As of Wednesday, Dec. 14, the Massachusetts Lottery will launch a new way for residents to play the popular Keno game.

Keno Bonus is the new and improved form of Keno, a popular Lottery game played by placing a bet, picking numbers and matching them to randomly selected numbers chosen by a computer.

As of the official launch date, players will have the opportunity to double their wager, making them eligible for Keno Bonus. A bonus number will be displayed on the computer screen, and players multiply their winnings by that amount if they match the randomly selected numbers.

For example, if a player wins $5 and the bonus number is three, that player's total take is $15.

With Keno Bonus, players can increase their base prize up to 10 times, for a maximum prize of $400,000, according to the state Lottery Commission.

"It's important for the Lottery to be looking at new ways to add excitement value and entertainment to our portfolio of games," said Joe Sullivan, the commission's executive director, during a recent phone interview. "Keno Bonus is part of that overall program to generate more money for the towns and cities of Massachusetts."

Despite that "mission," Sullivan, along with many lawmakers, does not support the legalization of slot machines — widely considered by supporters as another source of state revenue.

Many opponents of slot machines argue that legalization could syphon money from the state lottery, an important source of local aid for communities.

Just last year, the Lottery Commission raised $742 million in Keno sales alone. Of that amount, 22 percent — about $35.9 million — was distributed as local aid to cities and towns.

"If there's going to be new gaming ventures in Massachusetts, we need to focus on ensuring that our state Lottery is protected," said Sullivan, echoing the position of state Treasurer Tim Cahill, who oversees the Lottery Commission. "The Lottery is an important revenue source for our cities and towns. Anything that might jeopardize the revenue needs to be looked at in a thoughtful and comprehensive manner."

Residents who spend more on slot machines would simply be spending that much less on the Lottery, said Rep. Dan Bosley, a North Adams Democrat, in a recent phone interview.

"How much more are you going to get out of the people who gamble in this state?" he said.

Bosley was not available to comment specifically on the Keno expansion yesterday.

The Lottery Commission, however, seems to be an exception to Bosley's statement. The last two years have been the Lottery's most successful yet, Sullivan said. In 2003, the commission collected about $925 million in gambling dollars. It topped that figure in 2004 with a final tally of $936 million.

The commission launched the original Keno game in 1993 and has since expanded the number of Keno agents from about 1,500 to the current 1,700.

Gov. Mitt Romney has promised to veto a bill to legalize slot machines if it gets passed by the Legislature.

"An expansion of gaming is not something the governor would support in light of the economic circumstances and social costs of gaming," said Romney spokesman Felix Browne yesterday, declining to comment on whether the public is tapped out in regards to gambling.

The Legislature's approval and the governor's signature are not required to establish new games under the Lottery Commission.