ON PRIME-TIME television this year, it's going to be Saturday morning all week long. The new network TV season now upon us is the Season of Just Kidding, of Tongue in Cheek, of Cuteus Maximus. It may be the most speciously facetious new season in television history.

There'll be marauding monkeys, a telekinetic teen-ager, a supersonic zoom-o-car, sexy private eyes, wild animal hunts, blabby computers, a mythical kingdom, adorable pets and a suburban witch. Those who like their television dumb will be in hog heaven -- or Hogg Heaven, if they're "Dukes of Hazzard" fans.

When America was in the grip of the Great Depression, Hollywood rallied with daffy escapism, like Busby Berkeley's musicals. So should anyone really bemoan the fact that, in these economically pinched times, television is responding with oodles of fluff and folly? Yes, because it's going to be beamed into millions of homes every single night of the week--unlike the movies people went out to see in the '30s--and that much cotton candy, as any parent knows, can make you sick.

There is only one new drama series of substance in the fall schedules: NBC's "St. Elsewhere," which, like "Hill Street Blues," balances harrowing trauma with sardonic comedy. Otherwise, nearly all is spoof. Prime-time TV has always been fantasyland, of course, but the tone has changed. Even most of the remaining cop-and-crime shows are played half for laughs; heroes tend to be reluctant heroes or farce heroes, who take nothing seriously and are not to be taken seriously themselves.

This is the season of We Don't Really Mean It.

"Lou Grant" is gone now, and "M*A*S*H," that serious-minded comedy, will end its long run at mid-season. We are left with hours of wan tomfoolery as the networks scramble for what remains of a dwindling audience. They have revved up the talking car and unleashed the screeching apes, and this is how they expect to hold onto a public increasingly lured by pay television, discs and tapes, and video games that go bzrt in the night.

Ten years ago, the prime-time schedule included six hours of musical-variety programming (including the Carol Burnett and Flip Wilson shows) and eight hours of weekly drama. The dramas weren't Shakespeare, or even Paddy Chayefsky -- they were genre shows like "Marcus Welby, M.D.," "Gunsmoke" and "Owen Marshall, Attorney at Law" -- but at least they were on the level, and semi-serious in intent.

This year, it's mainly winks, twinkles and tickles. ABC's "Matt Houston" is a private eye, but also a multimillionaire who does his sleuthing merely as a lark and operates out of an L.A. penthouse -- they couldn't have fetched it any farther. NBC's "Devlin Connection" is about a private eye who is really the head of an arts center. You know, the kind of guy you run into every day.

Many of the new shows feature voice-over narrations (a la "Magnum, P.I.") to guide viewers along and help maintain spoofy tones. The narrator of ABC's "The Quest" even says, "So now, our story begins." Radio-serial narration for NBC's "Knight Rider" introduces its mock-hero with, "In the dead of night, Michael was cradled up into the arms of destiny . . ." The networks want to appeal to the child in all of us -- preferably, if they can get away with it, the idiot child in all of us.

As usual, last year's movie hits turn up with minor alterations as this year's new TV shows. And so, imitations of "Raiders of the Lost Ark" materialize. ABC has its insipid "Tales of the Gold Monkey" and CBS its dum-dum "Bring 'Em Back Alive." Both shows feature flip, rumpled leading men and spunky, assertive heroines -- the latter a token nod to '80s feminism that clanks discordantly in the adventure-movie settings. But nobody appears to be taking any of it seriously. It isn't satire, it isn't even at the level of japery, it's all part of one large prank.

These programs want to remind viewers of movies or serials they once liked -- they are bloodless clones, pod programming. The pilots for both "Gold Monkey" and NBC's "Remington Steele" make pointed references to the movie "Casablanca," which itself is being remade as a TV series for later in the season(!). But putting up bars that look like Rick's Place and having a piano tinkle out "As Time Goes By" in the background are hardly enough to duplicate the magic and incandescence of yesteryear's great escapes.

Not everything looks hopeless. NBC has a sparklingly caustic new comedy series, "Cheers," to brighten up the landscape, the CBS sitcom "Square Pegs" is promisingly offbeat, "St. Elsewhere" comes from MTM, the home of "Hill Street," and advance word on ABC's "Star of the Family" indicates it may be slightly less inane than the average sitcom.

And the networks are planning specials and mini-series packages that include ABC's ambitious treatment of Herman Wouk's "The Winds of War," on which gargantuan bucks are being spent; an eight-hour adaptation of Bruce Catton's Civil War epic "The Blue and the Gray" on CBS; and NBC's four-hour version of Norman Mailer's "The Executioner's Song," about executed killer Gary Gilmore (plus a repeat of "Shogun").

