The D.C. Statehood Party's possible choices for a successor to the late City Council member Julius Hobson Sr. Narowed sharply yesterday, as Hobson's wife Tina declared her interest in filling the vacancy temporarily and Hobson's son Julius Jr., dropped out of the running.

At the same time, Hilda Mason, a school board member also mentioned as a replacement for Hobson, who died last Wednesday, said she would not challenge Mrs. Hobson as the party's choice to succeed Hobson until a special citywide election is held July 19.

As a result, it appeared likely yesterdat that Mrs. Hobson, her husband's choice to succeed him as at-large Council member, had emerged as the front-runner to be selected by the party 's 23-member central committee to serve in Hobson's place until after the July 19 election.

Mrs. Hobson, a 47-year-old energy conservation director for the Federal Energy Administration, said in an interview yesterday, however, that she does not plan to run in the special election that will choose someone to complete the remaining 18 months of her husband's four-year term.

"I never made a commitment to run for the position. He never asked that. He never intended that," she said.

The only other person regarded seriously as a possible successor is party chairperson Josephine (Jo) Butler. Butler could not be reached for comment yesterday, but last week she wanted to be Hobson's replacement.

The withdrawal of Hobson Jr., who had declared his candidacy on Thursday by saying that he felt an "obligation to pursue the seat," surprised many members of the party central committee who were interviewed yesterday.

Hobson Jr., a member of the D.C. school board, would not elaborate on his decision. "I can't say why. It's very personal," he said in a telephone interview. "There are a lot of things that have happened since last week and I can't handle it."

Hobson Jr. reiterated his intention not to run for any public office at the expiration of his present school board term at the end of this year.

The party central committee plans to meet over the weekend to make its choice of a successor, which by law must be done within 30 days-of declaration of a vacancy.

Several central committee members interviewed said Mrs. Hobson's desire to fill the post only on a temporary basis might create obstacles to her selection.

Party members had hoped to use the interim period in office to boost the candidacy of the party's choice in the special election, which will be open to Republican and independent candidates as well. Under the law, Democrats already hold their maximum possible number of at-large seats - two.

Selecting someone to act merely as a caretaker on the Council could be politically harmful, these party members said privately.