It's something of a feat to have crossed "Monty Python's Flying Circus" with "NBC's Saturday Night" and come up with a tragedy. "Mother's Little Network," pilot for a proposed public-TV satire series airing at 9 o'clock tonight on Channel 26, shows every sign of being a good comedy show except one: It isn't funny.

The sucess of "Groove Tube," "Tunnel Vision," the National Lampoon, and the NBC and Python shows might lead us to believe we are in a satire boom, but "Mother's" is a satire bust. Poorly filmed and performed by hairy zanies at Boston's WGBH (station staff members were hauled out of their offices to provide the laugh track), the half hour is a collection of modular spoofs that hardly ever hits a target.

Television is usually the intended victim, but it always manages to get away. "Bionic Bag Boy" doesn't speak to any key absurdities. "Elite Performance" promises to razz the snooty artsiness of public TV culture shows but instantly degenerates into meaningless slapstick. A mock commercial for "Slice-O-Magic" stoops shamelessly to the obvious, ending in a gush of profuse hand bleeding.

The Python people got away with a great deal of audacious vulgarity partly because they were deriding the whole concept of audacious vulgarity. When Saturday Night's "Not-ready For Prime Time Players" slip into physical shtick, they're often striking a blow against pretentiousness. The attitude of "Mother's Little Network" never allows for this sort of resonance.

Now take the pie. In the right hands, the pie can be a wonderful weapon. Ernie Kovacs was a master of the pie. Even Johnny Carson, though hardly in the same league, has used the pie to good effect. But in the hands of the "Little Network" clowns, a pie is just a pie. And a pie in the face is just a pie in the face.

In fact, the throwing of food is a virtual motif for this show. Food-throwing is the last refuge of the stranded satirist.

The "Mother's Little Network" pilot cost $60,000. Funding came from the National Endowment for the Arts and three others sources. A WGBH spokesman said yesterday public TV stations are very likely to buy a series of 13 of these shows for next season. In a world where such things can happen, satire may have become automatically pointless.