  We present a description for amplitude diagrams in maximal supergravities
obtained by dimensional reduction from D=11, derived from a field theory point
of view using the pure spinor formalism. The advantages of this approach are
the manifest supersymmetry present in the formalism, and the limited number of
interaction terms in the action. Furthermore, we investigate the conditions set
by this description in order for amplitudes in maximal supergravity to be
finite in the ultraviolet limit. Typically, there is an upper limit to the
dimension, set by the loop order, which for an arbitrary number of loops is no
larger than two. In four dimensions, the non-renormalisation power of the
formalism fails for the 7-loop contribution to the 4-point amplitude, all of
which is in clear agreement with previous work.
