For the first time in Europe Japan's national butterfly, the "Japanese Emperor", has given offspring, in Austria's Schoenbrunn Zoo in Vienna. The males are bright blue on the upper side of the wings. The females are bigger, but unimposing and brown. This was made possible by the partnership between the district of Hietzing (13th municipal district of Vienna) and the city of Tamba in the south of the Japanese peninsula of Honschu, which brought several eggs and caterpillars of the butterfly as presents and handed them over to the zoo. The caterpillars pupate next year in June and hatch in July.