166 Education through Nature 



wings under a little sheath. The fourth has small wings; 

 after shedding the fifth coat he looks just like his parents. 



About six or eight weeks after hatching the final change 

 is made. The perfect insect comes out of the last shed 

 skin. It has two pairs of wings. Insects only grow during 

 the larval, or caterpillar, state; molting is confined to 

 that period. The young grasshopper develops from the 

 young larvae to the winged adult stage without changing 

 its mode of life. When larvae and pupae they are very 

 greedy; they eat all the time. When they are grown 

 they do not give all their time to eating. 



14. The digestive apparatus of the grasshopper consists 

 of a pharynx, gullet, gizzard, stomach, and intestine. The 

 blood, which is a colorless liquid, circulates on the dorsal 

 side of the body in a long pulsating tube beneath the skin. 

 This dorsal vessel, or heart, as it is called, is open at both 

 ends and divided by valves into compartments, permitting 

 the blood to go forward but not backward. 



The blood enters the cavity of the abdomen, and mingles 

 with the chyle which transudes through the walls of the 

 alimentary canal. This mixed fluid is drawn into the 

 dorsal tube through the valvular openings as it expands, 

 and upon its contraction all the side-valves are closed 

 and the fluid is forced towards the head. Passing out 

 at the front opening it is again diffused among and between 

 the tissues of the body. 



The brain is formed of several ganglia massed together, 

 and lies across the upper side of the throat, just behind 

 the mouth. The main cord lies along the ventral side of the 

 body, with a swelling for each segment; besides this there 

 is a visceral nerve representing in function the sympathetic 

 system of vertebrates. 



The gizzard is lined with horny teeth. The grasshopper 

 has no true liver, but its functions are performed by little 

 cell-masses in the stomach. The kidneys are also groups 

 of tubes. 



15. Respiration is carried on by trachae, a system of 

 tubes opening at the surface by a row of apertures called 

 spiracles generally nine on each side of the thorax and 

 abdomen. Respiration is performed by the movements of 

 the abdomen. These pipes or tubes ramify the most 



