156 INVERTEBRATE ANIMALS. 



The most destructive species is the Migratory Locust 

 {Acrydium migratorium. Fig. 67), which is very abundant in 

 Africa, India, and throughout the whole of the East. Owing 

 to the rapidity with which they devour every thing they can 

 possibly eat, and owing to their enormous numbers, the Lo- 

 custs are compelled to be constantly on the move, looking for 

 "fresh fields and pastures new." It is from these migrations 



!FiG. 67. — The Migratory Locust {Acrydvwm niiffratorium). 



in vast bodies in search of food that the Migratory Locust 

 takes its name. When one of these destructive hosts visits 

 a district, it only needs a few hours to convert the most fer- 

 tile country into a howling wilderness. In an incredibly short 

 space of time, every green thing on their line of march is 

 destroyed, every leaf is stripped from every tree, every blade 

 of grass and corn is eaten down, and it is not until the ground 

 is utterly bare and brown that the locusts take wing and seek 

 out some fresh region to devastate. 



Oedee VI. Neueopteea (Gr. neuron, nerve; pteron, 

 wing). — The mouth in this order is fitted for mastication; the 

 wings are four in number, generally nearly equal in size, all 

 membranous, and traversed by numerous delicate nervures, 

 which interlace so as to form a delicate net-work (Fig. 68). 

 The metamorphosis is generally incomplete, but is sometimes 

 complete. 



This order includes the well-known and rapacious Dragon- 

 flies {LibellulidoB), the Caddis-flies {Phryganeidm), the May- 

 flies {JSphetneridm), the Ant-lion {Myrmeleo), the Aphis-lion 

 (Fig. 68), Termites, etc. The last of these — namely, the Ter- 

 mites or white ants — are social insects, living in organized 

 communities, and exhibiting many remarkable phenomena. 

 They are mostly inhabitants of hot countries, and cause im- 

 mense mischief by destroying wood-work of all descriptions. 



