8 PRACTICAL ZOOLOGY. 



the centre of the larger veins, and give air to the 

 blood as it flows. 



8. The nervous system of the grasshopper consists mainly 

 of a white cord extending along the floor of the whole 

 body cavity. In most of the abdominal rings the 

 nerve cord has enlargements called ganglia, from 

 which nerves branch to the surrounding parts. 



THE DEVELOPMENT OF THE GRASSHOPPER. 



The egg hatches out a little grasshopper, at first with- 

 out wings. As it grows, it sheds its skin (moults) several 

 times. In moulting, the skin splits along the back of the 

 head and thorax, and the insect works its way out. At 

 first the newly hatched insect is very soft ; the writer has 

 seen a grasshopper bend its tibia double in the effort of 

 pulling out of the old skin; but the tibia soon straight- 

 ened and hardened, showing no signs of injury. 



For descriptions of the grasshopper, see Packard's " Zool- 

 ogy," Packard's " Guide to the Study of Insects," Brooks' 

 " Handbook of Invertebrate Zoology," " The Rocky Moun- 

 tain Locust," in First Annual Report of U.S. Entomologi- 

 cal Commission, 1877 (issued 1878), Comstock's " Guide 

 to Practical Work in Elementary Entomology." 



GRASSHOPPER CARD. 



Take a card six inches by four. Make a faint mark 

 lengthwise in the middle to aid in placing the parts sym- 

 metrically. Separate the parts of the grasshopper, and 

 paste them on the card in their proper order. Before be- 

 ginning, plan the whole arrangement. First, cut off the 

 head ; leaving a central place for the head, remove the 

 mouth parts, pasting each to the card as it is removed. 



