Deer flies

Definition

A common name for blood-feeding flies in the subfamily Chrysopsinae (family Tabanidae), characterized by large, brightly colored compound eyes, large clear wings with dark transverse bands, and a painful bite. They are diurnal, visually oriented hunters that feed on mammalian blood, including deer, livestock, and humans, and are mechanical vectors of diseases such as tularemia and loiasis.

Etymology

Example

Chrysops callidus, a widespread North American deer fly, inflicts painful bites on hikers and can transmit Francisella tularensis, the bacterium causing tularemia.

Synonyms

• Sheep flies
• Chrysopsinae (subfamily name)

Related Terms

• Horse flies
• Tabanidae
• tularemia
• Loa loa
• Bloodsucking flies
• Mechanical vector
• compound eyes

Usage Notes

The term refers specifically to the subfamily Chrysopsinae, not to all flies that feed on deer. Deer flies are smaller than horse flies (subfamily Tabaninae) but share the family Tabanidae and similar visual hunting behavior. "Sheep flies" is a regional synonym; the scientific name Chrysopsinae is preferred in formal contexts. The common name is sometimes applied loosely to other biting flies, but specialists reserve it for Chrysopsinae.