When Johanna Humphrey first saw the evelope on her dining room table, she assumed her husband was about to mail it.

The envelope was imprinted with a business firm's address. It was the kind of envelope that is often supplied by firms that want to make it easy for their customers to send in checks. But when Johanna asked her husband about it, he said he had never seen it before.

The Humphreys thereupon guessed that the envelope must have been brought in and put on the dining room table with the rest of the day's mail, so they opened it. Inside, they found a check written by a man in Bellingham, Wash. The check was made to the order of Safeco, an insurance company with an office in the state of Washington. The address on the printed envelope was, "University Station, P.O. Box 5090, Seattle, Wa. 98105."

The Humphreys have no idea why the envelope was sent from ZIP code 98225 in the state of Washington to ZIP code 22101 in McLean, Va., instead of to ZIP code 98105, Seattle, to which it was addressed. Neither can they figure out why, upon arrival in McLean, the letter was delivered to the Humphrey home, which no more resembles a University Station or a post office box them McLean resembles Seattle.

The Humphreys hope the check will get back to the state of Washington in time to prevent that Bellingham resident's auto insurance from being canceled. But in light of the recent performance of the Swift Couriers, they're not offering to bet on it.