The author presents a series of illustrated essays on insects and small animals that infest human environments, combining natural-history description, life cycles, anatomy, habits, and practical notes on their economic and hygienic impacts. Chapters focus on cockroaches, various mosquitos including the anopheline and yellow-fever types, bot or warble flies, the biscuit weevil, fig moths, stable-flies, rats and field mice, using diagrams, observational anecdotes and occasional wry commentary to explain identification, development stages and interactions with people and livestock.