In the year 1819 the University of Edinburgh acquired by purchase a large zoological collection from M. Dufresne, of Paris, including a cabinet containing upwards of 12,000 specimens of insects. Some years later (in 1855), when the whole of the University collections were formally transferred to the Science and Art Department, the Dufresne cabinet became public property.

While consulting lately the volume by Godart devoted to the article “Papilio” in the famous Encyclopédie Méthodique, I was surprised to see a reference to the “Dufresne cabinet” in one of the descriptions of new species, and it immediately occurred to me that the specimen in our possession must be the actual “type” of the species, which discovery led me to search carefully through the whole of the volumes devoted to insects in this well-known work, with a view to finding as many types as possible. At the same time, I thought it possible that Olivier, who wrote his great Histoire Naturelle des Insectes—Coléoptères about the same time, might also mention some of Dufresne's specimens, and this I found to be as I had anticipated.