THE PARTS OF A LOCUST. 

 LESSON VII. 



THE PARTS OF A LOCUST (CONTINUED). 



The Abdomen. 



The abdomen is that portion of the body which 

 is behind the thorax. In a locust the thorax and ab- 

 domen are so closely connected that it requires care- 

 ful study to determine where one ends and the other 

 begins. 



1. Examine the ventral or belly side of the body 

 and determine which is the first abdominal segment. 

 The front edge of this segment is dovetailed into the 

 metathorax, so that at first sight it appears to be a 

 part of the thorax. 



2. Examine the upper or dorsal part of the first 

 abdominal segment ; this is widely separated from 

 the ventral part by the cavities for the insertion of 

 the hind legs. 



3. Observe the ears ; these are situated one on 

 each side of the first abdominal segment. Each is a 

 large opening in the body wall which is closed by a 

 very delicate membrane (see Fig. 3). Locusts differ 

 from other insects in having ears in this position. 



4. Examine the seven abdominal segments follow- 

 ing the first ; each of these is ringlike in form. 



5. Find the b r eathing holes or spiracles. There 

 is a row of them on each side of the body. The first 

 one on each side that is in the abdomen is just in 

 front of the ear. In the seven following abdominal 

 segments there is one on each side of each segment 

 near the lower front corner of the upper part of the 

 segment. 



