The time has come for Mayor Wagner to issue a proclamation honoring the Second City troupe.  In view of its five previous revues and "Open Season at Second City," which opened last night at Square East, 15 West Fourth Street, it would not be out of order for the Mayor to proclaim something like; If You Want to See a Wonderfully Wacky Show, Go to Second City Week.  If Mr. Wagner hasn't got a spare week around, let us all implore him to find one.

Six gloriously gifted entertainers have put together blackouts and skits that are wildly funny.  In alphabetical order, Severn Darden, Bob Dishy, Barbara Harris and three recent additions to the company -- Ben Keller, Dick Schaal and Avery Schreiber -- are irresistible.  Even when the material thins, it is a blessing because it gives you a chance to rest from laughing.

Perhaps the most hilarious segment involves Mr. Dishy and Mr. Schaal as weary truck drivers trying to keep awake on a long, long trip.  "My eyes are O.K.  It's the lids that are tired."  Mr. Dishy, who is at the wheel, insists.  Watching him drive, eat a sandwich, smoke a cigarette and drink beer almost simultaneously is pure joy.

The company asks questions like: Will the North and South ever be able to communicate? Mr. Dishy, representing the North, visits a diner in the South.  The waitress is Miss Harris, with a Southern accent.  To give you an idea what goes on, Mr. Dishy starts by saying he'd like a bowl of alphabet soup -- without the O's.  "I can't eat O's, he says, wide-eyed.  "They don't agree with me."

A brief attempt at an opera called "The Applicant" fizzles.  It is nearly redeemed by Mr. Schreiber, although it is unlikely he'll become a member of the Metropolitan Opera company.

Other targets include the Kabuki theater, voting machines, philosophy professors and aid to South Vietnam.

Paul Sills nd Arnold Weinstein have staged the show, which was created by the performers, imaginatively.  Tom O'Horgan composed the music and plays it well, too, on the harp, piano and other instruments.

Even when the players are improvising a folk song from words supplied by the audience, they are inventive.  The song emerges delightfully as "Fixing Pipes in the Billiard Room." Fa-la-la-la-la, la-la-la-la-la.

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