  Eisenstein series are real analytic functions which play a central role in
spectral theory of the hyperbolic Laplacian. Kronecker limit formulas determine
their connection to modular forms. The main result of this work is Theorem 7.2
in which a Kronecker limit formula for a family of non-congruence subgroups
associated with the Fermat curves is presented. As an application we can
determine the scattering constants for the Fermat curves in Theorem 8.1.
