Tabanus nigrovittatus, also known as the greenhead horse fly, salt marsh greenhead, or simply the greenhead fly, greenhead or greenfly, is a species of biting horse-fly commonly found around coastal marshes of the Eastern United States. The biting females are a considerable pest to both humans and animals while they seek a source of blood protein to produce additional eggs. Females live for three to four weeks and may lay about 100 to 200 eggs per blood meal.