RICHMOND, FEB. 13 -- The Virginia House of Delegates gave preliminary approval today to legislation that would allow voters to decide in November whether pari-mutuel betting should be allowed in the state.

The chief sponsor of the horse racing measure, House Minority Leader Raymond R. Guest Jr. (R-Front Royal), predicted the bill will clear the remaining hurdles and be placed on the Nov. 8 ballot.

The referendum would take place just one year after Virginia voters approved a lottery, which has not yet sold its first ticket.

The proposal still must receive final passage in the House, pass the Senate, and be signed by Gov. Gerald L. Baliles.

A spokesman for the governor said Baliles has not taken a position on the question, but pointed out that as a member of the House, Baliles voted in favor of putting the issue to a referendum in 1978, when pari-mutuel betting was rejected by voters.

The legislation empowers a Virginia Racing Commission to decide details of how the gambling and tracks are operated. But it assures residents of any locality selected as the site of a track -- 5 percent of the residents must sign petitions requesting pari-mutuel betting -- that a second, local referendum will be held on whether they want a horse-racing track.

Although the legislation does not specify where a track or tracks would be built, spokesmen for the horse racing industry said a track undoubtedly would be built along the urban crescent between Washington and Norfolk.

Billy Camp, a Franklin County, Va., breeder of trotters and pacers who races his horses at the Rosecroft and Freestate raceways in Maryland, predicted a track would be built along I-64 between Richmond and Norfolk.

Camp said that because there already are several tracks in the Maryland suburbs of Washington, a Virginia track would likely be built between Richmond and Norfolk.

He envisions that it would feature racing every day of the year, divided between nine months of harness racing and three months of thoroughbred, or flat, racing.

C. Fred Kohler of Middleburg, president of Virginians for Racing, predicted that the state's first track would be built either between Washington and Richmond, or between Richmond and Norfolk.

He said a track could be operating within three years and would offer thoroughbred racing about 200 days, or nine months, a year.

Kohler represents the state's thoroughbred breeders, who contributed more than $20,000 to the campaigns of 33 members of the assembly during last fall's election campaigns.

Today's 50-to-45 vote must be ratified in a final vote, which is expected Monday but could come during a rare Sunday session.

Also today, the House rejected by a vote of 51 to 46, a bill by Del. David G. Brickley (D-Woodbridge) that would have required AIDS tests of all persons convicted of prostitution or intravenous drug use.

On a motion by Del. C. Richard Cranwell (D-Vinton), the bill was referred again to the House Courts of Justice Committee for inclusion in a comprehensive yearlong study of AIDS. It was one of nearly two dozen AIDS-related bills before the legislature.

An AIDS measure that won preliminary approval in the House today would require hospitals to alert funeral directors, by means of a toe tag, on the identity of persons who died of AIDS or other infectious diseases.

The House today also passed and sent to the Senate bills that would:Weaken the Conflicts of Interest Act by relieving most gubernatorial appointees from complying with the strict financial disclosure provisions added to the law last year.

Its sponsor, Del. Alson H. Smith Jr. (D-Winchester), said, "We're losing a lot of good people who have agreed to serve for free." About 15 of about 2,000 persons selected by Gov. Gerald L. Baliles refused to serve because of the law's detailed financial disclosure provisions. The bill passed 95 to 2. Exempt fox hunters on horseback from wearing blaze orange safety clothing or from taking a safety education course. Require animal wardens to get a warrant from a magistrate before picking up animals from a farm. Its sponsor, 70-year-old freshman Del. S. Page Higginbotham (R-Orange), said game wardens took "20 hogs, three cows and a goat" from his farm without due process.

The measure passed, 56 to 41, despite a warning by Del. Leslie L. Byrne (D-Fairfax) that its passage could contribute to cruelty to animals. Permit corrections officials to transfer unruly prisoners to mental institutions, or as its sponsor, Del. C. Hardaway Marks (D-Hopewell) put it, "If a dude . . . in the slammer . . . is off the wall . . . he can be committed to the looney bin." Require Arlington landlords to help defray the relocation costs of low-income tenants who must move because their buildings are being renovated.

The legislation authorizes payments ranging from up to $320 for tenants in efficiencies to $500 in three-bedroom units, to cover moving expenses and security deposits, and that tenants be given 120 days' notice.

In other preliminary action, the House today amended a bill relating to automobile insurance companies to remove a provision whose author said had been misconstrued as removing antidiscrimination protections.

Del. Frank D. Hargrove (R-Hanover), an insurance agent, said his proposal was meant to be a "pro-consumer" measure that would allow insurance companies to raise premiums as much as 200 percent, rather than cancel policies of high-risk drivers.

Hargrove said he did not intend for his amendment to delete protections against discrimination on the basis of race, age or gender.