I haven’t looked at these images in a long time. These are pictures of Exallonyx, staphylinid parasitizing Proctotrupidae wasps. I was into trying to rearing these out in college. I would find them by collecting third and final instar larvae in the spring and rearing them out to see if I got any wasps. You’ll see from the images bellow, but the number of individuals are host size dependent, and emerge in a characteristic manner.
I’ve reared three species out on various occasions from 2007-2008 which I’ve uploaded bellow. The first two species emerged from Philonthus larvae and the third from a Platydracus (I’m guessing violaceous since I found it under bark).
Collected 3 individuals from their own subcorticular Philonthus during a field trip to McLean Bogs for a class on insect larvae.
A second species of Exallonyx from another Philonthus at Six Mile Creek, Ithaca, my old hunting ground.
I think this is Platydracus violaceous, the larva was under bark at Six Mile Creek. Unlike Philonthus, this large larva can house multiple individuals of Exallonyx. The larvae all emerge synchronously and orient themselves in the same manner, most notable once they have pupated.
In 2007, I was also able to rear out a Brachonidae from Sepedophilous to pupation, but the adult never successfully emerged. This was unfortunate, since this would have been the first documentation of Brachonidae parasitizing a staphylinid.