black horse fly

(Tabanus atratus)

Conservation Status
black horse fly
Photo by Greg Watson
  IUCN Red List

not listed

     
  NatureServe

not listed

     
  Minnesota

not listed

     
           
           
           
 
Description
 
 

Black horse fly occurs in the United States mostly east of the Great Plains and in adjacent Canadian provinces. At ¾ to 1 (20 to 25 mm) in length, it is one of the largest horse flies in North America. Some sources, including National Audobon Society Field Guide to Insects & Spiders (1980) and some Websites, suggest that it can get up to 1 (28 mm) long, but this is not widely accepted.

There are two large compound eyes and three simple eyes (ocelli). On the male the compound eyes meet at the top of the head. On the female they do not. The third segment of each antenna has a prominent tooth-like process at the base.

The body is stout. The body and wings are black, purplish-black, or dark brown. The thorax is covered with short, fine, black, yellowish, or whitish hairs. The wings are entirely dark, not patterned. There is no spur at the tip of the fourth segment (tibia) of the hind leg.

 
     
 

Size

 
 

Total Length: ¾ to 1 (20 to 25 mm)

 
     
 

Similar Species

 
     
     
 
Habitat
 
 

Agricultural and suburban areas; any moist habitat with livestock or other large mammals

 
     
 
Biology
 
 

Season

 
 

Spring to late fall

 
     
 

Behavior

 
 

Black horse fly females prefer to bite cattle and other livestock. It is unusual for them to bite humans, but when they do the bite is memorable. Males do not bite.

 
     
 

Life Cycle

 
 

 

 
     
 

Larva Food

 
 

 

 
     
 

Adult Food

 
 

Females feed on mammalian blood. Males feed on nectar and plant juices.

 
     
 
Distribution
 
 

Distribution Map

 

Sources

24, 27, 29, 30.

 
  7/31/2021      
         
 

Occurrence

 
 

 

 
         
 
Taxonomy
 
 

Order

Diptera (gnats, mosquitoes, true flies)  
 

Suborder

Brachycera (circular-seamed flies, muscoid flies, short-horned flies)  
 

Infraorder

Tabanomorpha  
 

Superfamily

Tabanoidea  
 

Family

Tabanidae (horseflies and deerflies)  
 

Subfamily

Tabaninae (horse flies)  
 

Tribe

Tabanini  
 

Genus

Tabanus  
       
 

Subordinate Taxa

 
 

Two varieties have been described, but these are not widely recognized.

black horse fly (Tabanus atratus atratus)

black horse fly (Tabanus atratus fulvopilosus)

 
       
 

Synonyms

 
 

Tabanus fulvopilosus

Tabanus nantuckensis

Tabanus niger

Tabanus validus

 
       
 

Common Names

 
 

black horse fly

mourning horse-fly

 
       

 

 

 

 

 

 

Glossary

Ocellus

Simple eye; an eye with a single lens. Plural: ocelli.

 

 

 

 

 

 
 
Visitor Photos
 
           
 

Share your photo of this insect.

 
  This button not working for you?
Simply email us at info@MinnesotaSeasons.com.
Attach one or more photos and, if you like, a caption.
 
 

Randy G

 
 

I saw it fly into my shed pretty hard and fall onto the ground near my bird bath. I thought it was a cicada so I went to investigate. Took awhile to spot it on the ground, but when I did i knew it was not a cicada. We gained each other's trust to where I used a stick to let it crawl on and set it up on the bird bath where it seem to drink and clean its beak. It eventually flew towards my face so I scrammed!

  black horse fly  
 

Greg Watson

 
 

I looked at the pictures of the Black Horse Fly, Tabanus atratus, at Minnesota Seasons and noticed that there isn’t a good closeup of one. I took the pictures in my backyard in La Crescent.

  black horse fly  
           
        black horse fly  
 

Sue Roy

 
 

Huge Fly

 
 

I am in Itasca County and saw this huge guy on the sidewalk at 7 am and have never seen anything like this. I found your website and realized they are not normally in our area so I thought I would report my sighting.

Has anyone seen this before? It’s the size of a quarter for sure and reminds me of a horsefly with a huge “beak” to bite you with.

  black horse fly  
         
  black horse fly   black horse fly  
         
 

I decided to measure it since it was still there.

