Mary Conroy, widow of the late Bowie Sen. Edward T. Conroy, said yesterday that she has changed her mind about running for the Maryland House of Delegates and will officially drop out of the race today.

Conroy, 50, was appointed by Gov. Harry Hughes on June 24 to fill out the remaining months of her husband's term. Democrat Edward Conroy, a 20-year veteran of the Maryland statehouse, died in May of cancer.

Mary Conroy said she changed her mind about running for office because "I just have so much to do with my family."

According to Democratic sources in Prince George's County, Conroy's decision to drop out came after discussions with Steny H. Hoyer, the area's congressman, Leo Green, the Bowie candidate for the state Senate, and state Sen. Thomas V. "Mike" Miller, all of whom talked to her about the possibility of a county or state job.

"She had very mixed feelings about it running ," said one Democrat familiar with the discussions. "She was concerned about security for her family and the three men committed to her" without promising a specific county or state positions.

Miller, contacted yesterday, said, "I think we just convinced her that she's a good friend and an old friend and that the Democrats wanted her to continue to serve in public office."

Conroy's decision is likely to help the three incumbents, Gerard Devlin, Joan Pitkin and Charles J. Ryan, who now face a challenge in the September 14 primary only from former assistant sheriff James Hubbard.

One Republican, Sharon Metcalfe, also is running for one of the three delegate seats, but because Bowie is overwhelmingly Democratic, is not expected to pose a serious challenge.