In what one lawmaker called a "new way of playing taps," the Virginia House of Delegates today sent back to committee a measure that would raise the legal age for buying beer from 15 to 19.

The delegates heard extensive arguments for and against the bill -- sponsored by Del. Warren E. Barry (R-Fairfax) -- before voting 54 to 36 to recommit the measure to the General Laws Committee from which it came.

The suggestion to send the bill back to committee came from its chairman, Del. Thomas W. Moss Jr. (D-Norfolk), who strenuously opposed the bill when that panel narrowly approved it last week.

Moss said he wanted the committee to study two amendments offered during floor debate today, but delegates who subsequently approved his request laughed aloud in the chamber when he made it.

"It's the first time I've heard taps played that way before," said Del. Frank M. Slayton (D-Halifax), who assumed, as did his colleagues, that the bill never will make it out of the Moss committee a second time.

Moss denied this today, but said the measure will be in trouble if it remains in its present form.

The amendments now before the committee would raise the age to 18 1/2 and only allow those aged 19 or over to buy beer that could be consumed away from the place of purchase.

Barry, who said he supports the latter amendment, said his bill is aimed at getting alcohol out of the schools and cutting down on teen-age drunk driving and alcoholism. Moss has agrued that Barry's bill will not solve the problem.

In other House matters, the leadership reported today that about 2,700 bills are expected for the legislature's consideration during this "short" session, more than were acted upon in a 60-day period last year.

In the Senate's first major action of the young assembly session, it barely approved a House-passed bill that would require governing boards of the state's colleges and universities to hold open meetings. The vote on the controversial measure was 20 to 19.

The college boards are the only public education bodies that are now exempt from Freedom of Information Act provisions that require open meetings.

Influential senators, including Hunter B. Andrews (D-Hampton), chairman of the Senate Education Committee, and J. Harry Michael Jr. (D-Charlottesville), whose district includes the University of Virginia, argued strongly against the bill.

They said the open meeting requirement will inhibit discussion of "sensitive matters" and is unnecessary because board members are available for questioning after meetings.

Sen. Joseph V. Gartlan (D-Fairfax) argued that board minutes and post-meeting questioning tell "something less than the whole story" of deliberations by these state boards. "Why not tell the whole story?" he asked.

Sen. Wiley F. Mitchell Jr. (R-Alexandria) said sensitive discussions involving college personnel and possible litigation already are excluded from coverage by the Freedom of Information Act.

The bill now must go to a House-Senate conference.