Deerfly | ©Patrick Zephyr (Massachusetts, US)
Deerflies belong to the genus Chrysops into the family Tabanidae. Among other features, these tabanids are distinguished by the naked eye, often with spots or bands of different color. Antennae are cylindrical and longer than the head. The forehead is broad and has a very apparent frontal callosity .
While female deerflies feed on blood, males instead collect pollen. When feeding, females use knife-like mandibles and maxillae to make a cross-shaped incision and then lap up the blood. Their bite can be extremely painful, and allergic reaction from the saliva of the fly can result in further discomfort and health concerns. Adults are potential vectors of tularemia, anthrax and loa loa filariasis .