My last group of nests are built of paper, which the wasps create by chewing wood fibre into pulp. So in the Three Little Pig story they are the house of wood or sticks!
Hornets and paper wasps are eusocial* insects, and live in large colonies. In Assam, I found this hornet nest, probably Vespa analis judging by the beautifully scalloped pattern of the nest; the huge nest dwarfs the hornet in the middle, and must contain a sizable colony:
The next photo is the nest of Maine’s Bald-Faced Hornet, Dolichovespula maculata, not quite as big, but still a very respectably sized abode. They can reach two feet tall, and contain up to 700 workers:
They are intricate constructions. The outer case is layer upon layer of paper, like a mille-feuille pastry.
The outer layer conceals tiers of honeycomb chambers. This disembowelled one was in a lilac bush in my garden, and its inhabitants were responsible for a nasty sting which blew up one side of my face to unattractive proportions last summer.
The nests are built freshly every year, so taking one apart during the winter in the interest of science is OK, and also safe (post-frost) because only the fertilized queen survives the winter, and she hibernates elsewhere .
The Northern Paper Wasp, Polistes fuscatus, builds a smaller nest, and the cells are exposed, like this one under the eaves of our cottage. They are not very aggressive, and you can watch them at work, from a safe distance.
The queen lays a single egg in each cell. The developing larva is fed by the workers with such delicacies as masticated caterpillars. If you look carefully, you can see the light brown larvae in two of the cells near the bottom left of the photo below, and in the cells a little higher up there is a greenish sludge that I think is caterpillar puree.
When the larva is fully developed it spins a silken cream-colored lid for its cell, beneath which it pupates. You can see one in the centre of the photo above. Soon after, a new wasp emerges from the pupa, cuts off the lid, and crawls out into the world.
* Eusocial insects show an advanced level of social organization, in which a single female or caste produces the offspring and nonreproductive individuals cooperate in caring for the young.