"Supplement to Harvesting Ants and Trap-Door Spiders" by J. Traherne Moggridge is a scientific publication written in the late 19th century. The work serves as an addition to his earlier observations on the behaviors and habitats of harvesting ants and trap-door spiders, expanding the discussion on specific species and their ecological roles. The book focuses on the intricate lives of these insects, emphasizing their characteristics, behaviors, and relationships with their environments, as well as featuring specific descriptions of various spider species provided by Rev. O. Pickard-Cambridge. At the start of the publication, Moggridge reflects on the continued research that has enhanced understanding of both harvesting ants and trap-door spiders since his initial work. He emphasizes the importance of collaboration among naturalists and encourages the sharing of discoveries to further enrich the knowledge surrounding these creatures. He records various observations from locations like Cadenabbia and Montpellier, detailing the species of harvesting ants identified in those regions. Establishing a foundation for the extensive scientific inquiry that follows, he highlights the behaviors of these ants, such as their food-storing habits, while also posing questions intended to stimulate future exploration into the lives of both ants and spiders. (This is an automatically generated summary.)