Back in May I shared this image of a platygastrid wasp guarding the stink bug eggs into which she had inserted her own eggs:
A few days later, I found a cluster of stink bug eggs that were unattended, but I could tell that they had also been parasitized because they were turning black.
I collected these to see what would emerge, and ten days later I got to watch some little platygastrids chewing their way out.
This wasp’s entire life cycle–egg, larva, pupa, adult–takes place within a single stink bug egg, so the only way to see its immature stages would be to go around slicing open parasitized stink bug eggs.
In addition to the darkened color of the eggshell, you can tell that vacated stink bug eggs have been parasitized by the irregularly chewed exit holes. Stink bugs don’t have chewing mouthparts, so a nymph hatches by popping open a neat circular lid at the top of the egg.
(Added 3/5/2012:) Based on a photo submitted to BugGuide, Ovidiu Popovici thinks these emerging platygastrids belong to a species of Telenomus.