Amateur naturalist and collector of Coleoptera, he passed the latter part of his life in New York City. He was a member of the Academy, and a note in the Minutes announces his death and speaks with enthusiasm of Guex' interest in entomology. At that time his donations to the Entomological Collections were mentioned and over a period of years he had added materially to them. In 1854 he gave 1500 Lepidoptera and later in the same year 17,000 Coleoptera; in 1855 another 1500 specimens from Italy, France and other foreign regions. While the Academy wanted to accept this valuable collection it had no funds with which to have it packed and moved from New York, consequently they asked for contributions from various interested members, the document listing the signatures being included here. Later on, Thomas B. Wilson purchased Guex' papers and letters to accompany the collections of insects. Aside from the series of letters and lists of insects being shipped to Guex and his shipping book listing the names and addresses with a detailed record of the specimens shipped, we have a catalog of his collection. This catalog is contained in five volumes, paged consecutively to 979 pages.