In competitive terms, CBS, last year's ratings winner, comes into the new season looking unexpectedly shaky; most of its new shows are feeble, an NFL players' strike could seriously damage the network's winning Sunday-night lineup, and public rejection of the new "Dukes of Hazzard" stars may throw a monkey into the Friday night CBS money grinder. ABC is again relying on artificially sweetened popcorn and crackerjack, hoping to snare dull-witted but strong-willed children. And NBC, having apparently recovered from several years of dementia peacox, is introducing the most ambitious and respectable of the new programs and aiming for a young urban viewership to help turn around its sagging fortunes.

As further inducement to look elsewhere for entertainment, all three networks are adding additional 30-second commercials to prime time. Most of this new ad time comes from time previously allocated to promos, but the clutter isn't likely to leave any viewers delighted. TV Guide editorial director Merrill Panitt asked in a recent article if the networks were trying to commit suicide. On the basis of the new season, the answer is yes, but they're not going to shoot themselves. They're going to beat themselves cuckoo with a pig bladder.

The silly season, the truly silly season, is upon us. New ABC Shows

ABC was the least cooperative network when it came to screening new programs in advance; hence evaluation of some of its programs must be based on industry scuttlebutt.

* "Ripley's Believe It or Not" is the latest sacrifice to be sent in against the CBS powerhouse "60 Minutes." Cohosts Jack Palance and Catherine Shirriff will totter through a "That's Incredible!" smorgasbord of allegedly fascinating oddities, including, on the first show, a visit to a Denmark bog where the remains of 2,000-year-old bodies have been found. This series can prepare to join them (Sundays, premiering Sept. 26).

* "Matt Houston." ABC thinks it has found a new lanky hunk for our times in beefy-goofy Lee Horsley, who has perfected a delivery that's strictly James Garner Wry and who, in this twangy dud of a detective show, plays a millionaire Texas oilman who has a hankerin' to do sleuthin' on the side. He also has an L.A. penthouse, a chatty computer named Baby and a perpetual entourage of pretty women. Even his mechanic is a gorgeous blond. Top aide and series narrator "C.J." (Pamela Hensley) notes at one point, "Some people don't like Houston too much." Those would be people who are still in their right minds (Sundays, premiering Sept. 26).

* "Tales of the Gold Monkey," originally titled "The Brass Monkey," was of course produced by would-be Cloners of "The Lost Ark." Stephen Collins does the Harrison Ford bit as a danger-courting pilot who hopscotches through the South Pacific circa 1938, his one-eyed dawg Jack at his side. There are Nazis, and Japanese secret agents, and a solid-gold idol guarded by apes prone to snits, and a tediously feisty love interest for Steve. All in all, a smug, laborious lump of a romp (Wednesdays, premiering Sept. 22).

"Star of the Family" sitcomically examines the tensions and traumas that result when the fickle finger of fame lifts a 16-year-old girl (Kathy Maisnik) into rock superstardom much against the wishes of her firehouse-captain father (Brian Dennehy). Executive producer Larry Grezner worked on a great comedy called "Good Time Harry" (by "Arthur" author Steve Gordon) a few years ago -- a good sign (Thursdays, premiering Sept. 30).

* "It Takes Two," once called "For Better or for Worse," stars Richard Crenna and Patty Duke Astin as married parents trying to adjust to the wife's late blooming. She's begun a career as a prosecuting attorney; he is chief of surgery at a Chicago hospital. Created by Susan Harris, who splashed "Soap" in America's eyes (Thursdays, premiere date to be announced).

* "The New Odd Couple." Felix and Oscar have not been renamed Amos and Andy, but the characters are now played by black actors Ron Glass and Demond ("Sanford and Son") Wilson in a variation on the original Neil Simon play about mismatched roommates. Some black actors have criticized producer Garry Marshall for allegedly taking old "Odd Couple" scripts and just blacking them up (Fridays, premiere date to be announced).

