Yearning for the one day of the year when he could break the adult pattern of navy pin stripes and emerge as something out of the ordinary, Larry Smith yesterday folded a brown beard inside his gray felt hat and fingered the corncob pipe that would complete his punk hillbilly outfit.

"I'm way past the trick-or-treat stage," Smith said. Yet he joined thousands of Washington-area adults who searched costume and novelty shops, preparing to enter the ranks of celebrants in a holiday once reserved for the under-12.

"Halloween gives you a time to release, to act silly," he said. "It gives you a chance to dress crazy, not be serious." Smith said he will don a pair of bib overalls, a flannel shirt and "dye my hair some crazy color."

The anxiety provoked by past Halloween scares, including candy that has been poisoned or otherwise tampered with, has caused a reversal of roles for the Oct. 31 holiday this year. As the grown-ups prepare for costume parties and bar-hopping revelry, many children will not enjoy the traditional trick or treating.

In the District, police and city recreation officials are asking parents to take their children to Halloween parties at the city's recreation centers as an alternative to going from door to door. And in some suburbs police have suggested early hours for those who do go out. In addition, D.C. police say they plan increased patrols in Georgetown, a popular gathering spot for adult celebrations.

The switch of emphasis from children to adults has had its effect on area costume retailers in specialty shops, department and drugstores, who said the sales of masks and wigs for adults have ballooned over the last several years, while tiny princess and goblin outfits for children have gathered dust on the shelves.

Yong Kim, who with his wife, Meranda, owns Stein's Theatrical and Dance Supply Centre in Arlington, pointed to a rack of small, red-and-black-footed jumpsuits for aspiring school-age cats and devils. They were no match for his store's huge selection of adult-size Lycra leopard suits, frothy French maid outfits and billowing harem pantaloons.

Andy La Pointe, manager of Drug Fair in Rockville's Loehmann's Plaza, agreed that "more of the adults are getting dressed up. Basically, we're not carrying as many children's costumes anymore. With all the things that have been happening with Halloween, it's been slow compared to the last two years."

"Our store is 99 and 9/10 percent adult. We rarely get a child in here," said Maye Rosenthal, an owner of Backstage Inc. on P Street NW. "They're getting ready for Georgetown, and there are a lot of private parties. I believe it's a chance for fantasy."

When Philip Andersen was growing up in Iowa, Halloween was for children. It meant trick or treating and stealing pumpkins from farmers and, once, getting stung by BB shot in the seat for "going over the wrong fence."

Yesterday at Stein's, Andersen modeled an adult-size Uncle Sam suit that he will wear on Halloween at Clyde's in Tysons Corner, where he works as a waiter.

Each year in the Washington area, Halloween comes a little closer to being as wild as Mardi Gras. Its commercial success has filled shops and wearied clerks for the past week.

"It's like a madhouse," said Linda Banks, assistant manager of the Halloween shop at Sears on Wisconsin Avenue NW. "The rush started Wednesday of last week, and Saturday was the pits. We sold over $2,400 worth of costumes and accessories just that day. It has become, to me, a second Christmas."

Kim said the weather and the calendar make a difference in Halloween sales. If the thermometer sinks before Halloween, customers want gorilla suits and heavy rubber masks. "If it's warm, we sell more, ah, exposing-type" costumes, he said.

Television, theater and politics can sway costume popularity as well, Kim said, and Stein's tries to jump on the trends by stocking up on popular accessories, such as Michael Jackson-style glitter gloves. But there was one timely demand he couldn't meet.

"I had so many requests for Mondale and Ferraro masks," but mask manufacturers couldn't mold a Ferraro face fast enough, Kim said. He said the Reagan masks -- several dozen of them at $16 and $20 each -- were all sold out.

And because many Halloween parties were scheduled for the weekend, about 1,000 Saturday customers nearly emptied Kim's costume stock, returning the outfits just in time to have them cleaned for the actual holiday.

While many customers at Stein's pay from $25 to $45 a night to rent or buy from the racks of ready-made costumes, others conjure outfits from a million ingredients -- pancake makeup, glitter hair spray, spirit gum, hanks of wiry hair, bloodstained rubber thumbs, spiked chartreuse wigs, plastic pitchforks and yards of satin, lace and feather boas.

The characters they can become are limited only by their own imaginations. "I like to do moods," said David Williams, 26, as he flexed his right hand to test a new white glove. One year, Williams said, he dressed as Melancholy. Once he was Sunshine, in thick layers of orange and yellow makeup. "Argghhh . . . . it was a mess," he recalled.

Williams said that adults need the release that Halloween provides. "You can explore other dimensions of your own personality," he said. "You can be a sicko and no one will put you down for it."