At 17:29 PST, a Cessna 172N and a Piper PA-28-140 collided in mid-air while in the traffic pattern at Palm Springs. The two instructors and three students involved were not injured. The Cessna had been cleared for closed right traffic on runway 31R and was in a turn from crosswind to downwind. The Piper had been cleared into the airport traffic area and told to report two miles out on a 45-degree entry to the downwind for runway 31R. The tower controller had advised the Cessna of a Piper inbound from the northwest, and the Piper had been told of two Cessnas in right closed traffic. The Piper failed to make a position report as instructed. The airplanes collided at about 1,500 feet msl opposite the departure end of runway 31R. The Cessnas left wingtip was struck by the propeller and lower engine cowling of the overtaking Piper. The instructor in the Cessna made a forced landing to a sandy wash about 0.75 miles east of the approach end of runway 31R. The Piper landed uneventfully at the airport.