While on a VFR cross country flight the airplane sustained a total loss of engine power due to fuel exhaustion. During the ensuing emergency landing to the level, sage brush covered, open desert terrain, the pilot failed to maintain the recommended glide airspeed and stalled the airplane. The investigation determined that on the evening prior to departing on the accident flight the pilot filled the fuel tanks with 19 gallons of fuel which brought both tanks to about 3/4 full. The fuel tanks contained about 29.25 gallons of fuel. The pilot did not visually check the fuel tank level prior to departing on the accident flight. The engine, airframe and engine fuel system examination did not disclose any preexisting malfunctions or failures and the cause of the fuel exhaustion could not be determined. The airplane's owners manual indicates that the fuel endurance range with 29.25 gallons of fuel should have been about 4 hours and 52 minutes at 75% power.