  We use the fermion zero-modes in the background of multi-caloron solutions
with non-trivial holonomy as a probe for constituent monopoles. We find in
general indication for an extended structure. However, for well separated
constituents these become point-like. We analyse this in detail for the SU(2)
charge 2 case, where one is able to solve the relevant Nahm equation exactly,
beyond the piecewize constant solutions studied previously. Remarkably the
zero-mode density can be expressed in the high temperature limit as a function
of the conserved quantities that classify the solutions of the Nahm equation.
