Eastern-us-coast
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Tabanus nigrovittatus
greenhead horse fly, salt marsh greenhead, greenhead fly, greenhead, greenfly
Tabanus nigrovittatus, commonly known as the greenhead horse fly or salt marsh greenhead, is a biting horse fly species endemic to coastal salt marshes of the eastern United States. Adult females are aggressive blood-feeders that require vertebrate blood for egg production, while males do not feed on blood. The species is smaller than most horse flies, approximately the size of a house fly. Larvae develop in intertidal salt marsh mud for one to two years, preying on other invertebrates. Adults emerge in late spring and are most active from late June through August. The species is a significant human and animal pest, with populations managed through black box traps rather than insecticides due to ecological concerns.