  This paper is about the orbifold theory for vertex operator superalgebras.
Given a vertex operator superalgebra V and a finite automorphism group G of V,
we show that the trace functions associated to the twisted sectors are
holomorphic in the upper half plane for any commuting pairs in G under the
C_2-cofinite condition. We also establish that these functions afford a
representation of the full modular group if V is C_2-cofinite and g-rational
for any g in G.
