Jerry Scheer watched the almond-skinned belly dancer gyrate to a slow, sensuous Arab melody. As he watched her legs, covered in silver mesh stockings, glint in and out of swaying folds of white chiffon and gold lame, her golden girdle, weighted with beads and pearls, slipped below her navel. Depending on the eye of the beholder, the dancer was veiled in diaphonous fabrics or she was nearly naked.

She zeroed in on the doctor celebrating his 50th birthday. "I just love mature men," she whispered, as she also kept smiling at Scheer. He smiled back, and as she passed him, he thought he heard her whisper, "Jerry, don't you remember me?"

The applause, the whistling and the shouting still swirled about the room, when the dancer approached Scheer and asked, this time loud and clear, "Jerry, don't you remember me?"

He didn't.

"It's your old friend, Pam Jones."

Scheer couldn't believe it. Pamela Jones? Ten years ago, he had been her boss, working with her five days a week at the National Institutes of Health. He knew her as a computer programmer and a mother of two sons, a woman married to the same man for years. Jones explained that she still works at NIH (she is now a GS13), that she still is, after 21 years, happily married to Ken Jones, also an NIH computer specialist, and that one of their sons is in the Army. Pam Jones is still the same strait-laced bureaucrat she was years ago. All that aside, she's been belly dancing for almost a decade. Even when she worked for Scheer, she was taking lessons and dancing at clubs, private parties like the doctor's birthday bash, Arab christenings and weddings.

"At NIH, I don't run around saying, 'I am a belly dancer at night,'" she says, "but I don't hide it either. I like to keep my two lives separate."

During her days at Walter Johnson High School in Bethesda, Jones had yearned to be a ballerina. "In the '50s, daddies' little girls studied ballet and wanted to be Shirley Temple," she says. "Then the little girls got married and bought a house in the suburbs."

In Pam's case, her parents talked her out of seeking a career in ballet, and she signed up for an experimental course in computers. "I was good in math, logic and puzzles," she says. "A dancer thinks of formations and numbers." After gradua tion, she went to work at NIH, where she met her husband. When each of her sons was born she stayed home only six months and then went back to work -- "work work," as she calls her 9-to-5 job, in contrast to her dancing, which she calls just "work."

"It was all work and no play till I was 30," she says of her early ambition to excel at her job. "But I never got dancing out of my system. With my children grown, I studied Middle East dance. After three years of study I started dancing professionally. But if somebody told me then that I'd be still belly dancing now, at the age of 40, I would have said, 'You are crazy.'"

Looking back, she says, her parents were right. "You can't make a steady living as a dancer. As a single person you can do it, and live out of a suitcase. But I wanted a family."

Her minimum charge for dancing is $50, but for a long evening engagement in a club or at a private party she earns as much as $200, plus tips. She is a star performer at Eastern Onion, a singing telegram company, earning about $30 of the $80 charged for "a bellygram"--which includes her 6 1/2-minute dance routine introduced by a singing messenger and accompanied by music from a tape recorder.

The fees are modest considering her costs. A moderately priced costume costs $500, and costumes tear. Jones designs and sews all her dancing attire, combinations of gold brocade, scarlet satin and white chiffon, and embroiders them with meticulous beadwork. To complete one outfit takes her as much as 200 hours, and she has eight in her wardrobe.

Pam's husband, Ken, was uncomfortable when his wife first started belly dancing. "But she did so well," he says. "I couldn't say no. She is a performer. She is another person when she dances. She practices an awful lot. She doesn't go halfway in anything. She is a Virgo --methodical."

Says Pam, "I am lucky to have a husband who is proud of me. We have a lot of trust in each other. He knows I am not after other men. He does his golf, I do my dancing. We allow each other to express ourselves."

The secret of a successful double life is organization, Pam Jones says. "I like keeping busy," she says. "I am a fanatic housecleaner. I iron. I wash windows and floors. We don't have a housecleaner, because nobody could live up to my expectations.

I am a perfectionist. I cook his meals and we go out one evening a week, usually Tuesday.

"I've got to keep my government job. I couldn't make a living as a dancer. If I broke a leg, I'd have to have something to rely on . . . I live on my government salary. My belly dancing income goes for an extra car, vacations--the luxuries of life. It comes in and it goes out.

"I love my dancing best. I am happiest when I dance because it is an expression of myself. I am respected in my job and get merit awards. But when I dance, it's me. I enjoy my government job. But it's all men tal. I am a physical person.

"I should have been a star. Nobody knows who I am."