Decays of the lightest neutralino are studied in R_p-violating models with
operators lambda^{prime} L Q D^c and lambda L L E^c involving third-generation
matter fields and with dominant lambda^{prime} and lambda couplings.
Generalizations to decays of the lightest neutralino induced by subdominant
lambda^{prime} and lambda couplings are straightforward. Decays with the
top-quark among the particles produced are considered, in addition to those
with an almost massless final state. Phenomenological analyses for examples of
both classes of decays are presented. No specific assumption on the composition
of the lightest neutralino is made, and the formulae listed here can be easily
generalized to study decays of heavier neutralinos. It has been recently
pointed out that, for a sizable coupling lambda^{prime}_{333}, tau-sleptons may
be copiously produced at the LHC as single supersymmetric particles, in
association with top- and bottom-quark pairs. This analysis of neutralino
decays is, therefore, a first step towards the reconstruction of the complete
final state produced in this case.Comment: 40 pages, 11 figures, version to appear in JHE