120 GENERAL BIOLOGY 



the sense organs; (e) the structure of the circulatory, 

 digestive and nervous systems. Which of these animals is 

 the more highly specialized? Is one better adapted to its 

 modes of life than the others? Give reasons for your con- 

 clusions. 



m. Physiology. 



From a study in the field and in the laboratory work out 

 the following activities of the grasshopper. 



1. Movements. Describe the kinds and methods of 

 locomotion. What structural features of the legs are 

 adaptations for leaping? How many times the length of 

 the body may the grasshopper leap? What is the purpose 

 of the hooks on the legs? Are both pairs of wings used for 

 flight? 



2. Sensitiveness. With a bristle touch various parts of 

 the body, including the antennae . Which is the most sensitive 

 part? Does the grasshopper see? What evidence is there 

 of this? Is there any evidence that it hears? 



3. Protection. Has the grasshopper any means of de- 

 fense? Is it protected by color? How does it escape its 

 enemies? 



4. Respiration. Observe the respiratory movements of 

 the abdomen. Knowing the structure of the respiratory 

 system, which is characteristic of all insects, explain why 

 non-poisonous powders may often kill insects. 



5. Nutrition. Place animals in a cage with leaves of grass 

 and other plants. If possible observe the method of using 

 the different mouth parts. By using different kinds of 

 plants it may be possible to determine whether there is any 

 choice of food. 



