66 MECHANICAL FUNCTIONS. 



sisting of the three segments, figures 50, 51 and 52. 

 The first is called the Prothorax, Fig. 50, to which is 



Fig. 50. 



connected the first pair of legs. The second, Fig. 51 , 



is called the Mesothorax, and gives origin to the second 



Fig. 51. 



pair of legs and the first pair of wings, or the elytra c. 



The third section is the Metathorax, Fig. 52. This 

 part sustains the third pair of legs and the second pair 



Fig. 52. 



of wings, or the wings proper 10. These two last seg- 



How many sections is the trunk of an insect composed of? On what 

 principle are the limbs of insects named 7 What are the names of th 

 different parts of one of these limbs, and what are their relative situa- 

 tions 7 



