Story, first published: John W. Campbell Memorial Anthology (1973)
In a final "City" story, fittingly entitled "Epilog," written thirty years later for a John W. Campbell Memorial Anthology edited by Harry Harrison, Simak returns to the Earth and the faithful robot, Jenkins, who has now become almost human. When the Dogs left for the Cobbly worlds, Jenkins remained at Webster House with its memories. The ants enclosed the world with their building, but left Webster Hill and its adjoining five acres untouched. Jenkins spies a crack in the ants' building. He investigates and finds the ants have all gone. Nothing is left inside the ant's colossal edifice but monstrous ant hills, and on top of each ant hill a strange ornamental cast in the form of a kicking foot.
The Earth is lonely and without living things except for Jenkins and some meadow mice. As Jenkins is speculating on the fate of the ants, a starship lands. The old robot, Andrew, steps out. Andrews invites Jenkins to go with him to the stars where he can be of service again. Sadly, Jenkins leaves, but he cannot forget nor can he say goodbye ... "lf he could only weep, he thought, but a robot cannot weep."
Ewald, Robert J.: When the Fires Burn High and the Wind is from the North, p.48