SUBROUTINE KNINSP(IK, P4, VERTX, IDTYP, LXYZ, LMFIX, CLASID)
 
C  >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
C   Inserts a particle in the KN list. The track is expressed as a 4-mom
C   + vertex. No covariance matrix is calculated (it is zeroed)
C
C  IK        Integer variable (read)
C            KN track number to store info.
C
C  P4        real array (read)
C            4-momentum
C
C  VERTX     real array (read)
C            (x,y,z) vertex of particle
C
C  IDTYP     Integer variable (read)
C            Particle type
C
C  LXYZ      Logical variable (read)
C            TRUE  ==> position info can be used in fit
C            FALSE ==> position info cannot be used in fit
C            Position info is always stored.
C
C  LMFIX     Logical variable (read)
C            TRUE  ==> mass is fixed (fixed during track updates)
C            FALSE ==> mass is floating
C
C  CLASID    Integer variable (read)
C            User defined ID number (stored in ICLSKN)
C  >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>