Using high-resolution pitch angle measurements made by a magnetic focusing electron spectrometer on the S3-3 satellite, angular distributions of 235-keV electrons precipitated in the slot region of the magnetosphere by a ground-based VLF transmitter are compared with the pitch angle distributions that would be produced by various patterns of longitudinal interaction regions. The observed electrons are in the drift loss cone, necessitating the use of a trace-back-to-longitude-of-origin technique coupled with a two-dimensional convolution program describing the response of the electron spectrometer. The data are well fit both with theoretical calculations of ionospheric field intensity patterns above a transmitter and with a similar pattern of received field intensities measured along a traverse in the conjugate region. The agreement between the data and field patterns implies a linear or quasi-linear wave-particle interaction. The energy-frequency relationship between the electrons and the waves implies an interaction region low on the magnetic field line rather than near the equator, as has been determined for similar precipitations in the inner zone. ¿American Geophysical Union 1987