On March 21, 1996, at 1906 central daylight time, a Beech B55B, N8496N, sustained substantial damage during a gear up landing in Manhattan, Kansas. The private pilot reported no injuries. The personal, 14 CFR Part 91 flight originated in Aurora, Illinois about 1630 with a planned destination of Manhattan, Kansas. Visual meteorological conditions prevailed and an IFR flight plan was filed. In his written statement the pilot reported that he canceled instrument flight rules with Kansas City Center when he had his destination airport in sight. He slowed the airplane and performed a "GUMPS" check. He wrote that he "thought the wheels were down at this point." He said he performed another "GUMPS" check on final. He "flared normally and went to idle...touched down, and after 2 seconds the nose dropped, and [the airplane] began to slide." He reported that he returned to the airplane five minutes after the accident and observed the landing gear control handle in an intermediate position between the center and bottom detent. During an interview with a Federal Aviation Administration (FAA) Operations Inspector, the pilot reported that he heard the landing gear warning horn during the flare, but thought it was the stall warning horn. Following the accident, a FAA certified mechanic performed a functional check of the landing gear system. He reported that the landing gear system functioned normally.