70 



APPLIED ENTOMOLOGY 



The bodies of dragon-flies are often brilliantly colored, and in some 

 cases covered with a " bloom," giving them a whitish appearance (Fig. 

 41). The adults feed on practically almost any flying insects smaller 

 than themselves which they may capture during their flight. Flies and 



i 



FIG. 41. Dragon-fly (Plathemis lydia Dru.) showing "bloom" on abdomen. About 



natural size. (Original.) 



mosquitoes form a favorite food, and the attempt has been made to 

 "tame" dragon-flies and keep them in houses on this account, but with- 

 out success. They, are very voracious, one specimen having been known 

 to consume 40 house-flies in less than two hours. 



Many dragon-flies fly very swiftly either in direct lines or making 

 sudden changes of direction while hunting their prey, and are perhaps 



FIG. 42. Nymph of a Dragon-fly with mask extended forward. 



(Original.) 



Enlarged one-third. 



unequalled in this regard by any other insects. They also mate in the 

 air. The eggs are laid either in the water, attached to water plants, or 

 in the stems of plants under water. In the latter case they are laid singly 

 but otherwise they are usually in clusters containing either a small or a 

 large number of eggs. 



The eggs may hatch after a few days, or if laid in the fall, may not 

 produce nymphs until the following spring. The young nymphs stay 



