One mother walks into Courtroom 202 every morning, takes a seat behind the defense table where her son sits, then puts on her glasses.

The other has, in effect, been banned from the trial that began last week in Prince George's County Circuit Court.

Instead of listening to accounts of cocaine use by her deceased son and his close friend, this second mother has continued the forceful speeches against peer pressure and drug abuse that have brought her a sort of celebrity-mother status.

In one sense, the drug distribution trial of Brian Lee Tribble, accused of supplying the cocaine that killed basketball star Len Bias last June, is also a story about two mothers coping with the public disgrace of their families and destruction of their sons' reputations.

For Loretta Tribble, a pleasant-faced woman with graying hair, the courtroom experience has been at times numbing, at times infuriating, said Thomas C. Morrow, Brian Tribble's defense attorney.

"How can I feel better?" Loretta Tribble shouted in response to reporters' questions as she left the courthouse in Upper Marlboro this week. "My son's shanghaied."

"She's a woman of very intense loyalty," Morrow said yesterday. "She takes everything personally. She doesn't like to hear lies about her son."

For Lonise Bias, information about the trial -- prosecutors' charges that her son was "a courtesy middleman" for cocaine deals and testimony that he spent his last hours with friends, snorting from one-third to one-half of a cup of cocaine -- has come to her secondhand from the family's attorney, Wayne Curry.

Because Lonise Bias was subpoenaed by defense lawyers as a witness, she was not allowed to be in the courtroom to watch the trial. The defense rested yesterday, however, without calling her to testify.

"They never intended to call her," Curry said, adding that defense attorneys simply didn't want Lonise Bias sitting in the courtroom because her presence might create sympathy for her and hostility against Tribble.

So Lonise Bias kept busy. On Thursday night, she was a guest speaker at a convocation for graduating seniors at Northwestern High School in Hyattsville, Len Bias' alma mater, where her younger son, Jay, is a student.

According to 12th grade administrator Ron Anderson, "the senior class asked for her . . . . It was almost, to be quite honest, like a revival. I think I heard a few 'amens.' " Bias made no reference to the trial, except to say she didn't care "about what is happening in Upper Marlboro," Anderson said.

Friday night found Bias at a "Rock Against Drugs" concert in Woodbridge. Monday night, she spoke in Syracuse, N.Y., at a meeting of BIAS (Blacks Interested in Achieving Success), a high school group formed after her son's death last June 19.

Meanwhile, in Courtroom 202 in Upper Marlboro, the highly charged atmosphere that had surrounded the aftermath of Bias' death and last summer's grand jury proceedings had subsided by the second week of Tribble's trial.

Most of the people who passed through the metal detector installed outside the courtroom for this case were reporters or courtroom artists. Outside on the broad stone steps, photographers and camera technicians lounged, some of them in folding beach chairs and with books in their hands, waiting for the appearance of Tribble or another principal character in the trial.

In the buttercup-yellow and oak-paneled courtroom, a clean-shaven Tribble looked alert and interested but otherwise impassive as he listened to the proceedings. Each day, he wore a dark gray suit, a crisp white shirt and, yesterday, a scarlet tie. During breaks, he would often sit beside his mother and talk to her quietly, the affection between them obvious.

As the days of the trial passed, Loretta Tribble, who has been known for her outspokenness about her son's treatment in the case, became increasingly quiet. "I'm under too much pressure to talk today," she said yesterday, the last day of testimony.

For courtroom spectator Lola Washington of Capitol Heights, a retired federal government employe, the emotional turmoil of the two mothers, one present and one absent, has been a constant thought. She has six children herself.

"I feel sorry for both of them," said Washington, who is not acquainted with either family. "I'm a mother, and it's not so hard to put yourself in their place. No matter how your child turns out to be, no matter what people might say about him, he's still your child and you stand by him."