On Lame's equation of a particular kind

It is shown that the Lame's equation ${d^{2}\over d z^{2}}X+\kappa^{2} cn^{2}(z, {1\over \sqrt 2})X=0$ can be reduced to the hyper-geometric equation. The characteristic exponents of this equation are expressed in terms of elementary functions of the parameter $\kappa$. An analytical condition for parametric amplification is obtained.