Eggs are laid in each cell as soon as the walls have been partly built. The egg is attached to one of the angles of the cell towards the centre of the comb; rarely is the egg attached to the base of the cell. The larva hatches from the egg in about 6-8 days.
The right photo shows a series of larval cells with larvae at different stages of development.
The larva grows by a series of 'stages' or 'instars'. To accommodate its increasing size, the larva sheds its skin at the end of each instar and grows a new and larger one for the following growth stage. Five instars are completed before the larva encases itself in a cocoon. (The left photo, with the side of the cell cut away, shows two larval cells with developing larvae.)
The larvae are fed and checked by 'nursing' adult workers 50-80 times each hour. Total larval development time is 9-22 days depending on the temperature and availability of food.
When fully fed, the larva spins a cocoon within its cell using silk secreted by its salivary glands.
Inside this cocoon the larva develops into an adult (metamorphosis). During this time (7-9 days) the pupa is not tended by adult workers.
Both worker and queen larval/pupal cells are produced. The queen pupal cells are much larger than worker cells.
When fully developed the adult cuts away the cap of the cell and pulls itself onto the surface of the comb.
In order for the colony to survive, the adult workers must perform a large number of tasks both inside and outside the nest. Workers start as nurse wasps, then progress to the collection of nesting materials and fluids and then to foraging for solid foods for the larvae; the older wasps guard the nest entrance. Workers wasps live only several weeks.