THE LOCUST OR THE CRAYFISH. 59 



they have a sense of touch. Of hearing. Of tem- 

 perature. 



Assuming that they have these various senses, can 

 you determine which he uses in the selection of his 

 foods? Which does he depend upon most in taking 

 care of himself; for example, in escaping you when 

 you are trying to capture him? 



b. Can you discover by observation and experiment 

 the range of their food? What do they prefer? 

 Have they anything like hunger? How do you 

 judge? Watch the feeding process carefully and 

 describe the natural position which the locust takes 

 in reference to its food and the mode of action of 

 the mouth parts. Notice the secretion ("saliva") 

 that escapes from the mouth when the insect is 

 handled. 



c. Study more carefully the locomotion, and the exact 

 method of* accomplishing it. Just how are the 

 various appendages used in the process? To what 

 extent do the various parts of the body move in 

 relation to each other? To what extent the various 

 segments of the appendages? 



Do you find any motions that you would be disposed 

 to class as "breathing" motions? What evidences 

 would you advance that they are respiratory? 

 Where are the motions located? Can you discover 

 any organs by which the air might enter the body? 

 Count the motions per minute, both before and 

 after a long flight. 



Find some way to measure the strength of the 

 action of the jumping legs. 



