With only hours left before the Cambridge polls opened, candidates for city-and county-wide posts hit the streets, squares and subway stations yesterday for a last-minute pitch to voters.

Braving the crisp fall air of Central Square, Democratic candidate Larry W. Beeferman began his rounds early yesterday handing out flyers, talking to potential supporters and complaining about catching pneumonia.

Beeferman is challenging incumbent State Rep. Alvin E. Thompson in Cambridge's 28th Middlesex District. Thompson, who has held the post since scoring an upset victory two years ago, had his own corps of supporters in the square, waving signs and soliciting support for the incumbent.

While the two candidates agree on a number of issues, generally favoring a liberal social agenda, each has tried to portray himself as significantly different from the other.

Beeferman has attempted to tie the incumbent to the legislature's inabilty to solve the state fiscal crisis, while Thompson has emphasized his experience on the job and his ties to the community.

"When it came to the budget and taxes he rolled over and played dead," Beeferman said yesterday, taking a few jabs at his opponent. "He didn't ask and he didn't think."

Thompson however voiced confidence that he will be returned to office. Speaking from his home before a final blitz on the Cambridge subway stations, the incumbent described himself as an active and knowledgable representative.

"I know my way around state government. Its a busy place," said Thompson. "He's a talker and I'm a doer."

D.A. Politicking

Candidates facing off in the Democratic primary for the job of Middlesex District Attorney also did some last minute politicking. Because there are no Republican candidates, the winner of today's primary will be the next D.A.

Three candidates have thrown in their hats into the ring to succeed Middlesex D.A. L. Scott Harshbarger '64, who is running for state attorney general. The top contenders appear to be State Rep. Joseph K. Mackey and Harshbarger's former chief deputy, Thomas F. Reilly.

Also in the race is George Spartichino, a Cambridge lawyer and former state represenatative who has recieved less media attention.

Mackey and Reilly--who have waged a mini-war of negative advertising--each claim they bring the better background to the job.

Mackey spokesperson Thomas M. Keane, Jr. said that Reilly views the job of D.A. as merely an "elected professional position," and claims that his candidate's legislative background is a necessary asset for the job. Mackey has emphasised drug enforcement and prosecution of environmental crimes as priorities.

Reilly, who is running on his record of successful prosecution of several high-profile cases and his experience as an attorney, claims Mackey does not have the right background for the job.

"We think it is a manager's position and we think Joe Mackey does not have managerial experience," said Jeff Shapiro, Reilly's campaign manager.

`Building Up Steam'

While the other campaigns only expect Spartichino to take 10 to 20 percent of the vote--possibly taking votes away from Mackey--his campaign says the race is not yet over.

"We've been running a grassroots campaign since January and we've been building up steam since then," said Gene S. Trioli, the Spartichino campaign manager.

"Because the other two candidates were attacking each other the focus has been on them," said Trioli.