Green Shieldbug Life-cycle Palomena prasina
In common with other Shieldbugs (also Shield Bugs), the Green Shieldbug lays eggs on the underside of a leaf.
The eggs are green when laid and white when the nymphs have hatched.
The first "instar" (stage) is tiny and has a dark brown or dark plum background colour with black thorax (shoulders).
The second instar replaces the plum/brown for green.
Size comparison: with Harlequin Ladybird and with even tinier white spider mite.
The second instar nymph gradually loses the black shoulder mantle, replacing it with green.
Above left is the third instar or form and above right is the fourth. They are shown together in the photo above centre.
More of the fourth form, including green underside.
The final/fifth instar before adulthood is all green (sometimes with some black shading) and has a shoulder mantle like stage curtains (as the wing cases grow).
Links:
Adult Green Shieldbug
Southern Green Shieldbugs