Cretaceous stick insect fossil mimics Ginkgo foliage
It is the earliest known example of stick insect mimicry.
This insect mimics the leaves of Membranifolia admirabilis, related to Ginkgo biloba which was common then, but is extinct today. The dark straight veins in the wings in this fossil, when the wings are folded over the back, closely resembled M. admirabilis.
The insect evolved to look like these leaves, including their shade of green, and concealed itself from predators by blending in the foliage.
Images and free article from PLOS ONE: Under cover at pre-angiosperm times: a cloaked Phasmatodean insect from the early Cretaceous Jehol biota. Wang M, Béthoux O, Bradler S, Jacques FMB, Cui Y, et al. (March 19, 2014).
PLOS ONE 9(3): e91290. doi:10.1371/journal.pone.0091290.