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THE INSECTS— ARTHROPODS 



peoples of the world would be without a direct source of food. Fried 

 ants and grasshoppers are widely eaten in India ; fried caterpillars are 

 sold like hot dogs on the streets of some cities in Mexico ; certain African 

 natives eat the large tropical termites with great relish. We could prob- 

 ably continue to live without insects, but our lives would be greatly 

 affected. 



Courtesy General Biological Supply House 



Fig. 15.2. Termite damage to books. In the tropics termites often come out of the 

 walls and eat their way into books. This stack of books has been completely ruined 



by such action. 



Insect Characteristics 



Insects have three distinct body parts, the head, thorax, and abdomen. 

 Embryonic or larval insects resemble annelids in that there are nu- 

 merous body segments which are similar to one another. Larval 

 forms are often called worms because of this resemblance; a caterpillar 

 or a maggot looks more like a worm than an adult insect. However, 

 during a typical insect development the anterior four segments fuse to 

 form the head, the next three form the thorax, and the remainder of the 

 segments form the abdomen. The dividing lines between the segments 

 cannot be seen in the head, are visible as indentations in the chitin sur- 



