Deer fly
（重定向自Deerfly）
![](/Images/godic/202501/08/Chrysops_callidus5653.jpg")
![Chrysops caecutiens](/Images/godic/202501/08/Chrysops_caecutiens-s5653.jpg")
Deer flies (also known as yellow flies, or stouts in Atlantic Canada) are flies in the genus Chrysops of the family Tabanidae that can be pests to cattle, horses, and humans. A distinguishing characteristic of a deer fly is patterned gold or green eyes. The name of the genus refers to their coloration, from the Ancient Greek χρυσός (chrysós), gold, and ὤψ (ops), appearance.