Currently viewing the category: "Horse Flies and Deer Flies"

Subject:  Can you confirm my suspicion that this is a horsefly?
Geographic location of the bug:  Scotland
Date: 06/29/2018
Time: 02:17 PM EDT
Your letter to the bugman:  Hi, I have been finding these guys lying on their back in my back garden regularly (4 in the last 2 days). I thought they may have been honey bees.
I flipped them all back onto their feet only for them to roll back over.  It has been unusually warm here.
They are around 20mm in length.
I am a little concerned by the number of them appearing in my back garden because my 2 young children play there regularly.
Thanks in advance.
How you want your letter signed:  Kev

Horse Fly

Dear Kev,
This sure looks like a Horse Fly to us.  The wing venation pattern matches the diagram posted to BugGuide.

Subject:  Unidentifed Fly
Geographic location of the bug:  Somerset, UK
Date: 06/25/2018
Time: 06:45 AM EDT
Your letter to the bugman:  This fly was in my house in Somerset, UK this morning. I am unable to identify it because it was so large. The body was 35mm long. The eyes were green matt (olive/emerald). It buzzed loudly. This is much larger than the Giant Horse Fly known in the UK. Please can you help?
How you want your letter signed:  Liz

Horse Fly

Dear Liz,
This is a female Horse Fly in the genus Tabanus.  Horse Flies often plague livestock by biting to feed on blood, but only the females bite.  We located an article on Huffington Post that states:  “
Forget giant hogweed, horseflies are the newest atrocity plaguing the nation.  People across the UK have been sharing photos of their horrendous horsefly bites – and it’s enough to put you off your dinner.  The flies, which are large, dark-coloured and 1-1.2cm in size, are often found loitering around farm animals (such as horses and cattle), ponds and other grassy areas.  Their bites cut the skin, rather than piercing it, which can be very painful.”  Your fly might be the Dark Giant Horse Fly, Tabanus sudeticus.

Thank you for your quick reply. I am very familiar with our common horse flies but this one was nothing like them in size. This one was 3.5cm (35mm) long with a much wider body and not the normal 1-1.2 cm. I have also looked up the Dark Giant Horse Fly but the recorded maximum size for that type seems to be 2.5 cm. This was definitely something you would not like to bite you. I am now wishing I had trapped it rather than letting it go!
Many thanks for getting back to me.
Liz

Subject:  What’s this clutch?
Geographic location of the bug:  Southern Ontario
Date: 06/21/2018
Time: 08:19 PM EDT
Your letter to the bugman:  Looked up and saw this on a Norway Maple leaf.  Moist to the touch.   Looked like a fat little moth.  Actually made of overlaid cylindrical units.  Egg clutch?
How you want your letter signed:  Mike

Horse Fly Eggs

Dear Mike,
These sure look like Horse Fly eggs to us.  Here is a BugGuide image for comparison.  According to Purdue University:  “Females search for a place to lay a single mass of eggs consisting of 100-800 eggs, depending on the species. Egg masses of most species that have been studied are laid on the underside of leaves or along the stems of emergent vegetation growing in wetlands. Hatching occurs in approximately 2-3 days, and newly emerged larvae drop down into water or saturated soil in which they feed and develop.” 

Horse Fly Eggs

Thanks! No water near there for the larvae to drop into and mine were a silvery-blue colour (vs the pic; likely varies anyway, right?) but if it’s any of those bitey buggers (Tabanidae), then I don’t feel bad for disturbing it.  Now I know.  Tough to pick the keywords to search these things.  You all do a very cool service.  Great site too. Thanks again.
Mike
Hi again Mike,
Online images of Horse Fly eggs do vary in color.  Larvae of some species will develop in damp soil.
On subsequent inspection, it seems that egg mass must have just been fresh; thus the bright colour.  They dried to a dark brown/black.
Thanks for providing that additional information.

Subject:  Please ID this bug
Geographic location of the bug:  Saint Johns Florida
Date: 05/31/2018
Time: 05:30 PM EDT
Your letter to the bugman:  Inhave a pesky, biting insect that looks like a fly, about the size of one and is as quick as one.  The only thing is that it bites/stings.  It has a touch of red on it and is a little larger than one.  It’s very aggressive and leaves a big bump with it’s bite/sting.
How you want your letter signed:  Quckly

Yellow Fly of the Dismal Swamp

Dear Quckly,
While we empathize with your situation, we are nonetheless quite amused to learn that the common name of the Horse Fly,
Diachlorus ferrugatus, that is troubling you is, according to BugGuide, the Yellow Fly of the Dismal Swamp.  According to Featured Creatures:  “The female yellow fly is one of the most serious biting fly pests wherever it occurs (males do not bite). It attacks man vigorously, and the bites are painful, often causing large and itchy swellings. Although it attacks throughout the day, it is most active during the late afternoon and on cloudy days. It is especially common near large bodies of water, but tends to remain in or near forests. It is one of the few tabanids that attacks indoors. All exposed parts of the victim’s body may be attacked, and since the flight is rather quiet, a person is not aware of the flies until the sharp pain of the bite is felt. Domestic animals, including dogs, are attacked readily, although the fly’s preference for shade makes it less of a pest to cattle and horses in open pastures. Flies are on the wing in Florida from March to November, although the peak season is April through June.”  According to BugGuide:  “one of the first horse fly species described from North America.” 

Yellow Fly of the Dismal Swamp

Subject:  Some type of fly
Geographic location of the bug:  SW Pennsylvania
Date: 05/29/2018
Time: 11:47 PM EDT
Your letter to the bugman:  I’ve recentky been bitten to hell and back by these things. There is a development starting behind my house and all these new bugs have started to come out of the woods since they are clearing the area. The itch
How you want your letter signed:  Doesn’t matter

Female Horse Fly

This is a female Horse Fly and it is possible that habitat destruction has affected its food source.  Female Horse Flies are blood suckers and they might have been feeding on livestock or deer, but they are opportunistic and they will bite humans if no other prey is available.  The two species your individual closely resembles are Tabanus limbatinevris pictured on BugGuide and Tabanus sulcifrons also pictured on BugGuide.

Female Horse Fly

Subject:  Flies
Geographic location of the bug:  Cootamundra, NSW. Australia
Date: 02/20/2018
Time: 12:55 AM EDT
Your letter to the bugman:  Wanting to know what sort of fly this is? Thank you.
How you want your letter signed:  Graham

Horse Fly or Bee Fly???

Dear Graham,
Our initial thought is this must be a Horse Fly (called March Flies in Australia) from the family Tabanidae, but there are no similar looking images on the Brisbane Insects site.  The white edge on the compound eye is a trait found in several Bee Flies on the Brisbane Insect site that share that trait.  We are going to request assistance from our readership with this identification.