INSECTA 



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Habits and Habitat. Insects vary in their habitat. Most 

 of them are terrestrial, some are aerial, others are aquatic, a 

 few even being marine, while still others are subterranean. 



Fig. 85. External anatomy of Calopte'nus spre'tus, the head and thorax 

 disjointed: up, Uropatagium ; /, furcula; c, cercus. (Drawn by J. S. 

 Kingsley.) (From Packard's " Zoology," Henry Holt & Co., Publishers.) 



Some are diurnal, as our common butterflies; others are noc- 

 turnal, as the bed-bug; some, crepuscular, as the moths. Some 

 are solitary ; others gregarious, or social, as the ants and bees. 



Plan of Structure (Fig. 85) . The insect body is divided into 

 three well-marked regions the head, thorax, and abdomen. 



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