Diffuse August sunlight filters through a blanket of mist hanging over the Beaverkill River. The verdant Catskill Mountains are muted in the haze; the air seems almost palpable.

Even the swallows appear reluctant to slice through the thick, humid air to intercept stray mayflies rising off the surface.

Most of the anglers have gone into estivation, their fly rods packed away until the blizzard-like mayfly hatches return next spring. Others are holed up at the Antrim, the watering hole for generations of Beaverkill fly fishermen, waiting for the onslaught of the evening rise.

Those few who do probe the summer waters of America's most famous trout stream under the broiling mid-day sun seem mostly to be trying to while away their time, trying to speed up the arrival of evening.

The rivers are low in the Catskills. The Beaverkill's channel has shrunken, its flow whithered to a mere trickle compared to the boisterous spring currents.

The trout, as every summer, are laboring.

Temperatures in parts of the lower Beaverkill have reached the 70s. Russell Fieldhouse, regional fisheries manager with the New York Department of Environmental Conservation, says the river has been known to reach 78 degrees by late summer when droughts are intensified by unusually hot weather.

These are worthy and willing adversaries for the fly fisher's offerings. And so are still other trout responding to summer's heat by gravitating to the shoreline. Here they lay claim to a shaded reach of water and patrol it like a jealous baron, driving out upstart young trout with a swift nudge of their snout. Both types of fish -- those in the riffles and those along the shaded banks -- will feed even during the hottest summer days.

The trout along the banks are attracted by the shade, but also by terrestrial insects the land provides during summer. Dropping McMurray Ants, Drowe Beetles, and Letort Crickets along the banks of Gairns and Barnhardts pools with a light splat, brings huge v-wakes arrowing to the fly as hefty browns zoom in to investigate the noise.

One pulls back gently on such fish, for they could well be heavier than the one- or two-pound tippet. The fish wallow briefly in the shallows, set off on a hard run, then leap wildly across the river's surface.

Covering ground, one discovers, is the secret with this technique. By dropping the bug two feet or so upstream on each successive cast, a good number of husky browns are enticed even during the hazy-sun hours.

Galen Wilkins, of Binghamton, N.Y., has perfected the simples and most effective fly for probing the Beaverkill's riffles during hot midday hours. Dub a thick body of olive or brown rabbit fur on a size 16-20 dry fly hook. Then tie a small bunch of deer hair flat over top as a downwing, behind the eye of the hook. This fly imitates caddis and grasshoppers, both prime summer trout food on the Beaverkill.

Wilkins drifts his fly over any rises he detects, but also uses it for blind probing of the riffles. Such blind fishing is all but useless in most Catskill trout streams, where, just as in Virginia and Maryland, fish are stocked before the opener and largely depleted by this late date. It's even likely to be a waste of time on most stretches of the Beaverkill.

But on the two Special Fishing Areas near Roscoe, no-kill regulations have created such a superb fishery you can cast just about anywhere where it looks like a trout should be and find one there. Chances are good, in fact, that instead of one fish you'll find two, three, or four trout -- fat, holdover browns that are eager to inspect your offering.

About 10 percent of the trout in the no-kill waters are wild fish, but the others are holdovers that grow extremely wise with the steady procession of flies drifted over them on a daily basis.

At no time is the success of no-kill regulations on the Beaverkill more apparent than when a heavy hatch comes off the water. In spring this happens just about every day from mid-morning to late afternoon. In summer it occurs at duck, when cool evening air breathes new life into the river.

The evening feeding orgy starts with a bang. Water that seemed dead an hour before twilight suddenly comes alive with concentric waves from trout snouts sipping in a profusion of insects.

Most cherished of all by the dusk-feeding trout are the tiny rust-bodied Baetis spinners. They swarm over the water in daily mating rituals, then fall spent to the stream. The trout gobble them like candy.

Though a No. 26 fly would be most accurate, the fish become rather indiscriminate at this time and the bigger bite of a No. 20 or 22 spinner pattern is worth having.

The Beaverkill is probably closer than you think. From Washington it's a seven hour drive via Rte. I-81 and New York Rte. 17. Motels, inns, campsites and restaurants are available at Roscoe, a town that lives and breathes trout fishing. Three-day New York fishing licenses sell for $5.50. Webb said, "and I did pretty well with it last week."

After winning the Maryland junior title, he placed third Thursday with a 76 in the Kiwanis junior championship at Evergreen.

"I wasn't as psyched up for the tournament as I should have been," he said at the Kiwanis tourney. "This one was sort of a letdown after winning the state on Monday."

Heintzelman beat Baltimore's Mike McShane and Congressional's Matty Fitzgerald, both by 3-1 scores, to win the Maryland championship. He shot poorly on Nos. 9 through 13, with three bogeys and a double bogey. "I couldn't drop a putt to save my life," he said.

Heintzelman built a sizable lead on the front nine and held on to win when Fitzgerald bogeyed the 17th. Heintzelman finished the afternoon with a four-over-par 74.

He shot some of his better rounds of golf earlier this summer when he reached the quarterfinals of the U.S. Junior championships in San Diego.

"I finally got a little recognition when I beat Nate Crosby, Bing's son, in that tournament," he said. "I had a lot of fun in California and met a lot of girls while I was on the course practicing. Some of them wrote and we keep in contact."

Heintzelman said he won't turn professional until he finishes college.Golf coaches at Louisiana State, Florida, Georgia, North Carolina, South Carolina and Virginia Tech have offered full scholarships.

The colleges became interested two years ago when the Walt Whitman golf team, led by sophomore Heintzelman, won the state high school tournament. But last year the team didn't qualify for the tournament.

"We'll have a pretty good team this year. I'm really looking forward to winning the state again after last year turned out so bad."

The only distraction from his team should be the Orange Bowl Christmas tournament in Florida. He then plans to play more national junior tourneys next summer.