ODONATA 55 



9. Make slide mounts of the mouthparts, especially the 

 extraordinary labium. Use the smaller nymphs for this, 

 and see that the grasping apparatus at the tip of the labium 

 is well opened out. 



10. Routine (see page 204). 



LA BORA TOR Y PROGRA M 



A. Study the Living Specimens. 



Adult dragonflies are not very manageable indoors. There 

 is little they will do besides hanging to the wall of a cage. 

 But their nymphs are excellent subjects for indoor observa- 

 tion. Observe: 



I. Their locomotion. They climb, they sprawl or they 

 burrow, according to the equipment of their bodies; but 

 whether endowed with parts suited to one purpose or to the 

 other, they mainly sit (or stand) and wait for prey. 



1. Chase them about the dish. Turn them over and see 

 them right themselves. 



2. Observe their swimming by outpush, at the end of the 

 abdomen, of water from the gill chamber. Sediment in 

 the dish will be disturbed and will swirl about with 

 every expulsion that drives the nymph forward. 



3. Hold a copying or indelible pencil close to the tip of 

 the abdomen of a quiet nymph until the color dissolves 

 a little: the color will enable you to watch the slow 

 inflow of water into the gill chamber, and its sudden 

 expulsion in a colorful cloud. 



4. Feed a nymph that has been kept for a day or more 



i* 



Go/ 

 L 1 



