Hymenoptera, Unterordnung Symphyta
The renowned German reference work The Handbuch der Zoologie/Handbook of Zoology was founded in the 1920's by Professor Willi Kükenthal in Berlin and treated the complete animal kingdom from single cell organisms to mammals in eight thematic volumes: Volume I Protozoa, Porifera, Colenteratea, Mesozoa (1925), Volume II Worms (1933/34), Volume III Arthropoda ex. Insecta (1927/1932), Volume IV Arthopoda: Insecta, Volume ...