A GRASSHOPPER 11 



In the male the ninth and tenth sternites are present, although 

 they may be fused so as to appear as one plate. An additional 

 ventral plate, called the genital plate, forms the posterior extremity 

 of the body. The tenth tergite is very small ; the podical plates 

 and the cerci are large. Beneath the eleventh tergite is the 

 anus. Compare a male with a female abdomen and identify the 

 parts above mentioned. 



On the lateral side of the first abdominal segment note the 

 auditory organ, a large circular opening covered by a membrane. 

 With the aid of a hand lens find the spiracles of the thorax and 

 the abdomen. Ten pairs are present, one pair on the anterior 

 margin of both the meso- and the metathoracic segments, and 

 one pair on each of the eight anterior abdominal segments, that 

 on the first abdominal segment being just within the margin of 

 the auditory organ. 



Exercise l. Spread out and pin down all four wings and draw 

 an outline of the dorsal aspect of the grasshopper on a 

 scale of 2 to 4. Number the thoracic and the abdominal 

 segments, and label all the parts observed. 



Exercise 2. Cut off the wings from the left side of the body 

 and draw an outline of the side view of the thorax and the 

 two anterior abdominal segments on a scale of 5 or 6. 

 Note that both the meso- and the metapleurum are divided 

 by a diagonal suture into two portions. Number the seg- 

 ments and label all the parts. 



Exercise 3. Draw a side view of the posterior end of your 

 specimen (whether male or female) on a scale of 5 or 6, 

 showing accurately the arrangement of all the parts, and 

 label them all. 



Exercise 4. Draw an outline of the ventral surface of the 

 thorax on a scale of 5 or 6. Note the dovetailing of the 

 anterior margin of the metasternum with the posterior 



