Now, one whole week into autumn, we can at last abandon such summer activities as inviting friends in to watch our air conditioner or laying bets on whose dish of chocolate-chip ice cream will melt first.

Farewell to our lazy, heat-wracked selves. It is time to leap into a Chorus Jig, catch a Birdie in the Cage, and -- heavenly precursor of cold -- dance a Crooked Stove Pipe.

It is time to give a square dance.

The first problem you will face is trying to think of your friends as groups of 8; you must invite 8 friends, 16 friends, 24 friends, though once you have 24 square dancers on the floor, you can probably invite a few extras: fill-ins for the fallouts.

The next problem is to find a space big enough for everyone to do-si-do, allemande left and swing their partner without bashing into each other and everything else. And lastly, you need a leader, someone to tell you what to do.

Since Agnes DeMille's "Rodeo," people have tended to think of square dancing as performed by ladies in flouncy petticoats and gentlemen whose red faces were matched by the Western red bandana around their necks. And there's no reason why you can't have a Western-style square dance, but square dancing is simply a variant on the old country dances, the contra or long dances and round dances of an earlier time.

The caller will set the style for the evening and there are two definite schools: traditional and Western. Traditional callers use figures that predate the 1930s, basic dances which people can memorize. The Western style teaches the movement -- back and forth, or join hands and circle right -- rather than the whole dance; it is the caller who dictates the patterns.

Two callers who can arrange an evening of traditional dance, with its accompaniment of fiddle, banjo, guitar and sometimes piano, are Bruce Strand (243-8036) and Lou Shapiro (636-7125). Shapiro also can put you in touch with other callers. Prices vary according to distance traveled, music, time, etc., and must be worked out with the individual callers.

Eben Jenkins, who heads the Square Dance Callers Service of Maryland, will call a Western-style dance, or put you in touch with other Western-style callers.His basic rate for two hours, based on no more than 15 miles travel, adults only, and no alcohol, is $50. He also provides records of square dance music and a phonograph. For information on callers, or on classes, contact Jenkins or his wife Mary: 434-6666.