8 



ANIMAL BIOLOGY 



the sides is expelled at the front of the heart through short 

 blood vessels. There are almost no well-defined blood 

 vessels in the grasshopper, and the blood, after being forced 

 out of the short vessels at the front of the heart, passes into 

 irregular spaces between the tissues and organs of the body 

 until it finds its way back to the heart again, when it is 

 taken in through the lateral openings and sent out on a 

 new journey. In many insects, es- 

 pecially the transparent young or 

 larval stages of aquatic species, it 

 is possible to see the beating of the 

 heart and the flow of blood in the 

 living organism. 



The organs in the grasshopper 

 which correspond in function to the 

 human kidneys and which therefore 

 serve as a means of getting rid of 

 certain waste products in the blood 

 consist of a series of fine thread-like 

 tubules, called Malpighian or urinary 

 tubules, which empty into the intes- 

 tine close to where it joins the 

 stomach. The waste matter col- 

 lected by these tubules therefore 

 passes out of the body with the undigested portions of 

 the food. Other waste products, especially carbon dioxide, 

 are removed by the tracheal tubes. 



The brain of the grasshopper is situated in the upper 

 part of the head above the esophagus. From the brain 

 nerves go to the eyes, ocelli and antennae, and from the 

 lower side a nerve cord passes on either side of the esopha- 

 gus to a nerve mass called the subesophageal ganglion 

 which supplies nerves to the mouth parts. This ganglion 

 is the first of a series of paired ganglia extending along the 



--so 



FIG. 6. -Brain of 

 grasshopper from in 

 front. C, commissures 

 around the esophagus; 

 E, nervous supply of eye; 

 O, nerves to ocelli; SO, 

 subesophageal ganglion. 



