“A nice old greybeard” – Friedrich Ris’ correspondence archived at the Senckenberg Museum Frankfurt/Main, Germany

The private papers of Friedrich Ris including letters he received were digitized and perused. Altogether 1635 letters written by 118 correspondents are considered, and their content is summarized. In addition 14 letters sent to Ris’ relatives after his death are included. The correspondence covers the 53 years from 28-xii-1884 to 28-i-1931. Generally the correspondence involves an exchange of expertise, publications, illustrations, photographs, and to some extent private matters. Also the selling of specimens is mentioned in some letters. During the First World War Ris, a neutral Swiss citizen, corresponded with several entomologists from warring nations on both sides of the conflict. The lack of letters from Förster and Krüger is discussed. The correspondence resulted in the discovery of some Odonata specimens captured by Bartenev. Calopteryx splendens was a species of special interest to Ris, he requested specimens from several correspondents at least after 1912. There is evidence for the deposition of the holotype of Selysiothemis nigra in Selys’ collection. Furthermore the correspondence provides information e.g. about the exchange of type material, the discovery of new species, the extensive collecting of [E.B.] Williamson, of different points of view regarding the correct spelling of Aeshna, and further odonatological topics. Apparently unpublished data found in the correspondence are the first records of Lestes macrostigma at the Lake Neusiedl, Austria in 1923 by Zerny, and the quantities of Somatochlora arctica captured by Morton during his 1904 trip to Switzerland. Probably the earliest photographs of water mites on the wings of Sympetrum meridionale were found in Ris manuscripts responding to a letter of Viets.