244 



THE INSECTS 



as the tiny green lice seen swarming on the stems and leaves of the rose 

 and other cultivated plants. They suck the juices from stem and leaf. 

 Plant lice have a remarkable life history. Early in the year eggs develop 

 into wingless females, which produce living young, all females. These in 

 turn reproduce in a similar manner, until the plant on which they live 

 becomes overcrowded and the food supply runs short. Then a genera- 

 tion of winged aphids is produced. These fly away to other plants, and 

 reproduction goes on as before until the approach of cold weather, when 

 males and females appear. Fertilized eggs are then produced which give 

 rise to young the following season. 



The aphids exude from the surface of the body a sweet fluid called 

 honeydew. This is given off in such abundance that it is estimated if an 

 aphid were the size of a cow, it would give two thousand quarts a day. 

 This honeydew is greatly esteemed by other insects, especially the ants. 

 For the purpose of obtaining it, some ants care for the aphids, even pro- 

 viding food and shelter for them. In return the aphid, stimulated by a 

 stroking movem.ent of the antenna of the ant, gives up the honeydew to 

 its protector. 



The Order Neuroptera 



The Dragon Fly. — The dragon fly receives its name because it preys 

 on insects. It eats, when an adult, mosquitoes and other insects which 

 it captures while on the wing. Its four large lacelike wings give it power 



of very rapid flight, while its long 

 narrow body is admirably adapted 

 for the same purpose. The large 

 compound eyes placed at the sides 

 of the head give keen sight. It 

 possesses powerful jaws (almost 

 covered by the upper and lower 

 lips). 



The long, thin abdomen does 

 not contain a sting, contrary to 

 the belief of most children. 

 These insects deposit their eggs 

 in the water, and the fact that 

 they may be often seen with the 

 end of the abdomen curved down 

 under the surface of the water in the act of depositing the eggs has given 

 rise to the belief that they were then engaged in stinging something. The 

 egg hatches into a form of larva called a nymph, which in the dragon fly 

 is characterized by a greatly developed lower lip. When the animal is at 

 rest, the lower lip covers the large biting jaws, which can be extended so 

 as to grasp and hold its prey. The nymphs of the dragon fly take oxygen 

 out of the water by means of giU-like structures placed in the posterior 



Dragon fly. Notice the long abdomen and 

 large compound eyes. 



