Resonant and non-resonant parametric decay instabilities in the region near the lower hybrid resonance have been investigated in a mirror linear device. The identification of the two processes was possible by comparing with theory the experimental value of the ratio omega 0/ omega LH between the pump frequency and the maximum lower hybrid frequency. In connection with the appearance of decay into quasi-modes, electron and ion heating was found. The propagation of the pump and of the decay waves has been also studied. A pattern of trajectories following a 'resonant cone' was found both for the pump and the decay waves. The measured values of the resonant angles show a reasonable agreement with the theory.