Northern Arizona University Walnut Canyon National Monument Collection (NAU-WACA) is an important collection of both specimens and associated images of arthropods within Walnut Canyon National Monument on the Colorado Plateau. The goal of the WACA collection, on behalf of the National Park Service and NAU, is to represent material relevant to ecologists, taxonomists, conservationists and the public. Mark Szydlo Biologist for the National Park Service, and Gary Alpert, Biologist at Northern Arizona University have been contributing specimens for curation into this collection.