This 6 September 2018 video says about itself:
When scientists scanned 35 million-year-old fly pupae, they discovered a hidden intruder—fossilized parasitic wasps.
Out of 1,510 ancient fly pupae that were discovered at a site in France, 55 housed the parasitic invaders. Several species of parasitic wasp injected their eggs into the pupae as the maggots transformed into flies. The wasps hatched inside the fly pupae and ate the young flies. Scientists identified four new wasp species among the cache of fossils.
Read more here.