192 NATURE-STUDY 



an adult dragon-fly. But the wings are not yet expanded. 

 They are mere fleshy lumps upon the back. The insect 

 gradually inflates these fleshy masses until they become the 

 beautiful, transparent wings. After waiting a short time for 

 the wings to stiffen, the insect begins its swift, aerial life. 



Empty nymph cases are 

 common sights along 

 ponds and lakes. 



This interesting emer- 

 gence of the dragon-fly 

 from the nymph may be 

 observed by visiting a 

 pond when these insects 

 begin to be abundant. 

 Or, better still, collect 

 some of the nymphs about 

 this time and place them 



FIG. 51. " H alf and Half" Wing of a Hemipterous in the aquarium, and yOU 

 Insect or Bug. ^^ ^ fortunate enOUgh 



(Photomicrograph.) 



to see the whole process in 



the school -room. This development of the dragon-fly is 

 called direct, and is not marked by a dormant period. 



Damsel-flies and May-flies have a similar life history. 



The Electric-Light Bug or Giant Water-bug represents 

 another order. It is found in quiet pools and swamps, on the 

 muddy bottom, or under submerged sticks and stones. At 

 night it often leaves the water and, attracted by the arc lights 

 of the streets, it may often be found in large numbers under 

 the lamps. 



The giant water-bug is one of our largest insects. It is about 

 two inches in length, and is admirably adapted for the study 



