“MrDarwin” at Darwinblog has posted a lovely example of insect evolution recently figured out:
If termites have indeed evolved from cockroaches, then we should expect to find transitional living or fossil termite-like cockroaches and cockroach-like termites. In addition, other lines of evidence should be consistent with this relationships. For example, the derived taxa (termites) should not predate their ancestors (cockroaches) in the fossil record. Moreover, the earliest members of the derived group—that is, the ones closest to the evolutionary divergence—should be the most similar to the ancestral group. Finally, the phylogenetic relationships of their symbiotic bacteria and protists, which are utterly dependent upon their hosts for survival, should be similar to the phylogenetic relationships of their hosts.
So far, all of those things have been found, or not found, according to the predictions of evolutionary theory.
Follow this link for more about termites.