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

Subject:  Beauty and a beast
Geographic location of the bug:  Nova Scotia, Canada
Date: 07/19/2018
Time: 05:41 AM EDT
Your letter to the bugman:  Hi Bugman!
I was recently working on stream habitat assessments …  On another day, we were looking at rocks for freshwater benthic macroinvertaebrates and I found this worm-like creature that was not on our super-simplified ID guide. It was translucent and you could see everything shifting around when it moved. As I was trying to take photos and video of it moving/wriggling, it bit me (or stung/poked me), drawing blood and I dropped it. Luckily (or unluckily depending on how you look at it, I suppose), we came across another one later. As I watched it move this time, I believe what I might have gotten stuck with its back end grippers which it seems to use to grip onto the rock face. I was looking at some other aquatic larval stages for different insects and cam across an image of crane fly larvae that looks similar, but again, I’m not really sure and was hoping you might have a better idea.
Here’s hoping!
How you want your letter signed:  Many thanks, Van

Horse Fly Larva

Hi Van,
We believe your guess that this is a Crane Fly larva is incorrect, but we do believe you have the insect order correct.  We believe this is an aquatic Horse Fly larva and according to the Missouri Department of Conservation:  “The larvae of horse and deer flies are fairly straight, segmented, wormlike maggots that are tan, whitish, or brownish. Several fleshy rings circle the body. They are robust, circular in cross-section, and taper at both ends. There are no true legs, although fleshy, nobby pseudopods or prolegs are present. In relaxed specimens, a thin, pointed breathing tube extends from the hind end to protrude above the water surface.”  BugGuide has an account of a person being bitten by a Horse Fly larva.

Horse Fly Larva

Thanks Daniel!
Go figure, the horse flies are still jerks even before they grow up 😀
Thanks for the help.

Subject:  What’s this big black fly with yellow middle?
Geographic location of the bug:  Tweed River, Pittsfield VT
Date: 07/17/2018
Time: 02:07 PM EDT
Your letter to the bugman:  Please help us identify this enormous fly or whatever the heck it is!! We took the kids and dog for a swim in the River at the end of a hot day and these flies were relentless! We’ve never seen them before and I can’t find anything similar on the internet. If anyone knows what this is, it’s you.
How you want your letter signed:  Thank you!

It’s an orange banded horse fly! I posted to Facebook and a friend helped us identify. So no need to waste your time on us. Horse fly?? I feel kinda silly I even asked!! LOL.
Thank you!
Michelle D.

Orange Banded Horse Fly

Dear Michelle,
After verifying the identity of this Orange Banded Horse Fly,
Hybomitra cincta, on BugGuide, our first thought is that it is a stunningly beautiful Horse Fly and BugGuide does note:  “Females have first three segments of abdomen orange, rest of abdomen black (sharply delimited), and wings dark. Males are harder to identify.”  Don’t underestimate the amazing diversity of Horse Flies.  Some especially striking examples from our site are the only green North American Horse Fly Chlorotabanus crepuscularis, the American Horse Fly and the Western Horse Fly.

Subject:  Large Fly
Geographic location of the bug:  Michigan
Date: 07/15/2018
Time: 09:23 AM EDT
Your letter to the bugman:  I saw this fly sitting on my trash can. Hot weather. The ledge he is sitting on is about 1 1/4″ wide. I can’t find any Google images that match. Can you identify this bug?
How you want your letter signed:  Tom

Horse Fly: Tabanus stygius

Dear Tom,
This is an impressive female Horse Fly and we believe we have correctly identified her as
Tabanus stygius thanks to this BugGuide image.

Horse Fly: Tabanus stygius

Thank you for your response and identifying the fly. I’m impressed you replied so quickly.  Thank you.

You happened to send your request during the window of time in the morning we try to devote to responding.

Subject:  Deer fly?
Geographic location of the bug:  Whitmore Lake, MI
Date: 07/14/2018
Time: 10:12 AM EDT
Your letter to the bugman:  Hello your Bugness,
Is this a deer fly?  It’s not orange like descriptions I’ve read.
How you want your letter signed:  Curious in Whitmore Lake

Striped Horse Fly

Dear Curious in Whitmore Lake,
Deer Flies and Horse Flies are in the same family, Tabanidae, and your individual is a Horse Fly.  The space between the eyes indicates it is a blood sucking female.  Only female Horse Flies and Deer Flies Bite.  Males do not bite.  We believe we have identified your female Horse Fly as a Striped Horse Fly,
Tabanus lineola, thanks to images posted to BugGuide.

Subject:  horsefly?
Geographic location of the bug:  Florida
Date: 07/05/2018
Time: 09:13 PM EDT
Your letter to the bugman:  Is this a horsefly?
How you want your letter signed:  uh

Deer Fly

Dear uh,
This is a Deer Fly, not a Horse Fly, but they are in the same family Tabanidae, so they share many similarities.  We believe your individual is in the genus
Chrysops, and according to BugGuide:  “100 spp. in 2 subgenera in our area.” Alas, we haven’t the necessary skills to provide a conclusive species identification.

Subject:  What the hell is it??
Geographic location of the bug:  Bassenthwaite Cumbria England
Date: 07/01/2018
Time: 12:20 PM EDT
Your letter to the bugman:  Please help me with what the hell this is!!
How you want your letter signed:  Gail.

Giant Horse Fly

Dear Gail,
Congratulations on being chosen Bug of the Month for July 2018 with your query of this Giant Horse Fly, in the genus
Tabanus.    You are the third identification request we have received this week, and we quickly linked to a Huffington Post posting.  We cannot tell due to the camera angle if this is a male or female Giant Horse Fly.  Males in the genus have compound eyes that nearly touch one another while the eyes of the female have a space between them.  Only the female Giant Horse Fly will bite as the male does not feed on blood which is necessary for the female to lay viable eggs.  That blood generally comes from livestock including horses and cattle, but when livestock or other large mammals are not available, the opportunistic Horse Flies might bite humans, but try to remember after viewing the images on that Huffington Post article that most encounters between humans and Horse Flies do not end with bites.  The Gadfly that tormented Io in Greek mythology was most likely a Giant Horse Fly as Wikipedia confirms.  Long ago, the mythological Io was also the inspiration for the name of the lovely North American Io Moth as was consistent with the pattern set with 18th Century taxonomists like Linnaeus and Fabricius.