CHAPTER IV. 
GRASSHOPPERS AND CRICKETS. 
Directions for Work. Collect full-grown and partly 
grown locusts or grasshoppers. Place some of the 
living insects in tumblers with fresh lettuce-leaves. 
Allow ventilation. Why ? Watch the insects care¬ 
fully and compare with a prepared specimen. In your 
note-book answer the questions below. 
Shape of Body, What is the shape of the body ? 
Are the two sides alike (bilateral symmetry) ? 
Is the skeleton or hard part of the body external or 
internal ? 
The Abdomen. The chief divisions of the body are 
the head, thorax, and abdomen. How many segments 
has the abdomen ? 
Count the segments of the abdomen in several 
specimens. Is the number the same in all cases ? 
Do you find a row of breathing-holes (spiracles) 
along either side of the abdomen ? 
Do you find a ridge running lengthwise along the 
abdomen just below the spiracles ? This ridge repre¬ 
sents the softer parts of the segments. These softer 
portions enable the insect to move the upper and lower 
parts of the segments farther apart to take in air while 
inhaling. When they are brought together again the 
air is expelled. The upper hard part of each segment 
is called the tergum, the under part is the sternum, 
and the more flexible part on either side the pleurum. 
Can you see the movement of the abdomen made by 
breathing ? 
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