* "The Quest" was launched by talented Stephen J. Cannell ("Rockford Files," "Greatest American Hero"), but the bright Cannellian humor can't quite redeem a contrived fantasy in which four Americans learn that one of them could become heir to the throne of Glendora, a tiny kingdom near France. Each week the four comrades embark on another leg of the kind of "quest" their ancestors completed in the 13th century. Passably amusing but awfully "So what?" (Fridays, premiere date to be announced.) New CBS Shows

* "Gloria," once Gloria Bunker -- daddy's "little girl" -- later Gloria Stivic, is now separated from her husband and, in this "All in the Family" spinoff, living with a crotchety country veterinarian (Burgess Meredith, who does not look well) and Gloria's 8-year-old son Joey in upstate New York. Sally Struthers is still appealing as Gloria, and both Rob Reiner as Mike and Carroll O'Connor as Archie will probably make guest appearances during the year, but the situation and surroundings of this new comedy ring sadly false, as if not even those who made it can manage to believe it (Sundays, premiering Sept. 26).

* "Square Pegs" has novelty, spunk and intelligence going for it -- or against it, if you're cynical about what succeeds on TV. Patty Greene (Sarah Jessica Parker) and Lauren Hutchinson (Amy Linker) are freshmen at Weemawee High School and desperate to succeed. Their friends include Johnny Slash (Merritt Butrick), a whacked-out New Waver, and their foes include grody Jennifer DeNuccio (Tracy Nelson), a boy-crazy Valley girl who suffered the biggest crisis of her life the day she left her makeup in the car at the beach and it melted. Produced by Anne Beatts, a key writer on the original "Saturday Night Live" (Mondays, premiering Sept. 27).

* "Newhart" -- Bob, that is -- returns to TV 10 years after his previous show was launched. This time he's not a shrink but a writer of handyman books ("Know Your Harley") who, with wife Mary (Joanna Loudon) has decided to restore and operate a Vermont inn built in 1774. This inn is ollld. When a guest signs in, Newhart says, "Just give me your John Hancock." Guest: "Where?" Newhart: "Right there, under John Hancock." The show is quietly funny and likable, but saucy Suzanne Pleshette, once Newhart's perfect foil, is sorely missed, and Newhart's fumble-bumble routine has not aged well (Mondays, premiere date to be announced).

* "Bring 'Em Back Alive," another result of raiding "Raiders of the Lost Ark" for series ideas, stars blank Bruce Boxleitner as big-game hunter Frank Buck, who traipses around Malaya and Singapore in 1939, bagging cats and dodging Nazis. Like ABC's "Gold Monkey," the show is flippant and frivolous. Secret papers, spies, and a wickery bar are meant to recall movies of the '40s and serials of the '30s, but the seltzer lacks fizz. What you get is awfully low high adventure and middling mid-level camp (Tuesdays; "sneak-previewed" Sept. 24).

* "Seven Brides for Seven Brothers" doesn't so much attempt to tickle ribs as elbow them to bits. It's more a rube-tickling show, actually, based, just barely, on the MGM musical about how a pretty young girl is hoodwinked into marriage to an hombre with six brothers to cook for and clean up after. There's some singin' and dancin' each week, as choreographed by Onna White, but it's all drownin' in antiseptic. The first episode involves a county fair and a stolen bull -- actually, stolen bull just about sums the whole thing up (Wednesdays, "sneak-previewed" tonight at 8 on Channel 9).

* "Filthy Rich," a shrill and nasty sitcom about backbiting heirs to a vast estate, had a successful run this summer and was rushed in by CBS to replace the scheduled "Mama Malone" (still in production and a possible mid-season starter). Vulgar, loud, rude and coarse -- and those are its good points (Wednesdays, premiering Oct. 6).

* "Tucker's Witch," originally "The Good Witch of Laurel Canyon," chronicles the antics of husband-wife private eyes; the wife, as might be guessed, has supernatural powers. Because of excessive remodeling work being done on the show, it was not available for screening. Tim Matheson and Catherine ("Marilyn") Hicks star (Wednesdays, premiering Oct. 6). New NBC Shows

* "Voyagers!" was obviously inspired by the hit movie "Time Bandits"; still, these tales of an 11-year-old orphan who bounces around in time with a klutzy adventurer ("Phineas Bogg," as in "Phineas Fogg," get it?) are fairly cute, well produced, and careful to mention correct dates and places, to the certain delight of history teachers everywhere. "Time is our oyster," the voyager says, but "60 Minutes" is their competition (Sundays, premiering Oct. 3).

* "Gavilan," an unseen commodity, stars Robert "Vegas" Urich as a former CIA agent who each week, NBC says, "will experience a new adventure in his quest for justice and fairness," teamed with a female associate who's the "beer-drinking, Tugboat-Annie type." A pilot film made last spring was a disaster, and the show has undergone extensive repairs (Tuesdays, premiering Oct. 19).

