In the Naturalis archives there is a handwritten catalogue listing the specimens from the butterfly collection. It was finished in the early 1930’s. It consists of several bundles of loose pieces of paper, hundreds of them, kept tied together with ribbons between cardboard wrappers. Besides its potential historical interest, it is incomplete, unpractical and unsearchable. The taxonomy has changed, many species names are different or synonymized and all drawers have been rearranged. The old catalogue seems quite useless. But is it?
For years, everyone working in the collection noticed a particular little label attached to the oldest specimens that belonged to the RMNH collection (Rijksmuseum van Natuurlijke Historie, now Naturalis). That lable is quite simple, an elongated, thin piece of paper with “Cat. No.” printed on it and a space below filled with a handwritten cipher, a number between 1 and rarely higher than 30. Obviously, it refers to a catalogue, but which one? After some research, I made the connection with the old Lepidoptera catalogue from the archives.
The catalogue’s structure is as follows: for each species (as identified by the curator at the time, that is, somewhere between 1890 and 1930) there is a drawer number – lade – and a list of the specimens in it, with their label data. Each specimen is assigned a number, always starting with 1. This means that the specimens did not receive an unique identification number. Nr. 1 referred to the first specimen of that species in the drawer. Now I can recreate the contents of each drawer as they were arranged in 1930.
Each specimen can be tracked back to that time, for instance to examine its possible type-status (a type specimen is the name-bearing representative of a species). By comparing the labels pinned under the butterfly and the catalogue entry I can check if the labels have been at some point mixed up or removed by mistake (yes, it happens). The old catalogue also allows me to reconstruct the taxonomical system the staff followed, opening doors for future research in the views and expertise present in the museum at that time. In a few cases, the handwritting is recognizable as that of one of the members of the RMNH staff.
There are more than enough reasons not only just to treasure the old catalogue, but also to digitize it in such a way that it is also searchable. Hopefully, we can take on such a project in the near future.