282 ELEMENTARY STUDIES IN INSECT LIFE 



With these points clearly in mind, take up the study 

 of the cicada. Pin the head on a piece of cork, with the 

 front of the head upward. With the dissecting-needle 

 carefully draw out the mouth-parts contained in the 

 long tube, the three-jointed labium. Trace these needle- 

 like parts as near to the head as possible. How many 

 of these needle-like parts are there? (See Fig. 214.) 

 Each of these needles passes within the head. The larger 

 ones are the mandibles, the smaller ones are the max- 

 illa^. If a compound microscope is at hand, make an 

 examination of the tips of a mandible and of a maxilla. 

 These mandibles and maxillae are used, not for biting, 

 but for boring or cutting through the outer layers of 

 trees and plants. It is likely that they also aid in 

 bringing the juices into the esophagus. 



