238 ] The Wonderful Ways of Insects and Spiders 



Breathing Without Lungs: Insects do not breathe the way we do. 

 If you examine almost any insect closely, you will discover a 

 series of tiny openings along the sides of the body. These are the 

 "spiracles" or breathing holes through which air passes into the 

 insect's body. 



The spiracles lead into a system of thin-walled tubes which 

 distribute the air throughout the body. As the insect's blood 

 comes into contact with these tubes, it becomes purified as your 

 blood does when it bathes the air tubes of your lungs. In the case 

 of grasshoppers and a number of other insects naturalists have 

 discovered that some of the spiracles are used exclusively for 

 inhaling, the others only for exhaling. 



The Delicate Structures of Legs and Wings 



We have already learned that an insect's body has three main 

 parts: the head, the thorax, and the abdomen. Each of these three 

 parts is made up of ringlike segments that have grown together. 

 The thorax, or middle region, is made up of three segments, each 

 bearing a pair of legs. (You will recall that all insects have three 

 pairs of legs.) 



The insect's front legs are attached to the first segment. The 

 front wingsif there are any and the middle legs are attached to 

 the second segment. The hind legs and the hind wings, if they 

 are present are attached to the third segment. 



If you spread apart a grasshopper's four wings, you will find 

 that the upper ones are long and narrow, while the broad lower 

 wings rest, folded like fans, beneath them. If you feel their tex- 

 ture you will discover that the lower pair are far more delicate 

 than the upper wings which protect them. 



Once insects acquire wings they stop growing. You may see 

 little flies and big flies, but they belong to different species; the 

 little ones are never going to "catch up" and be big ones. 



The legs of all insects are jointed and made up of about ten 

 segments though the number and size vary with different kinds 

 of insects. On many insects the last segment bears one or two claws. 



