Mary T. Meagher won her second event in Olympic gold metal bettering time tonight, grabbing the 100-meter butterfly in 59.41. Earlier in the U.S. National Swimming Championships, the 15-year-old set a world record in the 200-butterfly event.

In the men's 100-butterfly, six of the qualifiers were under the gold medal time in Moscow. William Paulus was the winner in 54.34.

Mike Bruner added the 1,500-meter freestyle crown to an earlier victory in the 400 and a second-place finish in the 800 freestyle and 200-meter butterfly.Bruner covered the metric mile in 15:19.8 -- averaging 1:01 for the 30-length swim of the 50-meter pool.

Second place went to Dave Sims in 15:25.92. The world record and gold medal winning time in Moscow was 14:58.27 by Vladimir Salnikov.

Betsy Rapp, 20 of Starlit Aquatic Club, Fairfax, Va., will join her sisten, Susan, 15, in international competition in Hawaii Aug. 11-14. Betsy was 16th in the 100-meter butterfly in 1:03.31.

The international meet will feature teams which boycotted the Moscow Olympics and other nations.Another Starlit swimmer, Clay Britt, 18, was selected following his fourth-place finish in the 100-meter backstroke.

Other swimmers from the Washington, D. C., area competing on the final day were Jenny Rapp, 17, of Starlit and Simone Kusseling of Solotar Swim Team, Annadale, Va., in the 100-meter butterfly. Rapp finished 34th in 1:04.08 and Kusseling 61st in 1:05.46.