Subject: Large wasp like fly
Location: West Cumbria , UK
June 30, 2016 6:25 am
A large flying insect landed on our balcony and I would like to know what it is. We live in Cumbria, UK and it’s the first time I’ve ever seen one of these before. I attach a couple of photos and it measures about an inch long. Can anyone identify this bug please?
Signature: P & K

Male Dark Giant Horse Fly

Male Dark Giant Horse Fly

Dear P & K,
This is a Horse Fly in the family Tabanidae and the large eyes with no space between them indicates this is a male Horse Fly.  It looks very much like this female Horse Fly from our archives, and we suspect they are the same species.  We believe we have correctly identified your species as the Dark Giant Horse Fly, Tabanus sudeticus, thanks to images on Influential Points where it states:  “The dark giant horsefly is distributed widely in northern Europe into Russia. In Britain it mainly lives in boggy areas in the north and west, although it is also quite common in the New Forest.”  A species page on Influential Points states:  “The dark giant horsefly flies in July and August and commonly feeds on the blood of cattle and ponies. In Europe …
Tabanus sudeticus flies from the end of June and through July and August. Krčmar (2005)  reports that it reaches its maximum abundance in third week of July. In Britain it mainly lives in boggy areas in the north and west, although it is also quite common in the New Forest. Tabanus sudeticus is distributed widely in northern Europe into Russia.”  Additionally, the site states:  “Tabanus sudeticus is anautogenous – it must first take a blood meal before it can lay eggs (Krčmar & Maríc, 2007 ). The dark giant horsefly undoubtedly prefers feeding on horses, cattle and deer, but it will bite man if available, as many have found to their cost. It makes a deep hum when flying around a host, but this stops abruptly just before it settles.”  If it is any consolation, only female Horse Flies are blood sucking biters.  Male Horse Flies take nectar.  BioPix has some excellent images of the Dark Giant Horse Fly.

Male Dark Giant Horse Fly

Male Dark Giant Horse Fly

Location: West Cumbria, UK

16 Responses to Male Dark Giant Horse Fly from the UK

  1. Saighdear says:

    It’s taken me a while to track this down! It’s what bit me on the Leg today in the garden. Visiting a non-stock farm and Garden plants – bare ground and inspecting some fruit bushes. NOT a wasp, Bee, or Horsefly…. and none of the rest as are commonly offered as common UK Biting insects. Bumble & Honey Bees are busy so knew it wasn’t them. Continued to harass me – thought it was protecting a Nest in the ground, etc. Weather cool today but Clear sky with cool breeze at Sea-Level N of Inverness today. The Foto fairly confirms what I saw – = like a LARGE Bluebottle with Striped Abdomen and Wings as you see.

  2. Holly Dean says:

    I have just had one of these huge things land in my garden. I am really allergic to horse fly bites and have never seen one this big. I am sure its a female too!
    We are in leafy (boggy) Bedford Town and I am really surprised to see it here.
    I know we have smaller ones in the forests around here but this is a huge surprise – I am keeping it under a glass until I can pluck up the courage to set it free.

  3. Holly Dean says:

    I have just had one of these huge things land in my garden. I am really allergic to horse fly bites and have never seen one this big. I am sure its a female too!
    We are in leafy (boggy) Bedford Town and I am really surprised to see it here.
    I know we have smaller ones in the forests around here but this is a huge surprise – I am keeping it under a glass until I can pluck up the courage to set it free.

  4. Michael says:

    There’s about 20 of these on an apple tree in a friend’s garden neer a river.

  5. Michael says:

    West Wales.

  6. Kevin says:

    Just got in my conservatory been told it’s giant dark horse fly 🪰 not boggy here but a pond few hundred m away and horse fields very close to be expected

  7. Saighdear says:

    Interesting Info about these odd sitings – of an rare insect. Once upon a time I was in contact with our local SAC( like ADAS) but those days are lonnnng since gonnn! Pity that Aacademia doesn’t keep an eye on these websites / Blogs. ( ‘F it’s not green it’s not seen )

  8. Amanda says:

    Had one of these flying around me in the garden today wasn’tsure what it was, as looked like a cross between a giant fly and a wasp… so glad it didn’t get chance to feast on me as I react badly to mosquito bites – I have about a dozen mossie bites already and I reckon that would cause me some serious discomfort. I’m in Exeter, Devon

  9. Janet says:

    Spotted one of these today in Grosmont N Yorkshire. Never seen one before. Thank you for all the information.

  10. Rob Stevens says:

    Getting a few of these around the garden especially on the lavender in the past week .
    We are in Dornoch, Sutherland, the highlands .

  11. Fran says:

    One of these horrors today in South West Wales on our sons car. All of us gave it a VERY wide berth. Horse flies have been abundant here this month. Skin So Soft by Avon works very well to keep them from biting, it has a lot of citronella in it. Horsey neighbour tipped me to it, can be used on horses as well as people.

  12. Linda Sharpe says:

    We have had several of these noisy, fast flying flies enter the house in past, hot week. We live on edge of New Forest, feel sorry for all the ponies that must get bitten. Would certainly not like contact with one!

  13. Jackson says:

    One was on our letter box in West Cumbria this morning. Whizzed past my head when my wife disturbed it.

  14. Becky Fletcher says:

    Just found one of these in our porch – wondered what on earth it was. Absolutely huge! Thankfully managed to get it our without any of us coming a cropper.
    North Wales

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