The collection includes a large number of insects and spiders. The main collections are the Lepidoptera collection (among others Maassen, Lücker, Rootbeen, Baltus), Erich Wasmann’s collection of Formicidae, Isoptera, myrmecophiles and termitophiles, and the Coleoptera collection (for example Poot). Indigenous material was mostly collected in Limburg (Southern Netherlands
), foreign material was either collected by collectors who left their collections to the NHMM or it was sent to them because of their recognised expertise in their field or as exchange material.
Most of the material in the collection was collected in the twentieth century, though the Wasmann collection (not yet digitized) also contains a significant amount of 19th century material.