The best bets in racing are not esoteric horses ferreted out by subtle handicapping methods. They are horses of obvious merit that the public somehow misjudges.

Last month at Saratoga, I suggested that readers bet the rent on a horse named Party King, who won in a breeze and returned $9.60 for each $2 of rent money. Much as I would like to take credit for special genius in picking the winner, he was ridiculously obvious, having won his last start in the same company by seven lengths. But the bettors at Saratoga underrated him because he was an invader from the boondocks of Delaware.

A similar situation exists in today's eighth race at Belmont Park, the $75,000 Maskette Stakes, which will probably determine the country's champion filly of the year. Pearl Necklace is a three-star mortal lock to win it. Yet the public is likely to underrate her, and overrate her rivals Davona Dale and It's In The Air, creating a profitable betting situation.

Pearl Necklace's virtues are obvious: she is the top money-winning Maryland-bred filly of all time. Last year, she was the second-best 4-year-old of her sex in America, and this year she has fully bloomed.

She won four straight races on the dirt by a total of 18 lengths this spring, then was rested for two months and returned to competition on the grass At Saratoga and Belmont, she faced top-class filly turf specialists, spotted them weight and won under restraint.

Ordinarily, a horse with a six-race winning streak would be an overwhelming favorite, but Pearl Necklace's rivals come into the Maskette with formidable reputations.

Davona Dale looked like the best filly in the country earlier this season; in fact, she looked like one of the best of all time. She won stakes in Florida, Louisiana, Arkansas, Kentucky and Maryland before sweeping New York's triple crown series for fillies. But this tough campaign evidently took its toll on her.

Davona Dale was upset by It's In The Air in the Alabama Stakes at Saratoga. Trainer John Veitch was not convinced by this defeat that his filly was tailing off, and entered her the next week against males in the Travelers Stakes.She was trounced, running the worst race of her life.

Davona Dale evidently needs a rest. There is no evidence to suggest that she is about to rebound from a 29-length loss in the Travers and regain her midseason form. But the betting public loves her and will surely support her heavily today.

It's In The Air was undeservedly voted the cochampion 2-year-old filly last year, but was unable to win a stakes race this season until the Alabama at Saratoga. Not only was she facing a subpar Davona Dale, but everything favored her that day. The racetrack was giving a tremendous advantage to front-runners on the rail -- eight of nine races on the card were won by speed horses -- and It's In The Air was the only speed horse in the field. She was able to get to the rail and set her own comfortable pace until Davona Dale challenged her.

It's In The Air followed that victory with a five-length romp in the Dela- ware Oaks against nondescript 3-year olds. Again, all the conditions favored her. She was able to set her own leisurely pace, running the first half mile in 48 2/5 seconds. (On the same day, $5,000 claimers were covering the same distances in 47 3/5 seconds).

Against Pearl Necklace's speed, It's In The Air will have no such cakewalk today. Both she and Davona Dale look so vulnerable that they could finish out of the money in the six-horse field.

The only question about Pearl Necklace is her price. She deserves to be an odds-on favorite, but because of the reputation of her challengers, she probably won't be. She could go to the post at 7 to 5 or thereabouts. At such a price, even a prudent man would feel obliged to bet the rent.