14 INTRODUCTION TO ZOOLOGY. 



The Thorax. 



1. Locate the three parts of the thorax. The front 

 one is the prothorax. This has no wings. The 

 middle one is the mesothorax. The hind one is the 

 metathorax. 



2. Find a small opening just above the second 

 pair of legs. This is a breathing pore, or spiracle. 

 Find another in the soft skin between the pro- and 

 mesothorax. 



3. How does the prothorax differ from the meso- 

 and metathorax? What is the advantage of the con- 

 solidation of the meso- and metathorax? 



The Wings. 



1. Spread out the fore and hind wings on the right 

 side of the body. Draw both in this position. 



2. To what part of the thorax is each wing at- 

 tached ? 



3. Find the veins which constitute the framework 

 of the wings. 



4. State the difference between the fore and the 

 hind wing, with reference to size, shape, color, 

 texture, folding, use, position when at rest and when 

 in motion. 



The Leg's. 



1. Examine one of the hind legs. To what part of 

 the thorax is it attached? 



2. Find a short segment close to the body, the coxa. 



3. Find the large segment (femur). The next seg- 

 ment is the tibia. See the spines behind. What is 

 their use? The end of the leg is the tarsus. How 

 many segments has it? Study the feet. 



4. Examine the joint between the tibia and the 

 femur. Draw the whole leg. 



