DRAGONFLY NYMPHS 25 



4. Describe the methods of locomotion of the live animal. 

 How many different methods? Describe each. Notes required. 



5. Note the adaptation of the labium (lower lip) for grasp- 

 ing food. Examine preserved specimen and with forceps draw 

 the labium forward to fully extended position. Draw side view 

 and dorsal view of labium, fully extended, X5. 



6. Draw the entire animal, dorsal view, X/}.. Label the 

 head, the thorax (the part bearing the legs), and the abdomen. 



7. Into what kind of an animal does the nymph transform? 

 See demonstration. Notes required. 



8. Define metamorphosis. Notes required. 



9. Consult Hertwig, p. 401, and learn how insects and 

 aquatic insects in particular, breathe. Describe concisely in notes. 

 See charts. Notes required. 



10. The three plate-like gills of the damsel fly nymphs con- 

 tain the air tubes (tracheae), while in the dragon fly nymphs 

 the posterior part of the intestine is modified and contains 

 tracheal filaments. Air and not blood circulates in these tubes, 

 and aerates the tissues. 



II. DAMSEL FLY NYMPH 



1. Describe the habits of the live animal, its methods of 

 locomotion, habit of resting, etc., while in an aquarium. Describe 

 fully. Notes required. 



2. Does the animal feign death? If so, under what condi- 

 tions and for how long? Notes required. 



3. Draw the entire animal X4, dorsal view. 



4. Draw X5, a plate-like gill. 



5. Examine the expanded labium from the side and from 

 the ventral surface. Compare with labium of dragon fly. 



6. Into what kind of an animal does the nymph transform? 

 See demonstration. 



