30 ARTHROPODS 



The Schistocerca americana, the Dissosteira Carolina and 

 some others hibernate through the winter in the adult state 

 and deposit their eggs in the spring. 



Internal Anatomy. — (i) Get for dissection large 

 freshly killed female specimens of the Melanoplus differen- 

 tialis or Schistocerca americana. The largest specimens 

 obtainable will be found most satisfactory. Care should be 

 taken that the specimen be neatly handled and that the 

 parts be removed at the proper time. 



After removing the wings, pin the specimen down on a 

 block, or under water, passing pins through the legs and 

 through the posterior end of the abdomen. With the scis- 

 sors cut through the abdomen on each side at the posterior 

 ends just above the groove in the pleurum and cut forward 

 to the thorax. Lift up the flap thus loosened, being careful 

 not to injure the parts beneath. 



Just under the middle of this flap and generally adhering 

 to it find the small elongated tube, the heart, or dorsal 

 vessel, into which the blood collects from the sides and flows 

 toward the head. 



Below the part removed is a layer of muscles running 

 both transversely and longitudinally. Remove and examine 

 carefully. 



(2) Open the thorax by cutting on the mid-dorsal line 

 up to the head. Pull out the sides and pin them down. 

 Note the strong muscles. Do you find them arranged in 

 bands? Can you trace certain of the muscles to the wings 

 and others to the legs ? How many to each ? What do the 

 muscles seem to be composed of ? 



Note the white flaplike bodies, the air sacs. Do you find 

 them connected in any way with white lines? Follow the 



