Horse and Deer Flies


Horse Fly

American horse fly (Sturgis McKeever, Georgia Southern University,

Horse fly

Horse fly (Sturgis McKeever, Georgia Southern University,

Deer Fly

Deer fly (Sturgis McKeever, Georgia Southern University,


Horse flies

  • large; brown or black in color
  • large colorful eyes
  • biting; sword-like piercing/sucking mouthparts 

Deer flies

  • generally smaller than horse flies
  • yellowish brown to brownish black in color
  • dark markings on wings
  • biting; sword-like piercing/sucking mouthparts 

Nesting Habits

  • develop in moist or aquatic areas like moist soil, ponds, lakes and marshes


  • females: animal blood
  • males: flower nectar


  • can travel up to a mile from breeding sites
  • inflict painful bites that can result in visible, bleeding wounds
  • transmission of tularemia and anthrax possible, but very rare
  • rarely a significant problem inside structures
  • can be a severe outdoor problem in areas near wetland habitats

IPM Recommendations

  • If large numbers of deer or horse flies are present, inspect the area for possible breeding sites. (Breeding sites may be located off property.)
  • Install properly fitting screens in windows. 
  • Use insect light traps to catch flies inside.
  • Fly traps can reduce populations outdoors. 
  • Keep doors and windows closed, or open with properly fitted screens.

Additional Resources

IPM for Flies: Integrated Pest Management in Sensitive Environments (University of Nebraska-Lincoln Extension)