THE WILD LADIES of Thrace decided they didn't like Orpheus at all, though he was divine and a regular god of melody.So they tore his head off his shoulders, among other things, and this is supposed to illustrate the power of music because the severed head kept singing as it floated down the stream towards Lesbos.

When I first heard that myth I thought it also illustrated the force of Thracian women and the general dangers of singing.

But I accepted an invitation, all the same, to a rehearsal of the Friday Morning Music Club this week.

Men were allowed to join starting in 1965, but I knew most of the 800 club members were women.

I knew they were hard-core music types, easily inflamed by a chance comment about Gluck, and I suspected (and it is true) they take music somewhat more seriously than food, life and similar nonsense.

Byt by taking care not to hum or say anything beastly about Ives, I deemed the day would be safe enough, especially since my guide through this dangerous territory was Vivian Brown, violinist of the orchestra.

She warned me the club does not deal kindly with those who call them old ladies wheezing their way through Rossini, but here is what I found:

First, they were not all that old. Many seemed to be in their early 30s. Even the ones with gray hair were taking the last movement of the Beethoven Eighth at a speed greater than Toscanini.

"Amazingly enough, that sounds very good," said the conductor, Robert Gerle.

He said it, not I, and I was not one of those who ha-ha'ed at the little joke.

But first there was marilyn Neeley, a club member, perceeding through the Mozart B-flat concerto with a subtle adjustment to the orchestra that astounded me. Glorious, not competent, is the word for that pianist.

Gerel mentioned Needly lived with him so of course there is a rapport there. They are married and have Andrew, 6, who is patient.

He sat alone, surrounded by a sea of empty chairs at rehearsal as his mother coaxed the last nerve out of a B-flat.

Once or twice he stuck a small paw out and wiggled some small fingers (she could not see him) to show her how the legato went.

Gerle forgives any merely human disaster, but does not forgive mechanical sawing.

"Play the phrase," he cried to the orchestra, "play the phrase.

"Now when Beethoven repeats the same little motive four or eight times, it's not just to fill up the side of a disc. It's there for a reason. For emphasis..."

Or whatever. In any case, God help you if you stop concentrating on the fifth time.

Later at lunch with Brown, Gerle said he once saw Jacques Thibaud drop his bow in the middle of a concert while the orchestra sailed right along.

"He caught it between his elbow and his side and was fishing around trying to get it back in his hand. Which he did, eventually.

"After the concert he told me he had sometimes dropped a few lines of music, but never yet dropped his bow."

The cellist Casals -- to show you the general peril -- once began a concerto with a great upswing and off shot his bow into the audience. Somebody kindly handed it back and the music resumed.

But at the Friday Morning Music Club concerts there are no horror stories of the sort:

"We don't make gaffes," said a symposium of club presidents, racking their collective heads to equal the Casals mishap. "Sometimes sirens," they said.

The club is in its 94th season.

"We weren't all of us there for the founding, you know," said Brown.

The club was an important factor in establishing the National Symphony, pledging 5,000 1931-type dollars towards it.

Once the club held forth at the male Cosmos Club. Men did not let them use the main lounge, of course, and once a Cosmos committee ordered the women's pianos removed, from "any chambers" of the place. Later, more claimly, they were relegated to the Assembly Hall.

The music club was founded in October, 1886 among a few women who met in each other's homes.

They studied, as well as played for each other, and at meetings used to read articles aloud from usic journals.

Once they heard a book review in which the author took a lordly down-the-nose view towards Wagner and other Romantics.

The club went on record, at that time, as not despising Wagner and the rest.

Again, when Tchaikovsky's music was new to American audiences, the club thought it prudent to announce the composer wrote all those notes in there, so kindly do not blame the club orchestra for the sound.

Tchaikovsky is hardly throught harsh in his harmonies now, but he was difficult for Washington a few decased ago.

The club's concert at 11 a.m. next Friday will be the first orchestral offering of the new Terrace Theater at the Kennedy Center. It is free.

Every Friday, as a rule, there are free club concerts at the YWCA at 17th and K Streets NW.

Usually about 150 people hear them.

The club sponsors 600 free concerts a year in local schools, and it competitions for voice, strings, and so forth have given welcome dollars to young artists at the start of their careers.

The Washington International Competition this year will give $4,750 in awards for violin, viola and cello and an additional $1,000 for a string quartet composition.

Jessye Norman, the singer who won in 1968, is busy this year with the Boston Symphony Orchestra and the Paris Opera.

Such other winners as Robert McDonald (heard recently in a Phillips Collection recitial, a musical series founded decades ago by the club's Elmira Bier, by the way) and Evelyn Lear, now with the Metropolitan Opera, and Gil Morgenstern, Diana Steiner and about 30 others are now in concert work.

Members of the club have included a cousin of Alexander Graham Bell, who once came to lecture the club on "Sound," and Esther Ballou, the first woman composer to have her music played at the White House.

Dina Kostin is condirector of the Theater Chamber Players of the Kennedy Center. Virginia Harpham is principal second violinist with the National Symphony. Ann Schein, in addition to her own piano work, is wife of the Juilliard Quartet's Early W. Carlyss. And so on.

In the 46-piece orchestra with the Mozart (the director thinks it may be a bit strong on violins) you might notice the concertmistress, Melissa Graybeal, plays viola with the Smithsonian Chamber Players and teaches sessions at Oberlin College on instruments of past centuries.

Mary Price is another violin-viola virtuoso, and Mary Lee Esty, who plays principal second violin for the club, also makes violins.

Evelyn Elsing, a finalist in the Moscow Tchaikovsky Competition last year, plays cello, and Brigitta Gruenther, principal cellist, also plays in the Washington Bach Consort.

Jacqueline Shaffer, orchestra chairman, used to play bass with the National Orchestra of Manila, and Carolyn Kellock has no trouble playing with a blus grass band when not absorbed with Rossini. David Yaken is one of the orchestra's 10 mile members -- a student at American University and devoted to the tympani which add considerable thunder to the Beethoven.

"I try to practice two hours a day," said Brown, and some of the other players manage more. "We don't really have much time to back cookies," she said apologetically for the store-bought ones at rehearsal break.

The rehearsal was at the Bethesda United Church of Christ, with a nursery school going on outside. Occasionally mothers and tots would peer through the windrows and listen a spell to the music.

From the back, you could see past solemn Andrew instructing his mother, to the players leaning in to the scores.

A face with lines next to a face like a peach.

The plucked strings were not quite loud enough. Again, please. Ah, much better -- the plucked strings do not carry like a bowed note.

The long line of Mozart -- "please, there is no time to gradually get into the spirit; the tone and balance must be there from the first" -- and the long line of those who play music, from Orpheus on down.

Often with happier fate.