Part of the fun of "The Betty White Show," a new CBS comedy series premiering tonight, lies in the opportunity it gives its cast and writers to take a few healthy nibbles at the jolly green hand that feeds them - network TV.

On the opening show, at 9 p.m. on Channel 9, White, as TV-actress Joyce Whiteman, awaits the verdict on a pilot she's made for a series called "Undercover Woman," directed by her ex-husband John Elliot (John Hillerman).

Did CBS like the show? Well, he tells her, network brass found it "lurid, tasteless, cheap, ludicrous, far-fetched and only suitable for someone with the mentality of an 8-year-old."

Right - but did they like it? "They loved it," he says. "They wish they had 20 more like it."

Twenty more shows like "Betty White" might be a few too many, but this one will obviously be nice to have around. It has the brightness and bite we have come to expect of MTM productions (the program is taped in Mary Tyler Moore's old studio) and presents a gallery of cleverly-realized characters bubbling over with funny fallibilities.

ABC has made so much money with punk comedy, kid comedy and rube comedy - and, with "Soap," will be trying for a hit with smut comedy - that a show as well-crafted and basically civilized as White's seems almost naively subtle and warm, like a throwback to a less gimmicky age. It is very possible that White's half-hour will prove the closest thing to wittiness regularly on the air this season.

The premiere, written by David Lloyd and directed by Bill Persky, may be too dependent on insults for its yocks, with White and Hillerman sparring and spatting each time they meet, but White, under-utilized as an actress until she played Sue Ann on "MTM," tosses off nasty cracks with a blitheness that makes amusing moments of moral victory over phonies stuffed shirts and dullards.

One of her principal targets is a sexy young actress played on the first show by Carla Borelli but later recast, who likes to flaunt her hyperactive love life. "Oh yes," she gushes, "the first time is always so special," and White responds, "What a memory you have?" Predictable, perhaps, but still pretty delicious, thanks to White's delivery.

Hillerman injects a fresh note for TV, underplaying his implacability in a manner that recalls black-tie comedies of the stage and matinee idols of the '30s. But the writers are going to have to let him soften more often to White's importunings if the show is to avoid a potentially frustrating rut.

Georgia Engel, ex-Georgette of "MTM," plays a similar sweet dumbbell here; Batney Phillips is funny as a jittery actor who turns Rock of Gilbralter when cameras roll; and Charles Cyphers is believably burly enough to get easy laughs in drag as White's stand-in for action scenes. Alex Henteloff, as a CBS censor, bears the brunt of the anti-television jibes and personifies an entire race of avaricous simpletons - those mean old network executives.

They couldn't all be that bad, or "The Betty White Show" wouldn't be on the air. May it remain as a civil-tongued stranger in a universe increasingly populated with callous screamers. 'Young Dan'l Boone'

All the characters on "Young Dan'l Boone" are strictly respectful of that apostrophe; nobody calls Dan'l "Daniel." This is only fair, since the program is nothing but an apostrophe itself - a punctuation mark masquerading as a word.

"He could see a country, a-waitin' round the bend," sings the title-tune chorus as the new CBS adventure series premieres tonight, at 8 on Channel 9. And, gosh a-mighty, that's just a little taste of the heap o' cliches to come.

Young Dan'l, who, as played by Rick Moses, looks like a surfer in Bloomingdale deerskin, wants to go off to "Cane-tucky" through the Cumberland Gap and get himself a piece o' the continent. But his sweetie, Rebecca, don't want him to go. This leads to some pretty sophisticated colloquy.

Dan'l: 'Now ever since I kin recall I wanted to find me a place where I kin stand on the stump of a hill and look for a hundred miles and not see nothin' God didn't put there."

Reb'cca: "Seems to me I've heard this nearly a thousand times before. Dan'l."

And who hasn't?

"Daniel Boone," which starred Fess Parker and ran on NBC from 1964 to 1970, covered its territory much better making Boone Younger and dropping two letters from his first name don't exactly constitute creative inspiration, or even interesting historical revisionism. The premiere tries to [WORD ILLEGIBLE] five minutes worth of aside into a one-hour story; seldom has even a television show been so agonizingly unevenful.

"A Man's gotta finish what he starts out to do," Dan'l tells us at one point. May the finish for his false starter come quickly, like a b'ar in the n'ght. Period. 'Lucan'

ABC's "Lucan" is not really a new fall series, but the show, which had a test run or two last year, has a place in the front ranks of pinch-hitters should another ABC series be canceled. Judging by the one-hour "Lucan" that airs tonight at 8, we should all hope that no vacancies occur.

Lucan is a 20-year-old kid in an aviator jacket who spent his youth running wild in, we are told, the deepest jungles of Minnesota. Now he lives in a room at the zoo and spends his spare hours helping folks in jeopardy. Tonight he chaperones a cute Bulgarian gymnast who a couple of fatsos tirelessly endeavor to kidnap.

It is hard to believe so little can happen in an entire hour. Mostly, Lucan runs - and not on all fours, either - and runs and runs. Occasionally he looks tenderly into those Bulgarian eyes and in the last scene, when the girl is on her way back toward the Iron Curtain. Lucan takes to the runway and howls at the 707 flying overhead. The call of the wild never sounded tamer.

There is almost no violence in "Lucan," to conform to the new network standards, and that might be commendable except that the writers have come up with nothing to put in its place. Kevin Brophy as Lucan dashes with agility, stares with intensity, and proves he can catch a cab, literally. But if this kind of vacuum can pass for entertainment, we really are the most bored society in the history of civilization.