  The semi-classical approximation is an explicit formula of mathematical
physics for the sum of Feynman diagrams with a single circuit.In this paper, we
study the same problem in the setting of modular operads (see dg-ga/9408003);
instead of being a number, the interaction at a vertex of valence n is an
S_n-module.
  As an application, we calculate the S_n-equivariant Hodge polynomials of the
moduli spaces \Mbar_{1,n}.
