The pilot stated that, when he returned to the airport after a local flight, two airplanes were in the traffic pattern and a third airplane was inbound about 10 miles east. To sequence with the two airplanes in the pattern and the third airplane on the extended downwind leg, the pilot did not enter the traffic pattern at the midpoint of the downwind leg, but entered the traffic pattern closer to the approach end of the intended runway. He lowered the flaps, but did not lower the landing gear. He turned onto the base leg, extended full flaps, and then turned onto final approach. While on final approach, the pilot had a sense that the airplane was fast and that the “sight picture” was lower than usual, but he did not detect that the landing gear was retracted or recall hearing the landing gear warning horn. He heard the propeller contact the runway and attempted to lower the landing gear, but it was too late. He heard the landing gear warning horn after the airplane came to rest. Postaccident examination of the airplane revealed that a main stringer and leading edge rib inside the right wing were damaged. The pilot stated that there were no preimpact malfunctions or failures that would have precluded normal operation.