But those are minor inconveniences compared with the scourge that arrives in late May, when bloodsucking black flies hatch by the billions and force humans into an unaccustomed position at the bottom of nature's food chain.

"They fly in your eyes," said Judy Harry, a Johnsburg resident who grew up in this ancient mountain range. "They fly in your ears. They go up your nose, get in your hair. They actually remove pieces of your flesh."

The black fly season - sometimes called the fifth season in the Adirondacks - lasts for up to a month, including most of June. Few aspects of everyday life escape the insect's influence. Hikers stay at home. Gardeners stay indoors.

"You go through a very long winter and it finally gets nice out," said Kathy Vanselow, whose Brant Lake company, Vectortech, specializes in black fly control. "You only have a few months when you can work outside in the garden or paint your house. And black flies cut that time in half."

Relentless swarms of biting flies make parts of the Adirondacks so inhospitable that tourism grinds to a halt. Some inns simply shut down for the few weeks after Memorial Day. Golf course business falls off to a trickle. Fishermen suddenly comprehend what it is like to be bait.

"They snicker at the flat-landers who come up during the bug season," said R.W. Groneman, a spokesman for the New York State Department of Environmental Protection. "Don't you know enough to stay out of the woods?"

Unlike mosquitoes, which insert their tubular snouts directly into a capillary like an oil driller sinking a well, the tiny black fly obtains its blood meal by tearing through the skin with razor-sharp teeth, like a bulldozer opening a strip mine.

Then, with its spongelike mouth, the black fly drinks up a pool of blood. Its saliva, which acts as an anticoagulant, leaves a rivulet of blood flowing long after the bug has gorged and flown.

A cloud of black flies can leave a victim with oozing, poxlike welts that take weeks to subside.

"You can't get from your car to the building without being surrounded by hundreds of them," said Linda Russell, who works at the Elk Lake Lodge, an expensive mountain inn that closes for three weeks rather than subject its guests to the torture.

Some victims have allergic reactions that cause horrendous swelling. Barbara McMartin, an author of Adirondack trail guides, said her daughter's ear once ballooned alarmingly. "It was larger than her head, I think," she said.

In North America, black flies do not transmit any serious human illnesses (though they do pass some infections among livestock). But in the tropics, the flies transmit a parasitic worm that causes onchocerciacis, the most common cause of blindness in the world.

In the Adirondacks, where the gnatlike black flies are more of a threat to sanity, some proud locals regard their flies as the worst in the Northern Hemisphere, making a validation of the hardships one must endure to live in this harsh but beautiful environment.

One town, Inlet, went so far as to advertise itself as the Black Fly Capital a few years back, until merchants suggested that most tourists failed to appreciate the humor.

"You don't advertise your bad points," said Grover Hugelmaier, the owner of an Inlet gift shop.

Some Adirondackers regard the insects almost benevolently - as nature's way of keeping the human pests from overwhelming the wilderness.

"If we had warmer weather and fewer black flies, there would probably be a million people living up here," said Gary Randorf, a senior counselor with the Adirondack Council, a preservation group. As it is, only 130,000 people live in the Adirondacks, an area the size of Vermont.

Despite the bug's longevity - black flies have been around for 160 million years - humans have been trying to control the insects ever since European explorers landed in North America and discovered the ravenous insects. ("The worst martyrdom I suffered in this country," wrote a priest traveling in the north country in 1624.)

Early travelers to the northern woods, where the insects thrive in clear, cool streams (some say black flies are the Maine state bird), learned right away that swatting offered no relief to bugs that can alight and chow down undetected.

Recreationists who flocked to the Adirondacks in the 1800s - some lured by accounts that soft-pedaled the effects of black flies - filled smudge pots with smoldering green twigs and lichen to drive off the flies. The noxious smoke gave only partial relief. The smudge pots also caused a dramatic increase in forest fires.

Nineteenth-century woodsmen also experimented with various elixirs and repellents, some of which were as ineffective as the stuff that modern chemistry has devised.

One repellent consisted largely of tar oil, said Bill Healy, a Ballston Lake author and outdoorsman.

"After about two weeks of applications, it really got into the skin and was pretty effective, as long as you didn't bathe," he said.

Victorian outfitters devised ridiculously encumbering solutions like head nets, which are still in use today. But most garments are no match for black flies - although long pants obviously are better than gym shorts.

"They even try to get in through the seams of your clothing," said William Webb, a Syracuse bookkeeper and hiker. "They're very ingenious little critters."

After World War II, public officials embraced the idea of mass extermination by aerial application of insecticides such as DDT and methoxychlor.

But the chemicals tended to provide only temporary relief until a new batch of insects hatched or opportunists blew in from a neighboring, untreated area. They also indiscriminately killed all insects, including beneficial pollinators such as bees.

In the last 10 years, all but three Adirondack towns have discontinued aerial spraying and have begun applying a new bacterial agent, bacillus thuringiensis israelensis (BTI). The insecticide, a naturally occurring bacterium that is considered environmentally benign, kills black fly larvae in the streams where they lay their eggs.

"A solution like BTI doesn't come along very often," said Daniel P. Molloy, an entomologist who heads the New York State Museum's field office in Cambridge, N.Y. Molloy spent 20 years studying black flies and helped test BTI's effectiveness.

BTI is applied by crews that must trudge through the countryside early in the season and pour carefully measured portions of the chocolatey liquid into every stream where the black flies breed. In some towns, the crews must bushwhack through miles of wilderness to treat dozens of streams.

The aim is to kill the black fly larvae before they become adults - specifically, adult females, which require a protein-rich meal of blood before they can lay a batch of eggs. (Male black flies, like male mosquitoes, do not bite.)

The insecticide is 90 percent effective, Molloy said. But the application of BTI is labor-intensive and expensive. Only a few towns that are heavily dependent on tourism say it is worth the effort.

"Without tourists, we have nothing," said George T. Hiltebrant, the supervisor in the town of Webb, which includes tourist areas such as Old Forge, which is in the third year of a BTI program. "If we didn't have a control program, our golf course wouldn't do any business in June."

But many residents in the impoverished region, who say they have built up a tolerance to black flies from years of having their blood sucked, say coddling tourists is not worth the cost.

Rather, the locals offer a plethora of folk remedies to reduce the incessant buzzing, ranging from ingesting Vitamin D or garlic pills to wearing light-colored clothing and not eating chocolate before heading into the woods.

The approaches have varying degrees of success.

Healy, the writer and outdoorsman, recently was given an electronic device that emits the sound of a dragonfly, a natural black fly predator. "I used it along with a lot of bug dope," he said. "I still got eaten alive."

Some people adopt a sort of rhythm method of avoiding black flies when it's most likely they are feeding. Molloy said the bugs bite most during the mornings and the late afternoons on cloudy, windless days when the barometer is falling and the temperature is in the low 80s. The bugs are inactive at night and do not like to go indoors.

Vanselow, the black fly control expert, said the insects are attracted to carbon dioxide, so she tries to breathe downwind. "If you can breathe so your exhales go downwind from your body, it makes a big difference."

Others take a stoic approach.

"You just gotta endure," said Nelson Turcotte, a logger who stood among the pile of yellow birch and hard maple he and his brother Sylvain had cut down that day outside the town of Newcomb.