They insulted and antagonized the most powerful members of the Maryland House of Delegates. They breached legislative protocol by making open threats to "get even" with their opponents. They bartered votes so lrazenly they were chastised publicly by the speaker of the House.

In their unsuccessful attempt today to revive a proposal for $20 million in state funds to build a convention center near the Capital Centre arena in Largo, the Prince George's County delegation provided what many other legislators considered a lesson on how not to get your way in Annapolis.

Leaders of the Prince George's delegation even upset some of their own followers. "They lost any confidence I had in them," said Del. Frank B. Pesci (D-Prince George's). "They went to the mat for the convention center and lost. You don't pull out all the stops - the insults, the calumny - and then lose."

When it was all over today - after an angry House beat down (by a 71-to-57 vote) the county's attempt to override a committee vote against a $20 million state bond issue for the convention center, some Prince George's delegates apparently still had not learned their lesson.

"We'll send that guy back plucking chickens," vowed Del. Gerard F. Devlin (D-Prince George's) in reference to Del. John R. Hargreave breeder who is chairman of the powerful House Appropriations Committee. All Prince George's requests for state money must be approved by Hargeaves' committee.

On Friday, that committee over-whelmingly had rejected the $20 million bond issue for the convention center. Today, Prince George's delegates had attempted to end-run the committee system by getting the full house to override the Appropriations vote. That, too, is considered a breach of protocol that almost never works and didn't work today.

Seeking support for their maneuver, county delegates sought vote-trading deals with other members on such issues as raising the state's drinking age, constructing a prison in Baltimore, increasing state aid to Ocean City's Convention Hall, and prohibiting fees for telephoning directory assistance.

Prince George's delegates had been all over the House floor in full public view for the past few days in search of the 72 votes necessary for their bill.

Vote-trading is common in Annapolis but this apparently went beyond the tolerance level.

"Sure, votes are traded," said Del. John Hanson Briscoe (D-St. Mary's), speaker of the House.

When the entire Black Caucus voted in favor of the convention center, the chairman, Del. Arthur G. Murphy Sr. (D-Baltimore), denied that there was a trade. But he did say that he was "very optimistic" that the Prince George's delegation would support the caucus in opposing the use of the Continental Can building as a prison site.

Del. George J. Santoni (D-Baltimore City) received a sudden boost of Prince George's votes for his bid to defeat an unfavorable committee report on raising the state drinking age to 19 years old. The agreement with Prince George's, said another supporter Del. Michael J. Wagner Sr., was made because "we were bothe fighting the same issue" of overriding a committee decision. Despite their mutual support pact both efforts failed.

"But it's usually done a lot more subtly. The trade-offs reached their peak with the convention issue and that behavior was very offensive to a number of legislators."

Briscoe rarely criticizes his colleagues publicly, but with the vote-trading and the insults from Prince George's County delegates, he said things had "gone too far."

It was clear that the wheeling and dealing had not produced the required number of votes. So Prince George's delegates began to speak from the floor on the issue, directing their criticism at the Appropriations Committee and then the entire leadership.

Del. Robert Redding (D-Prince George's) said that "when you deny debate, you deny integrity. When you enlist powerful outsiders . . . the system lacks integrity and this becomes tyranny.

"When a handful of very powerful people do anything they want whenever they want to, then we no longer have any need of them," he said.

Then came the wrath of the leadership. "I have been personally attacked, unjustly accused on the floor," said Del. John S. Arnick (D-Baltimore County), the majority leader and chairman of a major committee.

"I resent it and I will continue to resent it," said Chairman Hargreaves. "My integrity has never been impugned before in business or the legislature. My memory," Hargreaves warned, "is that of an elephant."

Del. Robert A. Jacques (D-Montgmery) challenged Redding's hints of "powerful outsiders" involved in the convention center defeat and said that it was not the leadership or anyone else in the Assembly but "others who we all well know" who were the powerful outsiders.

This was a reference to Prince George's County lawyer and political leader Peter F. O'Malley, father of the convention center proposal. The center was to be developed and operated by O'Malley's law client, William Levitt Jr., who would in turn donate the land and $13 million for construction of the center.

All of the leadership voted against the Prince George's bill today, including Del. John W. Wolfgang, the only Prince George's delegate who heads a committee. Del. Pesci ultimately abstained.

Del. Kay Bienen (D-Prince George's) voted with her delegation but said she was "disappointed . . . You don't have to be vicious and attack the leadership to win your point," she said. "In fact, that's how you lose."

The Prince George's leadership - especially Del. John Garrity and Devlin - raised the spector of continued antagonism on the House floor because of the tremendous defeat. Garrity particularly was angry with the Montgomery County delegates who he said "sold out to the District of Columbia by voting against our convention center in favor of the District's."

"We must keep our professonal judgment but it's difficult to rationalize a defeat by your neighbors," he said. "It's hard to keep from being acrimonious."

Devlin, on the other hand, lunched with Baltimore City delegation chairman Paul E. Weisengoff, who delivered 27 votes for Prince George's. That was the result of a year-old deal for the county's support of Baltimore's convention center. Weisengoff was overheard giving instruction to Devlin on how to save your votes "for the best shot."

Devlin and his colleague Garrity supported the convention center to the end and predicted that the "county will become another Northeast Washington" without it. "It may be the unraveling of the county, without some economic turn we'll become a Baltimore City without a downtown."