A day or two before the
final metamorphosis the colour and pattern of the adult wing begins to
appear and can be seen in miniature through the pupal case.
The pupal case splits open
behind the head and along sutures marking the front edge of the wing.
The butterfly pulls itself free, carefully drawing its antennae, legs
and wings out.
At this stage the wings
are small, soft, moist and folded and the butterfly either remains clinging
to the pupal case or moves to a suitable position close by where it's wings
can hang downwards to dry.
Blood is pumped from the
body into the wings forcing them to unfold and expand to their full extent.
While still wet they are carefully held apart and are only brought together
The duration of emergence
(eclosion) varies but can take up to two hours at the end of which the
butterfly is ready to make it's first flight.