The inelastic interactions of negative pi mesons with protons at 374, 417, and 454 Mev incident pi kinetic energy are studied by measuring the differential distributions of finalstate neutrons. The pi source is an internal target of the Berkeley 184-inch synchrocyclotron. A magnetic beamtransport system momentum-anaiyzes and focuses the pi beam at a liquid hydrogen target located in an adjacent shielded experimental area. The time-of- flight distribution of neutral particles is measured at various laboratorysystem angles between 10 and 65 deg. Neutral particles are detected by observing the charged products of their interactions in plastic scintillator. The time-of- flight information is determined electronically by time-to-height conversion and pulse-height analysis. The time resolution of the total system is 1.0 nsec. Detected neutral particles accompanied by charged particles are separated by the electronic system from those not accompanied by charged particles. Analysis presuming the principal inelastic reactions to be pi /sup -/p yields pi /sup +/ pi /sup -/n and pi /sup -/p yields pi /sup 0/ pi /sup 0/n separates the time-of-flight spectra into gamma rays, neutrons from the reaction pi /sup -/p yields pi /sup 0/n, and inelastic neutrons. Calculated values of the neutron- detection efficiency are used in the …