Donna Caponi Young birdied the last hole for a 68 that the first-round record for the U.S. Women's Open and gave her a two shot lead yesterday.

At 70 were defending champion Hollis Stacy, second-year pro Vicki Fergon and Alexandra Reinhardt.

It was a hot, horribly muggy day, here in the Indiana capital where, as the song says, and this week's weather forecast agrees, it never rains in the summertime. Stacy was off to a splendid start, one under par, and in excellent position to stay that way as she played the par 3, 158-yard sixth hole. The 24-year-old former National Junior champion fron Savannah, Ga., reached the green from the tee, 18 to 20 feet from the pin. Her first putt was to within two feet of the cup. Everything was lovely until the little bee bumbled into the act.

"I kept brushing it away," Stacy recalled, "but it just kept staying there in back of me, dancing around. I brushed it away again. It still kept coming back. That particular green was really fast, but not as fast as I played it I rushed the putt, pulled it, for three putts and a bogiy."

Her inability to float like a butterfly eventually cost Stacy sole possession of the lead. She saved par with an 18-foot putt on the next hole to fall back one over before rallying with birdies on the last two holes by sinking putts of six and 18 feet Stacy led throughout last year's Open near Minneapolis to defeat Nancy Lopez by two strokes. Lopez led early yesterday, at two under, then came in at 71 along with Janet Coles and amateurs Cynthia Hill and Noreen Ulhlein. One of day's most interesting scores was the 74 trrned in by Mickey Wright. The 42-year-old winner of 1958, 1958, 1961 and 1964 Opens was tied with Betsy Rawls for the most such victories.

Fergon, a slender brunette from Palm Springs, Calif., birdied the last hole to join Stacy on the lead.

"I was just trying to play it safe, by that time," Fergon confessed, "and I hit a two-iron off the tee very poorly. But I came back with a good wedge shot from about 120 yards and made the 12-foot putt. I missed only three greens, using my three-wood off lots of tees."

Fergon finished first in the LGPA's qualifying school competition last summer, with Lopez third. Their careers have gone sharply different directions since, Lopez earning more than $135,000 on the tour this season while $460 had been Fergon's biggest payday until Sunday.

"I was tied for the lead, seven under, on the eighth hole of the third round (of the tournament at Dublin, Ohio) last week," she said. "Then I guess I got a little nervous and went into the water, for a triple bogey. Actually, I didn't know I was tied for the lead, but being nervous has been one of my problems. I took the winter off to work and to think. I know I have the talent. I can do it. Maybe it might take me a little longer to prove it. But I'm here to stay. This is what I want to do."

Ulhelin, Coles and Hill joined Lopez one shot off the leaders by playing steady if unspectacular over the 6,155-yard course. Coles, of Carmel, Clif., matched par perfectly with 35-36. Ulhlein, from Barrington, R.I., and Hill, playing out of Colorado Springs, are members of the U.S. Curtis Cup squad.