76 LIFE STORIES OF AUSTRALIAN INSE(iTS. 



height, is not certain. To obtain air in this jour- 

 ney they fold the wings back and air is enclosed; 

 for one can see the silvery gleam of the air as the in- 

 sects are in the water. The larva is longer than 

 that of the large dragon-fly. The abdomen termin- 

 ates in three external gills or breathing plates lined 

 with treachese or air tubes. 



We watched the nymph of one of these dragon- 

 flies crawl out of the water and prepare to emerge. 

 It pressed its body up towards the head and formed 

 a kind of hump of its head and thorax — the nymph 

 skin split and the adult emerged. The growth of 

 the abdomen was most rapid. In 15 minutes it 

 grew half an inch, and in 35 minutes it was three- 

 quarters of an inch long. 



The body of the adult or imago remained a pale 

 green for some hours, then this colour gradually 

 gave place to a dark brownish-green with trans- 

 verse markings of pale pink on the abdomen. 



