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FIRST BOOK OF ZOOLOGY. 



the water, and in the same manner secure air. So this little 

 tree-hopper, while in the young state sucking the juices of 

 grass, and completely immersed in a watery fluid, may be 

 looked upon as an aquatic larva during this stage. 



Fig. 93.— Grass, with the Froth 

 upon it, a, a, and a Young In- 

 sect exposed at b. 



Fig. 94. — A Portion of a Grass-Stem, with the 

 Young Insects magnified: a, the Insect reach- 

 ing- out the Hinder Part of the Body to secure 

 a Bubble of Air ; &, an Insect allowing a Bub- 

 ble of Air to escape in the Fluid, the dotted line 

 b indicates the bubble; c, the Mouth- parts, like 

 a Sting, piercing the Grass. 



Let the pupils collest and examine this froth, and, by 

 carefully wiping it away, they may expose the young insect 



fastened to the grass. 



93. The insect called the seventeen-year cicada, or seven- 



