A CHAPTER OF LIFE-HISTORIES. 77 
the surface of the water in the act of depositing eggs. 
These eggs soon hatch into tiny nymphs, which live 
in the water, and, moulting from time to time, produce 
the various sizes found by the collector. 
If we compel a few of these nymphs to go without 
food for a day and then feed them with insects, wé 
shall be able to watch the use of the strange mask 
which hides the face, or perhaps we should say the 
mouth. This mask is really a very strange develop- 
ment of the so-called lower lip, the structure of which 
may be understood by examining one of the nymphs 
and comparing it with the accompanying sketches 
(Fig. 68). After all, it is not so much a mask as a 
Fic. 68.—The Dragon-fly. A, larva; 8, pupa; C, dragon fly emerg- 
ing from pupa-case. 
formidable grasping organ capable of reaching suddenly 
forward, seizing an unsuspecting victim, and dragging 
him back to the hard mandibles. 
