Hats off to John Jacob for pinpointing a significant new social trend in the Great Hereabouts. John says the big difference between Washington 1958 and Washington 1988 is which suburbs we make fun of.

Thirty years ago, John says, the automatic laugh-getters were Hyattsville and Beltsville. Pick a put-down, any put-down, and you could make it a laugher with a reference to "either of the two Prince George's 'villes' -- The Big H or The Big B,' " John says.

Example: Q -- What do you call a guy who's wearing a brown suit and white socks? A -- A guy from Hyattsville who's on his way to church to get married.

Second example: Q -- What's the difference between the right side of the tracks and the wrong side of the tracks? A -- In Beltsville, there's no difference.

But now, sprawl has sprawled, and jokes have found new butts. The prime targets these days, says John, are Bowie, Gaithersburg and Dumfries.

Bowie takes it on the chin, John thinks, because its first syllable is so deliciously pronounceable. "You want to say boo-o-o-o-o-o to something, it's not much of a journey to say Bo-o-o-o-o-wie instead," John points out.

Gaithersburg is in the '88 top three for two reasons: 1) It's so far from downtown D.C. that it "might as well be in West Virginia" and 2) Its name implies that "a guy named Gaither still milks cows out there. That's a natural for hick jokes," John says.

Dumfries makes the list, says John, for two reasons, too: 1) The name just plain sounds funny, the way Kalamazoo or Walla Walla sound funny and 2) The first syllable is so close to "dump" that any and all comparisons are hard to resist.

A grateful metropolitan area salutes you, John. No longer will D.C. wiseacres have to wait for New Year's Eve lists to learn what's in and what's out in the world of put-down humor. You've smoothed the way.

However, you've also induced me to issue a warning, from the foxhole I inhabit:

If you're going to beat up on Bowie, Gaithersburg and Dumfries, expect return flak.

I haven't trained my typing fingers on the first two towns on your list. But a couple of years ago, I spun a fantasy in which Dumfries replaced Georgetown as the most stylish part of the Washington area. You know, half-a-million dollar houses just down the road from Dale City, French restaurants where cows and 7-Elevens once stood, that kind of thing.

The mail divided neatly into halves. The first half was from proud Dumfrians who invited me down to have a look for myself. But I never accepted the offer because of the second half.

These were the gun-rack-in-the-back- of-the-pickup people who didn't appreciate the slight. One guy I remember very well indeed. He wrote that I should come for a visit and change the name of the column to Bob Levey's Dumfries. "Since you'll never get out in one piece, it would only be appropriate," he said, comfortingly.

Anyway, I couldn't let John go without asking him two questions.

Where does he live? "I was ready for you on that one. Bo-o-o-o-o-o-o-wie. So I'm entitled to tell Bowie jokes."

Second question: Which suburbs will be punch lines 30 years from now? Will they still be Bowie, Gaithersburg and Dumfries?

"Not a chance," he said. "They'll be Manassas, Frederick and Glen Burnie."

Time -- and targets -- march on.

As Feb. 29 approached, I began to wonder if Lil Palm of Southeast would call. She didn't disappoint.

Readers with elephantine memories will recall meeting Lil in this column on Feb. 29, 1984. She advertised herself that day as the only Mom in creation with sons born on successive Leap Year Days. Those offspring were (and are) Mike Palm Jr. (born 2/29/48) and Herb Palm (born 2/29/52). Since no Mom ever sprang forth to dispute Lil's claim, the title remains hers.

Well done, Mom. And Happy Birthday (after a four-year wait) to Mom's two sons. As Lil says, "it's quite something for a woman my age to have one son who's 10 today and another who's 9."

Bob Orben says Yuppieism has become such a religion that there's now a Yuppie church. It believes that Adam and Eve were banished from the Garden of Eden because they ate of the forbidden quiche.

Stu Krasner of Potomac says robins are no longer a sure sign of the arrival of spring out his way. Neither are crocuses.

The best hallmark: The first ChemLawn truck.