I did a little research and it looks like it is a black horse fly and not normally in this area. It is a biggun'!

  black horse fly  
 

Shelby

 
 

So dark and large, she seemed velvety!

 
    black horse fly   black horse fly  
 

Amy Moore

 
 

this site used to be location of dairy Cows and Horses

 
    black horse fly      
 

Norm & Peg Dibble

 
  Not sure what kind of fly this was (maybe you do), but Norm didn’t want to get too close! Darth Vader? It was on our patio umbrella post. Yikes   black horse fly  
           
 
MinnesotaSeasons.com Photos
 
 

 

 
           
           

 

Camera

     
 
Slideshows
 
 
     
     
     

 

slideshow

       
 
Visitor Videos
 
       
 

Share your video of this insect.

 
  This button not working for you?
Simply email us at info@MinnesotaSeasons.com.
Attach a video, a YouTube link, or a cloud storage link.
 
 

 

 
     
     
       
       
       
 
Other Videos
 
  Black Horse Fly (Tabanus atratus)
Douglas Heusser
 
   
 
About

Published on May 25, 2017

Macro video of a Black Horse Fly (Tabanus atratus) filmed with a Tamron 90mm lens on a Canon T5

 
  Horse Fly (Tabanidae: Tabanus) Behavior
Carl Barrentine
 
   
 
About

Published on Jun 28, 2011

I observed two flies exhibiting this behavior (i.e., employing outstretched forelegs as either a funneling or gathering technique). I'm speculating that this may be a feeding behavior. Could this individual be gathering organic debris on foreleg tarsal setae. These large, biting flies are pollen-eaters, too. Photographed at the Turtle River State Park, North Dakota (27 June 2011).

 
  Black Horsefly (Tabanus atratus) - Laying Rows of Eggs
Nature's Wild Things
 
   
 
About

Published on May 28, 2017

Black Horsefly (Tabanus atratus)

Laying Rows of Eggs

Video 30 sec long 90% speed - Audio none

Cabarrus County, North Carolina, United States

Photo Walk - 05-26-2017

 
       

 

Camcorder

 
 
Visitor Sightings
 
           
 

Report a sighting of this insect.

 
  This button not working for you?
Simply email us at info@MinnesotaSeasons.com.
Be sure to include a location.
 
  Randy G
8/23/2021

Location: South Saint Paul, MN

I saw it fly into my shed pretty hard and fall onto the ground near my bird bath. I thought it was a cicada so I went to investigate. Took awhile to spot it on the ground, but when I did i knew it was not a cicada. We gained each other's trust to where I used a stick to let it crawl on and set it up on the bird bath where it seem to drink and clean its beak. It eventually flew towards my face so I scrammed!

black horse fly  
  Greg Watson
6/27/2021

Location: La Crescent, MN

I looked at the pictures of the Black Horse Fly, Tabanus atratus, at Minnesota Seasons and noticed that there isn’t a good closeup of one. I took the pictures in my backyard in La Crescent.

black horse fly  
  Sue Roy
7/15/2021

Location: Cohasset Elementary School in Cohasset

I am in Itasca County and saw this huge guy on the sidewalk at 7 am and have never seen anything like this. I found your website and realized they are not normally in our area so I thought I would report my sighting.

Has anyone seen this before? It’s the size of a quarter for sure and reminds me of a horsefly with a huge “beak” to bite you with.

black horse fly  
  Mabeln
6/17/2021

Location: Otsego, MN

I’ve never seen a fly that big before!

 
  Shelby
8/27/2020

Location: Aiken, South Carolina

Very large for a fly. So black it seemed velvety. Resting on my porch.

black horse fly  
  Amy Moore
8/12/2020

Location: Maplewood History Barn Maplewood, MN

this site used to be location of dairy Cows and Horses

black horse fly  
  Norm & Peg Dibble
7/5/2019

Location: Maple Grove, MN

Not sure what kind of fly this was (maybe you do), but Norm didn’t want to get too close! Darth Vader? It was on our patio umbrella post. Yikes

black horse fly  
           
 
MinnesotaSeasons.com Sightings
 
 

 

 

 

 

Binoculars


Created: 7/7/2019

Last Updated:

About Us | Privacy Policy | Contact Us | © 2022 MinnesotaSeasons.com. All rights reserved.