THE COMMON RED~LEGGED GRASSHOPPER 11 



of muscles and movements of the various organs, or of the 

 body as a whole. 



The largest ganglion is in the head, and is generally called 

 the " brain," or, because of its position just above the esoph- 

 agus, the supraesophageal ganglion (Fig. 3). From this 

 ganglion pass the nerves which go to the eyes, antennae, and 

 labrum. Two cords encircling the esophagus pass to the 

 next ganglion, which, owing to its position just beneath the 

 esophagus, is called the subesophageal ganglion (Fig. 3). 

 This ganglion sends nerves to the mandibles and maxillae. 

 The supraesophageal and the subesophageal ganglia preside 

 over and coordinate the various general movements of the 

 grasshopper's body. It has been shown that an insect may 

 live for months with the anterior of these ganglia destroyed, 

 if the other is not injured. The insect will feed if food is 

 placed to its mouth, but it loses the power to go in search 

 of food. Of the other ganglia three are in the thorax and 

 five are in the abdomen, forming a median chain resting on 

 the ventral surface of the body cavity. These ganglia are 

 centers for the control of movements and respiration in the 

 somites to which they belong. 



The Muscular System. All the muscles of the body are sup- 

 plied with microscopic nerves. The muscles are attached to 

 the hard covering of the body, and when stimulated by the 

 nervous system they contract, thus moving the part to 

 which they are attached. Though delicate in appearance the 

 muscles are in reality very strong, as may be understood 

 when the activity of the insect is 'considered. 



The Reproductive System. As in most other animals, the 

 union of two dissimilar elements is necessary for the produc- 

 tion of a new grasshopper. These elements are the very 

 small, active sperm cells produced by the male, and the 

 much larger egg cells produced by the female. The repro- 

 ductive cells are produced in special organs called gonads. 



