122 



THE VITAL FUNCTIOMS. 



viriclisslma, or common grasshopper, are deli- 

 neated in their relative situations, but detached 

 from one another, in Fig. 267. The upper jaws 

 (m), which are termed the mandibles^ are those 



principally employed for the mastication of hard 

 substances ; they are accordingly of greater 

 strength than the lower jaws, and their edges 

 are generally deeply serrated, so as to act like 

 teeth in dividing and bruising the food. Some of 

 these teeth are pointed, others wedge-shaped, and 

 others broad, like grinders ; their form being in 

 each particular case adapted to the mechanical 

 texture of the substances to which they are 

 designed to be applied. Thus the mandibles 

 of some MelolonthcB have a projection, rendered 

 rough by numerous deep transverse furrows, 

 converting it into a file for wearing down the 



I 



