Chapin traveled to Colombia in 1942 to to study and collect local varieties of Coleoptera (focusing on Coccininellidae) and other insects. He spent the majority of his visit at the Instituto de Ciencias Naturales at the Universidad Nacional, working with Dr. L. M. Murillo. The diary is listed chronologically, and entries are by date. He includes details about travel to and from Colombia; visits to local sites; interactions with local officials and colleagues; sites and specimens collected, including at the páramo near Bogotá; the state of beetle collections in Colombia; observations of local daily life; and interactions with friends and his wife. He collected in the vicinity of Bogotá, Medellín, and Cali. Materials compiled include correspondence, official papers, news clippings from Colombian newspapers, and photographs.