"Sine die" day in the Maryland General Assembly is always a time for mixed feelings: elation, sadness, nostalgia. Today, all those feelings were a little bit stronger than usual as the legislature concluded its four-year term and collectively realized that many of its 188 members would not be back.

Every four years, the legislature suffers an attrition rate of 30 to 40 percent as members retire or are defeated for reelection, and this year is expected to be no different. Many legislators are seeking higher office -- Congress, county executive, and in the cases of some House members, the state Senate -- and some are retiring.

The changes will be especially striking in the Montgomery County delegations to the assembly, where two members are running for Congress, a third is competing for county executive and a number of delegates are running for state Senate.

For those legislators, the inevitable nostalgia was mixed with an eagerness to hit the campaign trail in earnest.

"I'm ready for the new adventure," said Del. Constance Morella, a Montgomery County Republican who is running for Congress in the 8th District, where an open seat was created when Democratic Rep. Michael D. Barnes decided to make a bid for U.S. Senate. "I'm sad, but it's a healthy nostalgia."

State Sen. Stewart Bainum Jr., who is running for the Democratic nomination for Barnes' seat, begins his campaign this week after getting a heavy dose of publicity in his final days as a state legislator.

On Saturday, Bainum's effort to strip the Burning Tree Club of its state tax break because it discriminates against women was rewarded with passage of legislation he had sought for several years. And Bainum was behind an effort to force state officials to disclose whether they benefited from inside knowledge before last spring's savings and loan crisis.

Another Montgomery Democrat, state Sen. Sidney Kramer, will trade in the sometimes divisive fiscal battles he has fought as head of the Senate delegation for what is expected to be a bitter primary campaign for county executive against County Council member David Scull.

"I have mixed emotions," said Kramer. "I've enjoyed my time, but it's time to move on. It's my intention to get back and start working" on the campaign Tuesday.

Among those leaving voluntarily is state Sen. Joseph Long from the Eastern Shore, who reluctantly decided after spending the last 24 winters in Annapolis that he would prefer to spend the winter of 1987 in Florida watching baseball spring training and reminiscing about his days as a semipro player.

His voice choking and tears welling in his eyes, Long said in his valedictory speech last week that he "would treasure this association forever."

For two Democratic Montgomery County delegates running against each other for a state Senate seat, the final day brought not nostalgia, but a continuation of their political guerrilla war that has lasted throughout the session.

Del. Diane Kirchenbauer was actively lobbying against a politically sensitive bill on day care center regulations that happened to be sponsored by her arch-rival, Del. Ida Ruben.

"What can I say?" said Kirchenbauer. "I don't think the bill is a good bill, and there are a number of other people who think so, too."

When Kirchenbauer was not trying to derail Ruben's bill, she was lobbying hard on one of her own. Oddly enough, the Kirchenbauer bill also dealt with day care center regulations.

On the last day of the 90-day session, some bills that have languished for weeks suddenly sprout wings, and some bills that have languished for weeks get "lost."

As Ruben, one of many veteran House members serving their last day as delegates, said this afternoon: "Everything is either greased and gone or dead."

Among the measures "greased" was one creating a "legal mutual liability insurance society of Maryland," to provide legal malpractice insurance converage for lawyers.

The measure, S.B. 753, had been killed twice by a Senate committee, and the House companion measure had died once. But once the legislature had enacted controversial legislation to limit the cost of malpractice insurance for doctors -- there are none in the legislature -- it turned its attention to the lawyers, who are well represented here.

The bill was enacted tonight after Senate President Melvin A. Steinberg (D-Baltimore County) -- who like House Speaker Benjamin L. Cardin (D-Baltimore) is a lawyer -- suspended the rules earlier in the day to permit quick final passage.

Other bills were not so fortunate, however. Among them was one introduced by Sen. Howard A. Denis (R-Montgomery County) intended to abolish a state agency that, according to a special audit in January, is a waste of taxpayers' money.

Denis' bill would have abolished the State Permit Coordinating Council and the job of its director, Francis (Frank) J. Aluisi, who is paid $42,000 a year.

But on the final day of the 1986 session, Denis' bill was "lost" in the House Economic Matters Committee, according to the panel's vice chairman, Del. Casper Taylor (D-Allegany). "We can't find the bill," said Taylor. Some cynics in the legislature suggested that the bill was conveniently lost by the committee chairman, Prince George's County Del. Frederick C. Rummage, a political ally of Aluisi.

"It's hard for me to believe it's a coincidence the bill can't be found," said Denis. "Is there a lost-and-found desk around here?"

One item that did turn up today, just in time for the 1986 session, was the "Ethics Guide" published for the 188 members of the General Assembly by the legislature's Ethics Committee.

In a cover letter that went to all legislators, the cochairmen of the committee urged their colleagues "to refer to the Ethics Guide to update their general understanding of ethics requirements as the session concludes.