50x Timelapse movie of Japanese yellow hornets (Vespa simillima xanthoptera, family Vespidae) adding layers of pulp ( or envelope) to their secondary nest beneath the ceiling of an open arbour. Note that as soon as a tiny hole was accidentally made on the envelope from inside (twice @1:51 at the centre of relocated nest and @2:58 to immediate left of the nest entrance), another worker repaired it from outside. As for the internal architecture, they bit off a piece of envelope from inside and recycled the nest material to make cells and combs. I was awe-struck to see their cooperative work without a blueprint and a leader. But you can also see some lazy non-workers resting inside the pocket of developing envelope. Recorded for two days of mid-August 2014 in Japan.