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ENTOMOLOGY, &c. 



THE natural history of insects ; that branch of 

 zoology which treats exclusively of insects. 



Insects. 



The bodies of insects are composed of joints and 

 segments. All genuine insects have six legs, a head 

 distinct from their body, and are furnished with two 

 antennae. They are all produced from eggs. Some 

 undergo no metamorphosis, others but a partial 

 change, while the remnant pass through three stages 

 of existence, after emerging from the egg, for which 

 purpose incubation is not necessary. 



Metabolia insects that undergo a metamorphosis. 



Ametabolia insects that do not undergo a meta- 

 morphosis. 



No other animals but those of the insect tribe 

 have more than two eyes. Some of these have four, 

 as the phalangium ; others, as the spider and scor- 

 pion, have eight eyes. 



No organs for the circulation of the blood being 

 provided in insects, respiration must be effected by 

 means totally different from those of the higher classes 

 of the animal creation. 



Among invertebral animals, the power of flight is 

 confined to insects with six feet. 



Vermes (Worms). 



This class comprehends all the annular ringed ani- 

 mals that have no distinct head. 



