  We present the results of a search for the production of new particles
decaying into two jets in pbarp collisions at sqrt{s} = 1.8 TeV, using the
DZero 1992-1995 data set corresponding to 109 pb^-1. We exclude at the 95%
confidence level the production of excited quarks (q*) with masses below 775
GeV/c^2, the most restictive limit to date. We also exclude standard-model-like
W' (Z') bosons with masses between 300 and 800 GeV/c^2 (400 and 640 GeV/c^2). A
W' boson with mass $<$ 300 GeV/c^2 has been excluded by previous measurements,
and our lower limit is therefore the most stringent to date.
