The Lepidoptera collection was accumulated largely by W.W. Newcomb and Sherman Moore and consists of a very complete collection of Great Lakes species and an average collection of exotics obtained by them through purchases or exchanges. Particularly noteworthy are the collections of microlepidoptera from Ralph Beebe and tropical collections from Marston Bates. The Division also holds a good collection of tropical Satyridae donated by W.F. Lawler. More recently, the curation of the Lepidoptera has been improved by talented associates from the Biology Department including W.H. Wagner, Jr., Brian Scholtens and Robert Raguso. The museum has a general representation of orders and families of spiders and other arachnids, and Myriapoda.
Most spiders are from the Great Lakes region, with a small number of exotics.
The recently acquired Malaysian malaise trap residues have yielded numerous spider specimens. The myriapod collection includes specimens from Mexico, Central America and the Philippines in addition to North America. The museum holds a large collection of Acari, among the five largest university collections in the United States. The slide collection contains a general representation of essentially all families except Oribatei and water-mites. The collection of Astigmata built by OConnor has the broadest taxonomic scope of any North American collection.