EXTERNAL ANATOMY. 
27 
or breast-plate, and is divided into three parts, the prosternum or fore 
breastplate; the mesosternum or middle breast-plate ; and the metaster- 
num or bind breast plate. Each of these parts has a side piece, called 
the episterwum ; so that there is an episternum of the prothorax ; an 
episternum of the mesothorax ; and an episternum of the metathorax; 
all of which are labeled in the figure. Birectly 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 ; and one star the epimeron of the meta- 
