In the book of Exodus, when God was causing calamities to rain down on Egypt to teach Pharaoh a lesson, the fourth plague visited upon the people there was flies. 

My Bible doesn’t say so, but I’m pretty sure they were black flies. 

I’m also halfway convinced that the plague of the flies is being visited upon East Tennessee this spring.

I just turned 40 and I have never seen biting flies as bad as they are this spring. Spend more than a half-hour outside mowing the lawn or tending to other chores without head-to-toe protective clothing and you’ll essentially be one big welt by the time you get back inside.

For those who don’t know, black flies — and their slightly larger cousin, the deer fly — are an altogether different pest from the common housefly. 

Houseflies are as annoying as the dickens but they don’t bite. Black flies and deer flies, on the other hand, bite like a son-of-a-gun. 

For reasons unknown, black flies and deer flies won’t enter a house. You can leave your front door wide open and you’ll have about six or seven thousand houseflies in a matter of minutes. But those satanic biting flies won’t venture in. It’s their only redeeming quality.

Instead of attacking you while you sleep, black flies await in ambush outside. That’s how cocky they are. They have the audacity to know that you can’t beat ‘em so there’s no point in them battling you on your turf, where they could wind up squished beneath a fly-swatter or stuck to a fly strip dangling by the kitchen sink. The second you step out under the open sun, you’re on their turf. And they’ll own you.

Deer flies and black flies are quite different, but they’re enough alike where it matters most, and that’s their razor-sharp mandibles. Deer flies are larger, carry a more painful bite, and can transmit a whole host of diseases to humans. Black flies are smaller and don’t generally transmit diseases to humans, but they tend to attack in quasi-swarms. So, pick your poison. Either way, their bites tend to cause swelling and itching and the utterance of words that can’t be used on Sundays.

Black flies, especially, are fast growers. They lay their eggs by the hundreds, and go from larvae to adults in a matter of weeks. They can go through four generations in a single summer — that little devil that was biting on your neck in May will have great-grandkids feasting on your blood by July. Bless their hearts. 

The biting flies are similar in that they require clean, moving water for laying eggs, unlike their distant cousin, the mosquito, which can make good use of dirty, stagnant water. They’re also similar in that the males feed mostly on plants while it’s the females who unleash torture on humans and animals. In fact, male deer flies feed exclusively on pollen, while male black flies feed primarily on nectar. In both species, the females are the blood-suckers. It stands to reason; only an angry, vindictive female could be as vicious and unforgiving as a biting fly. 

It’s also known that black flies will fly as far as 10 miles to find blood. And, as anyone who spends any time outside this time of year knows, there’s no escape. If you’re within that 10-mile radius, they will find you. Period. Then they’ll feast on your blood and make you like it. 

So evil are these biting flies that DEET won’t work on them. DEET will kill just about everything evil in the insect world — mosquitoes, ticks, chiggers, fleas, leaches, et cetera. But it won’t work on a biting fly. 

In fact, if you’ve ever applied DEET to ward off the little blood-sucking buggers and marveled that the Off! seems to be attracting them rather than repelling them, you may not be wrong. According to the Farmers Almanac, there is a prevailing theory that black flies are attracted to DEET.

There’s one more thing to understand about those devilish females: their blood-meal gives them the energy they need to lay eggs. So every time one bites you, if she manages to fly away before you’ve squashed her beneath the palm of your hand, guess what? She’s off to create another 300-400 of those $&*#^! things and it’s mostly your fault.

Perhaps we should count our abundance of biting flies as a blessing. After all, they’re only here because we have an abundance of clean, running water. If we didn’t, they wouldn’t be here. (In the wilds of Canada, where there is more clean, running water than anywhere else in North America, black flies are so thick they can literally drive a moose insane.) So there’s that.

No one has said for sure why we have black flies in such an abundance this spring, but it’s probably due to all the wet weather we’ve had in recent months, which had led to greater-than-normal run-off up until the last few weeks.

Some have tied that excess rainfall to climate change. Such reckonings are well above my pay-grade, but if it turns out that the millions of biting flies that are swarming in our neck of the woods this spring are due to global warming, I’ll be the first in line to sign up for an Al Gore-sponsored carbon tax. I just want to be able to mow the lawn in peace!