Maryland Gov. Harry Hughes vetoed today, for the second time, a bill to allow the return of slot machines to eight Eastern Shore counties.

The bill, virtually identical to a measure Hughes vetoed last year, would have allowed fraternal, religious or veterans groups in eight counties to own and operate up to five machines each, as long as half the proceeds were given to charity. Favored by Shore legislators and some nonprofit groups as a fund-raising tool, the measure has been strongly opposed by Hughes and some lawmakers who maintained it would lead to the statewide spread of the gambling devices that have been outlawed here since 1963.

"He vetoed it for the same reasons as last year," including the fear of setting a precedent of allowing the machines, said Benjamin Bialek, Hughes' chief legislative aide. He added that "the lack of enforcement provisions creates a serious loophole in the possession of slot machines."

The veto came after a public ceremony in which Hughes signed 173 bills, including measures to require criminal background checks of certain child care workers, to allow crime victims to address a sentencing judge or jury before sentences are rendered, to give $14 million in additional aid to local schools, and to make it easier for people who provide day care in their homes to obtain needed liability insurance.

At times the bill signing ceremony, one of several Hughes will hold before the May 27 deadline for signing or vetoing measures approved in the 1986 General Assembly session, took on a carnival air as dozens of lawmakers and activists filed in to have their pictures taken with the governor and legislative leaders.

Del. Lucille Maurer (D-Montgomery) passed out drawings of camp shorts touting her bill to require licensing of summer camps. Sen. Howard Denis (R-Montgomery) whispered, tongue in cheek "the sour cream bill is mine" as he filed past. That bill allows stores to sell various-sized containers of yogurt, sour cream and cottage cheese, but the credit belonged to Sen. Norman Stone (D-Baltimore County).