performing complex mating dances. They are predators of smaller insects. Adults are found on the leaves and trunks of trees and on flowers. The larvae develop in soil and forest humus, although some larvae are aquatic, developing in streams and small rivers.