It is shown that a set of neighbouring quantum states can be orthogonally transformed into a set of classically behaving localized packets, if their wave functions can be fairly well approximated by the WKB-method and if they lie in a dense part of the energy spectrum. The distribution of the points of localization is the same as predicted by classical statistical mechanics. This is proved in one dimension and for a general spherical potential. It enables one to formulate a partly quantum-mechanical and partly classical description with a smooth transition in between. The short-distance correlation function for oppositely charged particles in a plasma is now easily calculated.