  We discuss the effect of the instanton induced, six-fermion effective
Lagrangian on the decays of the lightest scalar mesons in the
diquark--antidiquark picture. This addition allows for a remarkably good
description of light scalar meson decays. The same effective Lagrangian
produces a mixing of the lightest scalars with the positive parity q-qbar
states. Comparing with previous work where the q-qbar mesons are identified
with the nonet at 1200-1700 MeV, we find that the mixing required to fit the
mass spectrum is in good agreement with the instanton coupling obtained from
light scalar decays. A coherent picture of scalar mesons as a mixture of
tetraquark states (dominating in the lightest mesons) and heavy q-qbar states
(dominating in the heavier mesons) emerges.
