This collection includes
- illustrations of water bugs
- Illustrations from Freshwater Biological Association's publications
- Photographs of insect wings
- Maps, surveys and field books of lakes in Cumbria
- Scientfic papers, including papers on insects and invertebrates
- Scientific correspondence regarding aquatic insect identification
- Personal letters, including Felix Eugen Fritsch's last letters, letters regarding his role as Deputy Director, and letters referring to and correspondence with William Harold Pearsall.