It has been business as usual in Prince George's County politics these past few weeks, as members of the county delegation to Annapolis have worked behind the scenes to select a new delegate for the legislative district of Bowie and Greenbelt before the seat of Del. Gerard Devlin is even officially vacant.

The district's state senator, Bowie attorney Leo Green, anxious to dispel any notion of back-room dealing, held his own hearing in Glenn Dale last week to review candidates interested in replacing Devlin. Devlin will resign from his legislative seat to accept a judicial appointment this month.

But the Democratic leadership in the county has decided to award the seat to Mary Conroy of Bowie, the widow of former state senator Edward T. Conroy. Mary Conroy filled her husband's seat for six months in 1982 and since last year has been a member of the county Board of License Commissioners, which oversees liquor licensing.

Those who have been locked out of such deals in the past -- including former state senator Tommie Broadwater, who wanted a hand in choosing his own successor in 1983, and Muriel Weidenfeld, a Greenbelt political activist who wanted an Orphans' Court judgeship last year -- have complained bitterly and publicly about the Democratic selection process.

This year, the power brokers set the wheels in motion to select Devlin's replacement long before April, when Gov. Harry Hughes appointed him to a District Court judgeship.

Even as he was arranging for the hearing last week, Green acknowledged that Conroy is the name he is likely to recommend to the Democratic State Central Committee, which has the constitutional responsibility to fill midterm vacancies. An official central committee hearing on the Devlin vacancy has been set for May 20.

But the committee operates in Prince George's County largely at the behest of the senators, and powerful state Sen. Thomas V. Mike Miller Jr., a master of the artfully cut deal, has said that Conroy "stands head and shoulders above anybody who stands in competition for the seat."

Conroy was among a half-dozen candidates and 40 spectators at last week's hearing, where Green, Del. Charles J. Ryan and two members of the central committee from the 23rd District listened to testimony.

Conroy, who spoke briefly, brought several supporters to testify on her behalf. One was former county executive Winfield F. Kelly, who said: "There's a time and there's a place for everybody . . . . This is Mary's time."

Conroy reminded the legislators that she has been active as a Democrat for more than 30 years, serving as a precinct organizer for presidential candidates dating to John F. Kennedy. She handed out her resume and sat down. No one had any questions.

Other applicants for the post who spoke were Edith Booker, a Seabrook resident who is a state personnel administrator, has a PhD in botany and works during the General Assembly as a reading clerk in the House of Delegates; Al James Golato, a public relations manager and former school board member; Harvey Geller, a retiree and University of Maryland graduate student; school board member Leslie Kramer, and businessman Bernie Osterman, who owns a diner and lives in Seabrook.

All except Conroy hinted at, but did not address directly, the possibility that the selection had already been determined. Golato and Kramer said they had planned to run for the seat this year in any case and thought it would help to run on a ticket as an incumbent.

But Geller was given an ovation when he said: "I know I'm not a politician. I can't campaign. So I promise now that if I'm selected for the position I won't run in November."

Some Democratic Party workers living in the northern end of the 23rd District, which includes Lanham and Seabrook, have been critical of the process during the past several weeks, in part because Green and the three other delegates live in the Bowie area.

At the hearing, Kramer, who is from Greenbelt, made a point of saying that she can get along with people from Bowie. Booker, who is black, said that the four white representatives do not adequately represent the district.

The 2 1/2-hour hearing, however, went smoothly until the end, when Joyce Shycoff, a precinct organizer and Bowie resident who works on Capitol Hill as a secretary to Rep. Morris K. Udall (D-Ariz.), abruptly short-circuited some of the conviviality to criticize the selection process.

"We're asked to sit idly by while a few select, powerful few . . . decide who will govern us," she said. "I'm not here to condemn the reported choice, but I do question the rationale . . . that the widow of an officeholder automatically becomes the prime choice."

Many Democrats in the county, she said, "are intimidated by the inner circle." Young people "are registering with the other party while we sit here processing the same old bloodlines," she contended.

Green defended the decision to hold his hearing, saying that the central committee was waiting for a recommendation from him and that he wanted to hear from everyone himself.

"Mary Conroy might have a lock on it," Green said, "but you have to go through a process."

The state central committee chairman, Del. Gary Alexander, said he will not take a position on the matter "until somebody stands up in front of me and tells me what the consensus is."