We study orbital integrals and invariant eigendistributions for the symmetric
pair (g,h)=(gl(4,R),gl(2,R)*gl(2,R)). Let q=g/h and let N be the set of
nilpotents of q. We first obtain an asymptotic behavior of orbital integrals
around nonzero semisimple elements of q. We study eigendistributions around
such elements and give an explicit basis of eigendistributions on q-N given by
a locally integrable function on q-N.