Hearn studied and wrote extensively on insects.[5] The last section of Kwaidan contains three essays on insects and their connection to Chinese and Japanese beliefs.[6]
- Butterflies: Personification of the human soul.
- Mosquitoes: Karmic reincarnation of jealous or greedy people in the form of Jiki-ketsu-gaki or "blood-drinking pretas".
- Ants: Mankind's superior in terms of chastity, ethics, social structure, longevity and evolution.