For the second time in two days, massage-parlor entrepreneur Louis Michael Parrish and his top associate were convicted by a federal jury on charges of operating what prosecutors called the largest prostitution ring in the Washington area.

Parrish, a pudgy, 32-year-old businessman known as "The Old Man," was found guilty of two counts of prostitution and two counts of interstate racketeering by the same jury which had convicted him Thursday on five related charges.

Larry J. Wadino, 31 described in court testimony as Parrish's alter ego, and business manager of Parrish's once flourishing call-girl operation, was convicted yesterday on two counts of prostitution. He had been convicted Thursday of conspiracy to commit prostitution and racketeering and prostitution.

In all, Parrish was convicted of nine out of 11 charges against him and faces a possible sentence of 45 years in prison and $50,000 in fines. Wadino, convicted of four of the five counts against him, faces 20 years in prison and $25,000 in fines.

Both men declined to speak to reporters after the verdicts were handed down at noon yesterday by a jury of 10 men and 2 women in Alexandria federal dilstrict court. The jury had deliberated two hours before returning its final verdicts in the case.

Parrish -- whose earlier image as a reclusive, gun-toting entrepreneur contrasted sharply with his easygoing, often jovial demeanor throughout the trial -- turned to special FBI agent Charles Bartles before the jury returned ands shook his hand.

"You got me," Parrish said, smiling.

Parrish, Wadino and Kathy Lynn Caldwell, 25, who ran one of Parrish's "outcall" services, were indicted Jan. 29 by a federal probe into a lucrative chain of Parrish-owned massage parlors and "outcall" masseuse dispatch services which were based in Alexandria.

On Thursday, Parrish, Wadino and Caldwell were convicted of conspiring to commit interestate prostitution and racketeering and othe charges.

(In yesterday's editions, it was incorrectly reported that Caldwell and Wadino were found guilty of racketeering, which is a separate offense under federal law.)

The indictments grew out of an ongoing federal grand jury probe into prostitution, gambling and possible political corruption in Alexandria. Prosecutors have said it is a "possibility" that Parrish will be called to testify before rumors of payoffs and protection.

Left unanswered by the three-day trial prosecutors says, is how Parrish was able to operate his parlors in Alexandria.

The Parrish jurors, who were presented explicit testimony from 13 government witnesses and cartons of evidence including Parrish's business recoreds, credit card receipts and sexual paraphernalia, were ordered not to speak to reporters by U.S. District Court Judge Oren R. Lewis.

In an unusual procedure, Lewis allowed the jury to announce verdicts on half of the counts Thursday and allowed them to return home for the night before deliberating the remaining charges. Defense attorneys objected to the move and yesterday cited newspaper accounts of the first guilty verdicts as basis for a mistrial. Lewis rejected their motions.

Lewis set sentencing for the three codefendants, who are free on personal bond, for April 13.

U.S. Attorney William B. Cummings, who prosecuted the case with assistant Henry E. HUDSON AND SPECIAL ASSISTANT Paul N. Murphy, called the Parrish trial one of the largest interstate prostitution cases ever prosecuted in Virginia.

From december 1975 until May 1978, when the FBI closed Parrish's operatons in a massive midnitht raid, Parrish employed more than 50 masseuses at time who worked out of 11 massage parlors, "outcall," dating and escort services, the prosecutors said. Several who testified against Parish earned an average of $3,000 a week by prostituting themselves, prosecutors said.

Attorneys for Parrish and his two associates called no witnesses on their behalf. Instead, they attacked the credibility of former Parrish employes who entered into plea bargains and agreed to cooperate with prosecutors by appearing before a federal grand jury.

As the story unfolded, Parrish was portrayed as a hard-driving businessman who used several pseudonyms and corporate shells to disguise his illicit activities. He kept daily work sheets which accounted for each customer and the money paid to masseuses in cash and credit cards.

The women received a percentage of the straight massage rate (from $50 to $100) and whatever tips or "grats" they could earn by offering "extras," witnesses said.

One witness testified tht Parrish planned to open an "English" (sadomasochistic) room in the basement of Bunny's massage parlor so he could have "the best damn whorehouse in Alexandria."