  A four dimensional Superstring is constructed starting from a twenty six
dimensional bosonic string. Fermions are introduced by noting the Manselstam's
proof of equivalence of two fermions to one boson in 1+1 dimensions. The action
of the superstring is invariant under SO(6)$\times$ SO(5). It has four bosonic
coordinates and twenty four Majorana fermions of SO(3,1) representing two
transverse modes of super fermions and conformal ghosts (b,c). The super
conformal ghosts ($\beta, \gamma$) are the quanta of an extended Hilbert space
of the remaining longitudinal modes of two superfermions. The massless spectrum
obtained by quantising the action, contain vector mesons which are generators
of the SO(6)$\times$SO(5). Using Wilson loops, this product group is proven to
descend to $Z_3\times SU(3)\times SU(2)\times U(1)$ without breaking
supersymmetry.Thus there are just three generations of quarks and leptons.
