  The wings of the giant wasp "Megascolia Procer Javanensis" are opaque and
iridescent. The origin of the blue-green iridescence is studied in detail,
using reflection spectroscopy, scanning electron microscopy and physical
modelling. It is shown that the structure responsible for the iridescence is a
single homogeneous transparent chitin layer covering the whole surface of each
wing. The opacity is essentially due to the presence of melanin in the
stratified medium which forms the mechanical core of the wing.
