Currently viewing the category: "Horse Flies and Deer Flies"
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Subject: Huge fly out cicada?
Location: NW Iowa
August 30, 2015 8:26 pm
Found this sitting outside camper in Iowa and got a picture after the wife freaked out. Is this a horse fly?
Signature: Curious in Iowa

Female Black Horse Fly

Female Black Horse Fly

Dear Curious in Iowa,
Because of the spacing between the eyes, one can tell that this Black Horse Fly,
Tabanus atratus, is a female.  Only female Horse Flies bite and suck blood from mammals, and if they cannot find a four footed host, they will bite humans.  According to BugGuide:  “Although Tabanus atratus do not often bite humans, when it does happen it leaves painful memories. This fly can also transmit bacterial, viral, and other diseases such as surra and anthrax, to both humans and other animals through its bite.  The effect of T. atratus on livestock can be a serious problem. Blood loss and irritation from the flies can severely affect beef and milk production, as well as grazing. Livestock usually have no way of avoiding the painful bites, and millions of dollars have been spent trying to control these pests. (Long 2001)”

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Subject: Black Moth?
Location: Bay Area, California
August 20, 2015 10:57 am
Just found this moth like creature in my garden this morning (8/19/15) in Fremont, California, zip code 94536. What is it?
Signature: Elizabeth Cerutti

Female Western Horse Fly

Female Western Horse Fly

Wow Elizabeth,
This is one gorgeous image of a female Western Horse Fly,
Tabanus punctifer, who can be easily distinguished from her sexually dimorphic mate by the spacing between her eyes and the color and pattern of the white hair on her thorax.  According to BugGuide:
“From Middlekauff & Lane:
Female: A large, dark-colored horse fly. Easily recognized by the following characteristics: mesonotum covered with creamy hair over a dark reddish background: remainder of thorax dark brown, with concolorous hair: wings brown, paler posteriorly, the cross-veins and furcation distinctly margined with brown; legs black, except basal third of fore tibiae, which are creamy white with long white hair; abdomen black.
Male: Color as in female except that the white of the mesothorax is confined to a lateral band and the outer margin of the scutellum.”
The pastel colors of the succulent plant act as a perfect background for this striking fly.  Female Horse Flies are blood suckers that feed on warm blooded animals, and many species are not at all opposed to sucking human blood.

Wow, thanks for such a quick, complete and descriptive answer!  I had no idea it was in the fly family, and a dreaded horse fly at that. When I was growing up on Long Island, NY, we used to try and dodge horse flies in the swimming pool in the summer.  They were so smart, they used to hover right above and wait for us to surface for air.  Hell of a welt.  This one today in the garden was easily an inch long.
Thank you, again.
Best regards,
Elizabeth

When we were putting together our response for you, we searched our archives for an image of a male Western Horse Fly to no avail.  Should you happen to see one, please take an image and send it to us.  Here is a BugGuide image of a male Western Horse Fly.

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What's That Bug? does not endorse extermination

Subject: Flying striped bodied moth?
Location: Central KY
August 12, 2015 1:53 pm
A big bug was caught in an old web across our glass door. We watched all day as it struggled to get free. I took pictures so I could look it up. We are new to central KY, USA and I have never seen this bug in my life (I come from northern IN).
The wings were clear except for black lines. The body was large, round and striped a yellow and dark brown. A furry head topped it off with a hose type nose and large ovalish eyes. It was quite a specimen!
P.S. It eventually freed itself.
Signature: V

Horse Fly

Horse Fly

Dear V,
One can tell by the spacing between the eyes that this Horse Fly is a female.  Female Horse Flies bite and suck blood from vertebrates, especially mammals, while male Horse Flies do not bite and feed on nectar from flowers.  Based on matching images on BugGuide, we believe we have correctly identified your Horse Fly as
Tabanus sulcifrons.

Horse Fly

Horse Fly

Wow! Thank you for taking the time to reply!
I had the feeling it was a biting type of insect and told my son so.
I am so grateful for your letter!
Bless you,
V

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Subject: What’s that bug
Location: Oxfordshire
August 10, 2015 2:27 pm
Hi Bugman
I captured this beauty in Oxfordshire UK and have been struggling to identify it. Can you help ?
Signature: Gordon Sheret

Four Lined Horse Fly

Four Lined Horse Fly

Dear Gordon,
We immediately recognized your fly as a male Horse Fly in the family Tabanidae, and our search for its species identity led us to the Influential Points:  How to Catch Horse-Flies page and an image identified as
Atylotus rusticus (scroll down) with this information:  “As well as catching vast numbers of the commoner non-man-biting species (in particular Tabanus bromius), we have found host-seeking females of the very rare and local Atylotus rusticus both within and somewhat outside its usual haunts.”  An image on Nature Photo has convinced us that this is in fact a male Atylotus rusticus.

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Subject: Is this a Bot Fly?
Location: South Windsor ct
July 24, 2015 4:08 pm
Hello I am in south Windsor ct and the almost 2 inch fly wondered into our shop.
I looked up bot fly and saw there was different types and did find one that looked like this.
Signature: Is this a bot fly?

Female Horse Fly

Female Horse Fly

This is most certainly NOT a Bot Fly, but a Horse Fly in the family Tabanidae, and based on the spacing between the eyes, it is a blood sucking female.  We believe it is Tabanus stygius based on this BugGuide image.

Thank you Daniel, I only asked because there was a Bot fly found in Westport Ct.
Ty,
Michael

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Subject: What am I?
Location: Pennsylvania
June 5, 2015 10:13 pm
Can’t seem to find what this guy is.
Signature: Heather Cookson

Mystery Thing

Horse Fly Egg Mass

Dear Heather,
Your mystery thing has us quite stumped.  It does not look like an insect, but it appears that it might have been produced by an insect.  We do not believe this is an egg mass, but it might be some type of shelter.  The “scales” look somewhat like seeds.  Could you please provide more details on where it was found and regarding its size.  Perhaps one of our readers will be able to contribute some valuable information.

Update:  Horse Fly Egg Mass
Immediately after posting, we received a comment identifying this as a Tabanid or Horse Fly Egg Mass, and a link to BugGuide.  Mystery solved thanks to a diligent reader. 

Eric Eaton Confirms
Hi, Daniel:
That is a batch of horse fly or deer fly eggs.
Eric
author, Kaufman Field Guide to Insects of North America
http://bugeric.blogspot.com/

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What's That Bug? does not endorse extermination