- Only major entomological collection in state of Iowa.
- Primary source of historical specimens from prairie habitats of Iowa & upper Midwest
- Significant collections by H.H. Knight, J.A. Slater, and H.M Harris (Hemiptera), J.L. Laffoon and W.A. Rowley (Diptera), and G.W. Courtney (Dipteraandaquatic insects)
- Significant international collections from Asia (especially India, Nepal, and Thailand), Central America (especially Costa Rica), South America (especially Chile) and Australia
- Important global holdings for taxa of prior and current research focus (e.g., Miridae, Blephariceridae, and Mycetophilidae)