EXTERNAL ANATOMY. 



27 



[rig. 3.] 



Diagram illustrating the structural parts of a beetle. 



or breast-plate, aud is divided into three parts, tlie prosternum or fore 

 breast-plate ; the mesosternum or middle breast-plate ; and the metaster- 

 num or hind breast-plate. Each of these parts has a side piece, called 

 the episternum ; so that there is an episternum of the prothorax ; an 

 episternam of the mesothorax ; and an episternum of the metathorax j 

 all of which are labeled in the figure. Directly behind each episternum 

 is a smaller piece called the epimeron. These are indicated in the figure 

 by stars ; three stars marking the epimeron of the prothorax ; two stars 

 the epimeron of the mesothorax j and one star the epimeron of the meta- 



