  As was shown recently, non-Abelian vortex strings supported in
four-dimensional ${\cal N}=2$ supersymmetric QCD with the U(2) gauge group and
$N_f=4$ quark multiplets (flavors) become critical superstrings. In addition to
the translational moduli non-Abelian strings under consideration carry six
orientational and size moduli. Together they form a ten-dimensional target
space required for a superstring to be critical. The target space of the string
sigma model is a product of the flat four-dimensional space and a Calabi-Yau
non-compact threefold, namely, the conifold. We study closed string states
which emerge in four dimensions (4D) and identify them with hadrons of
four-dimensional ${\cal N}=2$ QCD. One massless state was found previously: it
emerges as a massless hypermultiplet associated with the deformation of the
complex structure of the conifold. In this paper we find a number of massive
states. To this end we exploit the approach used in LST, "Little String
Theory," namely equivalence between the critical string on the conifold and
non-critical $c=1$ string with the Liouville field and a compact scalar at the
self-dual radius. The states we find carry "baryonic" charge (its definition
differs from standard). We interpret them as "monopole necklaces" formed (at
strong coupling) by the closed string with confined monopoles attached.
