See also deer fly.
any of certain bloodsucking, dipterous flies, esp. any of a genus (Chrysops) of a family (Tabanidae) of insects that includes the horseflies
or deer fly
Any of various biting tabanid flies of the genus Chrysops, the females of which feed on the blood of mammals. Deerflies are smaller than horseflies and usually have a dark band on the wings.