The collection houses approximately 5 million specimens representing about 60,000 species with fifty primary types and 1,000 secondary types. More than 10,000 specimens are added to the collection each year. As a large and comprehensive holding of arthropods, predominately insects, in the Southern Rocky Mountains, it is a major resource for regional and national biodiversity investigations. Much of the material has been identified by specialists to the specific level. Examples of the unique quality of material include the aphids, other Homoptera, Coleoptera, Diptera, Hymenoptera, Lepidoptera, and all aquatic orders. It serves as the repository for arthropod inventories of several National Parks including Canyonlands, Great Sand Dunes, Mesa Verde, Rocky Mountain, Dinosaur, and Yucca House and Colorado National Monuments.