LOCUST 181 



Color ? How far does it extend ? Does it give 

 off branches ? 



c. The abdominal muscles. — Some can be seen only- 



after the removal of the digestive and reproduc- 

 tive organs. Position ? Arrangement ? In what 

 direction do their fibres run? Color? Attach- 

 ments ? Put a small piece of muscle tissue into 

 a drop of normal salt solution and examine under 

 the high power. What is the microscopic struct- 

 ure of the insect's muscle ? 



d. The •wing muscles. — Position ? Arrangement ? 



Number ? Direction of fibres ? To what are they 

 attached at each end ? How are those on oppo- 

 site sides of the body separated from each other? 

 Is there any such separation between the wing 

 muscles and the abdominal muscles ? 

 Lying beneath the abdominal muscles find 



e. The corpus adiposum. — "What part of the body 



does it occupy % Structure ? Color ? Examine 

 some of it under a low power. 



/. The tracheae. — If a recently killed specimen be 

 placed in water the tracheae will appear as delicate, 

 glistening white tubes. What is their relation to 

 the spiracles ? Position ? Shape ? Make out if pos- 

 sible six longitudinal tracheae: two spiracular, two 

 dorsal, two ventral. Examine some of them under 

 a low power and note their structure. Are they 

 open or closed ? If open, what keeps them so ? 



With the fine forceps pick away all of the mus- 

 cles in the thorax and abdomen and find 



g. The Digestive System. 



It consists of the following parts in order, pro- 

 ceeding from before backward : 



