relationship with the Sozialistische Einheitspartei Deutschlands (Socialist Unity Party of Germany, SED) that was the ruling political party of East Germany, as Hennig had repeatedly helped employees of the institute gain employment in the West. 1961 to 1976 In West Berlin, Hennig was given an interim post at the Technische Universität Berlin as Distinguished Professor. He rejected offers from the U.S. Department of Agriculture in Washington, D.C. and an offer made by his friend Elmo Hardy, to become a Research Fellow at the University of Hawaii in Honolulu, citing as reasons that the education of his sons took priority for him, and that he needed to have the "cultural witnesses of the antique Greek-Roman Europe within ready access". He instead decided on a post at the State Museum of Natural History in Stuttgart, where he was given a department for phylogenetic research. In April 1963, he moved to Ludwigsburg-Pflugfelden for this position. The scientific collections of the museum had been provisorily kept in Ludwigsburg and remained here until their re-housing at the new site of the museum at Stuttgart's Löwentor, in 1985. Hennig's works in Stuttgart dealt almost exclusively with taxonomic revisions of Dipterans. For the Stuttgarter Beiträge zur Naturkunde, where he published the majority of his works, he completed 29 issues by the end of his life. Significant are the review articles published in Erwin Lindner's Flies of the Palaearctic Regions and the Handbuch der Zoologie. The cladistic methodology was also represented in several published works, foremost among them the article, Cladistic analysis or cladistic classification? A reply to Ernst Mayr (1974), intended as an internationally accessible reply to the criticism Ernst Mayr had made of Hennig's phylogenetic systematics. Willi Hennig only visited international institutions abroad twice, in spite of receiving many invitations for guest lectures. From 1 September to 30 November 1967, he worked at the Entomology Research Institute at Canada's Department of Agriculture in Ottawa and participated in the International Congress of Entomology in Canberra from 22 to 30 August 1972. With his wife, he also visited Bangkok, New Guinea (where much of Mayr's understanding of bird taxonomy originated) and Singapore on this latter trip. His stay in Canada was also used for visits to various entomological collections in museums of the US, including Cambridge, Chicago, Washington, D.C. and New York, always in the hope of finding further amber inclusions of Dipterans, that featured prominently in his