* "St. Elsewhere" is the nickname of St. Eligius, a dilapidated old Boston hospital, which one cantankerous sawbones (William Daniels) derides as "a dumping ground, a place you wouldn't want to send your mother-in-law." Produced by MTM, and therefore widely considered to be a medical "Hill Street" (they might have called it "Beacon Hill Blues"), the program has undergone severe script and development problems. And then the studio in which it was filming was condemned by the fire department! So it's an unseen but still promising show, and the only new hour of serious drama to be introduced by any network for the fall (Tuesdays, premiering Oct. 19).

* "Family Ties" flip-flops the generation gap for fairly amusing results. The parents are the hipsters -- former peaceniks who married during the shaggy '60s -- and their kids the squares, especially a teen-age son who likes three-piece suits and prefers the Wall Street Journal to Pac-Man. Moderately funny, but essentially a one-joke show (Wednesdays, premiering Sept. 22).

* "Cheers" are in order for "Cheers," which looks to be the best new comedy series of the season and a valuable, endearing addition to contemporary TV mythology. Cheers is the name of a Boston bar (it's a big year for New England on TV) that exists because, the theme song says, "Sometimes you wanna go where everybody knows your name." Also, when the phone rings there, and the waitress asks loudly, "Who isn't here?," about a dozen male voices respond with, "Me!"

The show opens with a rousing and touching introductory episode. Shelley Long, so fine as the friendly hooker in the movie "Night Shift," plays a young woman whose boyfriend has promised her a trip to the Caribbean, but the rat reneges and Long is left at the bar, where she is offered a job by the affable, ex-alcoholic bartender played by Ted Danson. Other regulars include "Coach" (Nick Colasanto), a maniacal sports fan who's been reading the same novel for eight years, waitress Carla Tortelli (Rhea Perlman), determined to wreak vengeance on all living males because her husband deserted her and their four children, and Norm (George Wendt), whose credo of life is simply -- and frequently -- stated: "One more quick one." A great new comedy with a big fat heart (Thursdays, premiering Sept. 30).

* "The Powers of Matthew Star," humorless hokum about a telekinetic teen who drops in on Earth from the planet Quadris, stars Peter Barton as the kid (he looks less the "superhunk" ballyhooed by NBC than he does a skinny Phyllis Kirk) and Louis Gossett, so sensational in "An Officer and a Gentleman," as his guardian. Not enough special effects to keep kids hooked (Fridays, premiered Sept. 17).

* "Knight Rider" features a souped-up Trans Am outfitted with a prissy-voiced computer, a high-tech mansion, a billionaire crimefighter who kicks off in the first episode, and a pretty-boy hero who stalks around numbly saying things like "I can't believe this." And who would bother trying to? Dull derring-do (Fridays, "sneak-previews" Sept. 26).

* "Remington Steele" brings tony sex appeal to the private-eye format. The twist is slick: A woman runs a detective agency, but named it after an imaginary man, Steele, because she feared people wouldn't take a lady seriously. Then a real Steele shows up, feeling not so imaginary after all, and she reluctantly takes him in, even though he's a bed-hopping playboy. Costars Stephanie Zimbalist and Pierce Brosnan definitely set off sparks (Fridays, premiering Oct. 1).

* "Silver Spoons" stars icky Ricky Schroder as a 12-year-old whiz kid who must try to shape up his father, an imbecilic millionaire who abandoned the tot years earlier. Dim and flimsy whimsy (Saturdays, premiering Sept. 25).

* "The Devlin Connection" finds Rock Hudson returning to series television (one year belatedly, after a heart attack) to play the head of an arts center who also solves murder mysteries with the help of his long-lost son Nick (model-not-quite-turned-actor Jack Scalia). NBC offers the plot of the first show: "Devlin is drawn back into detective work when he must find an antidote to an Asian virus injected into his son . . . by expert assassins trying to recapture a scientific genius for whom the young man is serving as bodyguard." It is to snore (Saturdays, premiering Oct. 2). Public Television

Though never before so financially strapped -- despite a history of perpetual strapping -- the Public Broadcasting Service is still coming up with five new series for the fall and, in the winter, a return of the much-needed and often excellent "American Playhouse" series.

The new public TV series:

* "Six Great Ideas with Mortimer Adler and Bill Moyers," which certainly gets the loftiness award, sight unseen, finds Moyers and Adler discussing and conducting seminars on the topics of truth, goodness, beauty, justice, equality and liberty. Moyers, the bionic renaissance man, is also executive producer (premieres Monday, Oct. 25).

