98 FIRST LESSONS IN ZOOLOGY. 



mimic leaves and sticks, so that birds are deceived by 

 them. 



^Locusts are also attacked by parasites: little red mites 

 stick to their bodies; hair-worms, and especially the mag- 

 got of the flesh-fly, infest them, and thus thousands of them 

 are swept away. All this is of use, however, for were it 

 not for the kindly aid thus rendered in nature, the earth 

 would be each year overrun with locusts. 



Fig. 98 illustrates the incomplete metamorphosis of the 

 locust: 1, side view, and la, dorsal view, represent the fresh- 

 ly hatched larva ; 2, the larva after its first moult ; 2b, the 

 three thoracic segments seen from above, there being no 

 rudiments of wings; 3, 4, and 5 represent the three pupal 

 stages; the rudimentary wings becoming larger at each 

 moult, until, after the fourth moult, the wings attain their 

 full size, as at 6 and 6", when the insect is fully grown. 



Besides the common black cricket, the green tree-cricket 

 is very common. The males alone make the loud shrill 

 noise so constantly heard late in summer; while the females 

 bore into the branches of vines and shrubs for the purpose 

 of laying their eggs. 



In the cockroach the body is much flattened, so that it 

 can hide by day in cracks or under stones. 



To the Orthoptera also belong the Mantis and the "Stick- 

 bug," which is wingless, and mimics sticks and stems of 

 leaves. 



The Orthoptera are so called because in the grasshoppers 

 and locusts the fore wings are more or less narrow and 

 straight. 



