  Results are presented from a search for events containing an excited lepton
(electron or muon) produced in association with an ordinary lepton of the same
flavor and decaying to a lepton and two hadronic jets. Both the production and
the decay of the excited leptons are assumed to occur via a contact interaction
with a characteristic energy scale $\Lambda$. The branching fraction for the
decay mode under study increases with the mass of the excited lepton and is the
most sensitive channel for very heavy excited leptons. The analysis uses a
sample of proton-proton collisions collected by the CMS experiment at the LHC
at $\sqrt{s} =$ 13 TeV, corresponding to an integrated luminosity of 77.4
fb$^{-1}$. The four-body invariant mass of the two lepton plus two jet system
is used as the primary discriminating variable. No significant excess of events
beyond the expectation for standard model processes is observed. Assuming that
$\Lambda$ is equal to the mass of the excited leptons, excited electrons and
muons with masses below 5.6 and 5.7 TeV, respectively, are excluded at 95%
confidence level. These are the best limits to date.
