80 INSECTA 



(c) Use? 



(d) Color? 



(8) The Spiracles. 



(a) Number to each segment? 



(b) Total number? 



(c) Use? 



(9) Sketch the abdomen, much enlarged. Name the parts 



present. 



B. Internal Morphology 



Pin a large female insect down in a wax-bottomed pan or on a 

 soft pine board, dorsal side up. Dissect under water. With 

 sharp scissors carefully cut through the body wall of the 

 abdomen and expose the internal organs by removing the upper 

 portion of the body wall. Use a fresh specimen. 



1. The Circulatory System. Cut forward along the dorsal 

 side and find small tubular organ called the heart. 



(1) Trace it. 



(2) Sketch it. 



(3) Plan of grasshopper's circulatory system. 



(a) Any arteries, veins, capillaries? 



(b) Closed or open circulation? 



2. The Respiratory System. 



(1) The air-sacs in grasshoppers are tiny white sacs along 



the sides of the abdomen. 



(a) How many to each segment? Remove the dorsal 



wall and see. 



(b) How many in all? 



(c) Uses? 



(2) The tracheae are white branching tubes. 



(a) How are they connected with the air-sacs? 



(b) Uses? 



(3) Plan of respiratory system. 



(a) Is it connected with the circulatory system? 



(b) If so, how? 



(c) If so, why? 



3. The Reproductive System. 



(1) In a female specimen you will generally find the yellow 

 eggs in rows on each side. 



