  In this paper we give a necessary and sufficient condition in which a
sequence of Kleinian punctured torus groups converges. This result tells us
that every exotically convergent sequence of Kleinian punctured torus groups is
obtained by the method due to Anderson and Canary. Thus we obtain a complete
description of the set of points at which the space of Kleinian punctured torus
groups self-bumps. We also discuss geometric limits of sequences of Bers
slices.
