INSECTS NEU110PTERA DIAGRAM 6. 131 



suddenly in a country, driven by the wind. The swarms are so 

 thick as to form a real cloud, which darkens the sky. In a day 

 or two, all the vegetation in the country is devoured ; the ground 

 is covered with these insects ; and the crops are filled with them ; 

 and even should they be driven out to sea and drowned, as 

 sometimes happens, their dead bodies are frequently washed 

 ashore in such quantities as to pollute the air for miles around. 

 When a swarm of locusts descends on a country in this manner 

 before the harvest, they always cause a famine. These insects 

 are eaten in many countries, and it is even said that certain tribes 

 rejoice at their approach, because they are a staple article of food 

 with them. 



ORDER NBUROPTERA. 



The Neuroptera have four wings, which are alike in texture and 

 leave no dust on the fingers when touched. The nervures of their 

 wings are arranged in a kind of network. This is well seen in the 

 dragon-flies which fly round ponds. The Neuroptera have jaws, 

 and undergo a complete metamorphosis. They have no sting, like 

 bees, at the end of the abdomen. 



The Libellulce, or Dragon-flies have a long cylindrical body, and 

 fly with ease. Their larva? and pupse live in water. They 

 abound in ponds and pools. They are carnivorous, and very 

 voracious, and attack other insects, or larger prey, such as 

 tadpoles. These larvae are greyish, or of a dirty white, and 

 almost transparent. At the period of its metamorphosis, the 

 pupa, which much resembles the larva, conies out of the water, 

 climbs on the stalk of a reed, and fixes itself there with the 

 hocks of its legs. Then the skin splits, and the dragon-fly 

 emerges. The empty skin is often found on water plants. The 

 dragon-flies eat small insects, and, like their larvae, devour 



