In isolated pockets across the Washington area, periodical cicadas have begun to emerge in heavy numbers, the silent beginning of an infestation of black-bodied, red-eyed insects that is going to get a lot more intense and a lot more noisy before it ends next month.

"It's happening," said Michael J. Raupp, a University of Maryland entomologist, referring to the mass emergence of the Brood X periodical cicada in the District and 15 eastern states. In the coming days, he added, "it's going to be, like, everywhere."

He spent part of Sunday night 30 feet up in a tree in University Park, watching cicada nymphs leave the soil, climb upward and molt into adulthood. He saw hundreds of the bugs on individual trees, a sure sign that the emergence is underway.

"It's definitely begun in D.C.," added Dan Century, who runs the Cicada Mania Web site (www.cicadamania.com) from Metuchen, N.J. "Within a week," he added, the insects will be "at full-blown noise levels."

Yesterday morning, at the southern end of Chevy Chase Parkway NW, it was clear that scores of cicada nymphs had crawled out of the earth during the night and perched on a bush, an oak and, in some cases, a telephone pole. One or two settled for a dandelion stalk.

By late morning, some were still molting, splitting open the back of their nymphal shells and squeezing out, leaving the husk stuck to its perch. Then they unfurled their wings, waiting for several hours on a leaf or a tree trunk before attempting flight.

As they paused, their exoskeletons darkened from off-white to black. The veins in their wings turned amber. Their eyes stayed red.

For these early risers, the open-air world was filled with danger. Some nymphs died under the wheels of passing cars. Others met their end between the jaws of a squirrel. The adults that took flight frequently caught the eye of birds that were faster, more agile and hungry.

As a species, the main survival tactic of the periodical cicada is to satisfy the hunger of predators by appearing in huge numbers. Even if many are eaten, goes the theory of predatory satiation, many will live to procreate.

As with many theories, the practice isn't so neat and tidy. Yesterday, the sparrows and other birds of Chevy Chase Parkway acted as if they had won free admission to an all-you-can-eat breakfast, snacking on cicadas with abandon. Late in the morning, things got sort of nasty.

As one cicada took what might have been its maiden flight, a bird swooped down and knocked it to the street. The bird quickly took off the insect's wings with tearing jabs of its beak -- a step that usually precedes consumption. Suddenly the bird flew away, perhaps because it had already eaten its fill, leaving the cicada to hop around on the asphalt. About thirty minutes later, another bird landed and gobbled up the insect.

Very few pedestrians appeared on Chevy Chase Parkway yesterday, and those who did were surprised at the sight of a little bush, about four feet tall, that grows next to an oak several stories high. The bush was festooned with scores of cicada husks -- brown, translucent shells that look remarkably intact considering they are empty. Atop the leaves of the bush, more than a dozen adult cicadas basked in the sun.

"Oh my gosh," marveled Elizabeth Arrott, who lives around the corner. "There are an awful lot of them."

"Wow," said Pam Joos, 35, showing the bush to her young daughter, Kate, "there is a whole bunch." Kate raised an arm into the air.

Over the telephone, amateur naturalist John Zyla was eating his heart out. He has been planning to track this year's emergence of Brood X -- the X stands for 10 under a system for naming 17-year and 13-year cicada broods devised by a federal bureaucrat -- but a business trip for his day job is taking him away from the region this week.

"This is driving me crazy," he said, listening to a description of the cicadas soaking up the sunshine. "I wish I was there."

A brood of 17-year cicadas emerges in the eastern United States nearly every summer, and Brood X is the largest, ranging across 15 states from New York to Missouri and as far south as Georgia.

In Cincinnati, another urban hub of Brood X's multi-state patch, entomologist Gene Kritsky reported yesterday that there was "nothing heavy yet." Scattered cicadas have emerged but not on the order of Michael Raupp's hundreds-per-tree observation.

"We need a big rain," Kritsky said. "That really does a lot to soften up the clay soil."

Raupp, like a surfer who has caught a wave, wasn't sounding at all anxious, calling a reporter early yesterday to announce, "They're up, dude." And they just keep coming. "We're expecting this to be another wicked night tonight."

On the Cicada Mania site, residents of the District, Northern Virginia and Silver Spring posted messages with sightings of the emergence. "Rose," of Rockville, wrote to say she watched them all day yesterday.

"They are crawling all over my hostas, daylilies and shrubs as well as up the brick facing of my townhouse, all around the door," she wrote, "which is a little freaky. I'm both horrified and fascinated!"

"Dona," of Bethesda, had posted earlier messages voicing the concern that no cicadas would grace her yard.

"I have two cicadas in my yard right now," she wrote yesterday. "One is still drying one wing, and the other just flew off. Last night after my angst at not seeing any holes, I found one adult in the front yard. Yes, I am happy."

A molting cicada leaves its split shell behind.A sparrow homes in on a slower-moving cicada. Emergence of the bugs offers birds a delectable smorgasbord.Predators abound for the newly molted cicadas: birds, squirrels, even cars.