W. Arthur Garrity Jr., the federal judge who ordered Boston schools desegregated in a case that triggered rioting and racial turmoil, has died of cancer. He was 79.

Judge Garrity's 1974 decision that ordered students bused to achieve racial balance helped change the composition of Boston schools.

Court officials said Judge Garrity, of Wellesley, Mass., died Sept. 16 of cancer.

White parents reacted to the busing decision by hurling rocks and epithets at buses that brought black children into their neighborhoods and refusing to let their children attend black schools in minority neighborhoods.

For months, helmeted motorcycle policemen escorted the buses carrying black children into Boston's working-class white neighborhoods as hundreds of state and city police officers ringed the schools.

Judge Garrity also received death threats. In an interview in December, he said he still received letters and e-mails from the ruling's opponents.

"They send me unordered magazine subscriptions and announcements for real estate opportunities in Arizona and such," he said.

Judge Garrity began his law career as a clerk to U.S. District Judge Francis J.W. Ford from 1946 to 1947. He went on to serve as an assistant U.S. attorney from 1948 to 1950.

After practicing law in a private firm for 11 years, he returned to the federal prosecutor's office in Massachusetts in 1961, this time as U.S. attorney. His five-year tenure in that office was followed by his 1966 appointment to the federal bench.

In July, the Boston school board voted to end busing because 85 percent of the city's public school pupils are now minorities.

Judge Garrity was born in Worcester, Mass., and graduated from Holy Cross College. He received his law degree from Harvard Law School.