They can be found all over the North East and their bite will hurt.
Horseflies may look like ordinary flies but they are super-charged with razor-sharp jaws, a mean attitude, and an appetite to match.
And it’s the women who are the deadliest of the species.
We’ve been looking at what they are – and what to do if you’re unfortunate enough to be bitten.
What’s the problem…they’re only flies?
We’re used to warnings about biting insects at this time of year, but it’s not just the midges of Kielder Forest and mosquitoes that are thirsty for our blood.
There’s another, larger biting creature that thrives in the warmer weather, and it’s on the look-out for its next meal – you.
Horseflies, also known as clegs, have razor sharp jaws and can cause a very painful bite.
Unlike midge bites, it can take much longer to recover from a horsefly bite because they cut into the skin rather than pierce it, which can cause the wound to become infected.
Some people can also suffer extreme allergic reactions to horsefly bites.
So, nasty flies?
Yes. The Northumberland Wildlife Trust say the biting insect can be a nuisance during the summer and especially in hot thundery weather.
They say the Notch-horned Cleg-fly is a common species of horse-fly, which lives in long grassland and damp woodland habitats.
A spokesperson said: “The females have sharp biting mouthparts and feed on the blood of large mammals, usually cows and horses, but will happily drink the blood of humans too.
“The males lack these mouthparts, and so feed on nectar.
“Females wait in shady areas for their prey to pass-by, locating it by sight with their large compound eyes.”
Do they do ANY good at all?
The Trust says horseflies are considered pests due to the bites which they can inflict, causing blood loss and diseases in some species.
However, they are still a link in the food chain and are predated upon by birds and other animals.
Where are they found?
They’re large, dark-coloured flies which are around 1cm-2.5cm in size. They’re widespread over the whole North East but generally found near to cattle, horse stables, ponds, pools, woodlands, and grassy areas.
Don’t read too much into their name – ‘horseflies’ – because they’ll quite happily chomp on any large warm-blooded mammal, including – yep, you guessed it – people.
They have jagged, saw-like teeth which slice open skin, then they release an anti-coagulant to stop the blood from clotting while they enjoy their meal.
What’s the damage?
First off, you’ll know about it pretty quickly. The bites are painful and itchy.
Horsefly bites develop into large, red, itchy, swollen bumps within minutes. For most people they’re completely harmless, but they’re extremely uncomfortable.
Some people also report feeling hot, weak, nauseous or dizzy.
An infected bite can result in redness, oozing, and extreme pain.
In exceptional cases some people can suffer an allergic reaction with symptoms including dizziness, wheezing, difficulty breathing, a blotchy skin rash and severe swelling that may be visible in your lips or tongue.
If you suffer any of these reactions, seek medical help immediately.
What happens if I’m in the middle of the countryside?
It’s important to keep the bite clean because if bacteria gets into the skin it can become infected.
It’s best to clean the wound with an antiseptic soap and warm water if you can.
Apply an ice pack to help sooth the area and stop the itching.
Doctors normally recommend using an over-the-counter steroid cream and Ibuprofen gel can also help the swelling.
And it goes without saying that you should avoid scratching the bite. It won’t stop the itching and could damage the skin, increasing the risk of developing an infection.