OXFORD, Miss. —fUPD— Negro student James H. Meredith again found himself taunted Wednesday night at the University of Mississippi cafeteria.About 200 students beat on their trays and glasses with silverware when Meredith entered the cafeteria accompanied by his ever-present escort of federal marshals. The 29-year-old Air Force veteran smiled at the noisy I greeting and sat down, touching ' off a walkout by students at surrounding tables.It was the third straight night of demonstrations at the cafeteriafollowing a long lull. Many students jeered and left the cafeteria when Meredith entered Monday and Tuesday nights. They shouted, “ignore the nigger with vigor.”Campus sources said the students are protesting what tney regard as a publicity stunt by Meredith—his statement Monday that he would not register for the next semester unless “definite and positive changes” are made at the university. They said students felt that campus tension had eased and Meredith’s presence at “Ole Miss” was no longer of national interest until his statement rekindled the issue.Rep. Tom Abernethy, D-Miss., in Washington, Wednesday accused Atty. Gen. Robert F. Kennedyof collaborating with Meredith onthe statement.“T h i n g s were becoming too quiet down there and evidently the attorney general felt that in order to squeeze a little more political mileage out of the situation, it was necessary that he and Meredith do something to get the whole prostrate university back in the limelight,” said Abernethy.