I however atm can't find any other info online on them. I'll keep looking.
The female enters the underground paper nests of the common wasp Vespula vulgaris, or the German wasp, Vespula germanica, and lays her eggs. Despite the conspicuous nature of the intruder, the hosts do not appear to register her presence as she makes her way into the otherwise well-guarded nest entrance.
When the eggs hatch, the larvae drop to the bottom of the nest chamber where they feed as scavengers on debris. This may include dead wasp grubs and adults, remains of food brought into the nest by the wasps and other insects living there.
Mature larvae are sometimes on the combs and have been recorded feeding on dead or moribund wasp larvae and pupae which were left in the combs when the nest was abandoned by the wasps in the autumn. Fully grown larvae leave the nest and pupate in the soil below.
If the host nest is in the roof or walls of a house then it is not unusual for the larvae to end up crawling about in the dwelling-space.
Interesting. Since they're not exactly parasites feeding on the live larvae themselves I put " so I hopefully wouldn't mislead anyone. It's funny how the host don't seem to notice their presence. I wonder how that's possible? Do they release some sort of pheromone?
I'd like to find all of this out somehow. I wonder what other Volucella species are like? Since this is a species of hover fly I'm compelled to wonder what other species do.....
I bet that I'll find one that's twisted.....*^^*