Evolution and Diversity -- Arthropod Evolution -- Insect Diversity -- External Structure -- Systematics and Taxonomy -- Apterygote Hexapods -- Paleoptera -- The Plecopteroid, Blattoid, and Orthopteroid Orders -- The Hemipteroid Orders -- The Panorpoid Orders -- The Remaining Endopterygote Orders -- Anatomy and Physiology -- The Integument -- Sensory Systems -- Nervous and Chemical Integration -- Muscles and Locomotion -- Gas Exchange -- Food Uptake and Utilization -- The Circulatory System -- Nitrogenous Excretion and Salt and Water Balance -- Reproduction and Development -- Reproduction -- Embryonic Development -- Postembryonic Development -- Ecology -- The Abiotic Environment -- The Biotic Environment -- Insects and Humans. Gillott's thorough yet clear writing style continues to keep Entomology near the top of the class as a text for senior undergraduates, and for graduate students and professionals seeking an introduction to specific entomological topics. The author's long-held belief that an introductory entomology course should present a balanced treatment of the subject is reflected in the continued arrangement of the book in four sections: Evolution and Diversity, Anatomy and Physiology, Reproduction and Development, and Ecology. For the third edition, all chapters have been updated. This includes not only the addition of new information and concepts but also the reduction or exclusion of material no longer considered "mainstream", so as to keep the book at a reasonable size. Based on exciting discoveries made during the previous decade, the topics of insect evolutionary relationships, semiochemicals, gas exchange, immune responses (including those of parasites and parasitoids), flight, and the management of pests have received particular attention in the preparation of the third edition. Overall, more than 30 new or significantly revised figures have been incorporated.