* "Screenwriters/Words Into Image," another six-parter, hunkers down with six Hollywood screenwriters of past or present for illustrated discussions of the movie writer's craft. Those who participated: Neil Simon, Paul Mazursky, William Goldman, Robert Towne, Carl Foreman and the late Eleanor Perry (premieres Sunday, Oct. 10).

* "Wild America" is a 10-part, on-the-road look at American wildlife (premieres Thursday, Oct. 14).

* "Nature," a 13-part series, examines exotic or prosaic animals and their sometimes inscrutable behavior, in such diverse habitats as Costa Rican rain forests and the Serengenti Plain (premieres Sunday, Oct. 10).

* "The Magic of Dance" is Dame Margot Fonteyn's six-part conducted tour of dance history and her own illustrious 40-year career, with classic dances recreated by such artists as Nureyev, Baryshnikov, Makarova and Ivan Nagy, plus lighter side interviews with pop artists like Fred Astaire and Sammy Davis Jr. (premieres Monday, Oct. 25).

"American Playhouse" begins its new season on Tuesday, Jan. 18, with a live telecast of a new production of Thornton Wilder's "The Skin of Our Teeth," with a cast still to be selected. The play will originate at San Diego's Old Globe Theater. Other "Playhouse" offerings this season include "Hands Across the Sea," a three-part mini-series about four decades in the lives of a black G.I. and the Englishwoman he courts and marries; Lanford Wilson's off-Broadway hit "The Fifth of July," starring Richard Thomas as a paraplegic Vietnam vet and Swoosie Kurtz, who won a Tony for playing the part of Gwen on the New York stage; "Family Business," a TV adaptation of Dick Goldberg's play about squabbling sons and a dying father that was filmed in August in Washington and stars Milton Berle; and plays by, or adaptations of works by, Jean Shepherd, Truman Capote, Philip Roth, John Updike, and Isaac Bashevis Singer.

The "Mystery" series will offer a 90-minute straight dramatic version of "Sweeney Todd," the Broadway musical version of which is now appearing on cable TV's Entertainment Channel. "Great Performances" will include Wagner's Ring cycle and the Met's production of Humperdinck's "Hansel and Gretel." Among the alleged masterpieces on "Masterpiece Theater" set for this season are "To Serve Them All My Days," an 11-parter about a British boys' school; and "Winston Churchill, The Wilderness Years," about the times when Winnie was out of power. Among "The Shakespeare Plays" to be mounted this season: "Richard III" and "King Lear."

Although PBS will reprise the mordant and suspenseful 1980 hit "Tinker, Tailor, Soldier, Spy," the John Le Carre sequel, "Smiley's People," will be seen instead on commercial TV via syndication (in Washington, WDCA-TV, Channel 20). Also set for syndication: Mobil's nine-hour, four-part taped version of last year's Broadway smash "Nicholas Nickleby," from the Charles Dickens novel (Jan. 10 to 13 on WTTG-TV, Channel 5 here). Pay TV

Pay TV services will be more deeply involved than ever this season in original production, to supplement their first-run movie fare.

Home Box Office, the nation's largest such service, premieres its $2 million production of "Camelot," starring Richard Harris, on Sept. 26. Other highlights of the HBO season ahead include Bette Davis and James Stewart costarring for the first time on TV in "Right of Way," a Golden-Pondish drama to be directed by the brilliant George Schaefer; "Fraggle Rock," a half-hour weekly series, premiering in January, that introduces a new breed of Muppets called Fraggles; Frank Langella recreating his Broadway (and movie) role as "Dracula" in early '83; and the six-part "Chandlertown," based on works of Raymond Chandler, also early next year.

Showtime, HBO's chief rival, claims it will get the first made-for-pay-TV movie onto the air, or rather into the air by satellite, in December. It's called "Falcon's Gold" and, told "it sounds like another dumb 'Raiders of the Lost Ark' thing," a spokesman sheepishly conceded, "Well, basically, true." But Showtime has other stellar attractions on the bill, including Frank Sinatra's "Concert for the Americas" taped Aug. 20 in the Dominican Republic (Sinatra is suddenly very hot for cable TV); the final concert of the now-disbanded Doobie Brothers (to be shown in January); a salute to one of the earliest geniuses in television, Ernie Kovacs, that will include material never previously seen on the air, contributed by Kovacs' widow Edie Adams (November); and "Shelly Duvall's Faerie Tale Theater," a series of fables coproduced by, and occasionally starring, the ingenuous actress.