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Black Horse Fly (Tabanus atratus)


Detailing the physical features, habits, territorial reach and other identifying qualities of the Black Horse Fly.

 Updated: 2/5/2018; Authored By Staff Writer; Content ¬©www.InsectIdentification.org




Large Black Horse Flies are notorious biters of horses and all things smaller, including humans, leaving behind painful sores on its victims.



Black Horse Flies are about an inch long, making them highly visible and somewhat intriguing to watch. They are fast fliers despite their hefty size. Females feed on blood, and they are not averse to taking it from anything that has it. Their mouth parts cut open flesh, allowing blood to ooze out. They use a proboscis to sponge up the blood, leaving behind an open wound. These wounds can become infected, which poses a threat to livestock health. They are also very painful bites for humans. Males do not bite and do not drink blood. Males actually drink flower nectar and spend their days looking for females to mate with.

Males and females are both completely black, but males have huge eyes that touch each other at the center of the face; the eyes of females are separated. It's the size of the eyes that strikes curiosity in most people that see them. The color of the eyes may vary depending on the lighting. Facets comprising each eye reflect light, so sometimes their eyes appear black, sometimes silver (see photo gallery) and sometimes shades of their surroundings.

This species is found in the eastern part of the continent. Females lay fertilized eggs on or near water sources. Maggots (larvae) feed on other aquatic insects and worms. Chemicals, home remedies, and special collars exist as methods used to deter the presence of Horse Flies, especially in stables.




Taxonomic Hierarchy
Kingdom: Animalia
  Phylum: Arthropoda
    Class: Insecta
      Order: Diptera
        Family: Tabanidae
          Genus: Tabanus
            Species: atratus
Identifying Information
Scientific Name: Tabanus atratus
Category: Fly or Mosquito
Size (Adult; Length): 20mm to 28mm (0.78in to 1.09in)
Colorwheel Graphic Colors: black
Descriptors: huge, plump, eyes, large,
Territorial Map
Alaska  
Hawaii  
Prince Edward Is.  
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Territorial Reach (A-to-Z)
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
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Alberta
British Columbia
Manitoba
New Brunswick
Newfoundland and Labrador
Nova Scotia
Ontario
Prince Edward Island
Quebec
Saskatchewan
Mexican National Flag Graphic
Mexico
Note: An insect's reach is not limited by lines drawn on a map and therefore species may appear in areas, regions and/or states beyond those listed above as they are driven by environmental factors (such as climate change), available food supplies and mating patterns. Grayed-out selections indicate that the subject in question has not been reported in that particular territory. U.S. states and Canadian provinces / territories are clickable to their respective bug listings.