These wasps have no wax producing glands and therefore can't construct wax cones. To get round this little problem they held a meeting a few years back now I would imagine. One clever little wasp mentioned his cunning plan to resolve their housing problem. So, using their powerful jaws they scraped wood from bark and fence posts, then they had a jolly good chew whilst mixing it with their saliva, then they spread it out to make the combs, and they have never looked back. Quite an amazing structure don't you think. I don't know how long it takes them to make these nests, this one measures 53cm ( 20") circumfrence.