CLASS HEXAPODA. 



69 



FIG. 114. 



the Katydids in being of a pale green color. Their 

 peculiar call has given them the popular name of 

 " Quakers:' 



The Locusts have short antennae, and are generally of 

 stronger build than the Grasshoppers. They are often 

 migratory. The Rocky 

 Mountain Locust has re- 

 peatedly laid waste large 

 areas lying west of the 

 Mississippi, a single 

 swarm having been 

 known to destroy the vegetation hundreds of square miles, 

 flying from place to place at a rate of from twenty to 

 thirty miles an hour. The damage done to the Western 

 crops in the years 1874-77 was estimated at one hun- 

 dred millions of dollars. 



C'a Ibp'te nits spre tug. Kocky Mountain Locust. 



FIG. 115. 



ORDER HEMIPTERA (he mlp'te ra). 



To this order belong the true Bugs, insects having the 

 mouth-parts produced into a long sucking 

 proboscis. The wings, as well as other 

 parts of the body, present a great variety 

 of structure. Metamorphosis is incom- 

 plete. 



The common Harvest-fly, improperly 

 called Locust, is one of our largest Bugs, 

 and is familiar to all from its buzzing 

 call, which fills the air during the warmer 

 months.* The female often injures the 



* This apparatus is concealed under two valves in 



the upper part of the abdominal cavity. The membrane 

 Ctca'ila septen'decim. f ., , , , . ., . , .... , ,. .., 



Seventeen-year Cicada. drum-head is thin, brittle, and slightly wrinkled. 



There is a muscle attached to it on the inner side. By 

 contracting this, the drum-head is drawn in, but on relaxing, it springs back of 



