INSECTS 



6 9 



tongue, usually bathed in saliva, is seen in the lower part of 

 the mouth. Since the grasshopper has no lips, or any way 

 of producing suction, it must lap the dew in drinking. Does 

 it merely break off bits of a grass blade, or does it chew ? 



The heart, circulation, nervous system, digestive and res- 

 piratory organs of the grasshopper agree mainly with the 

 general description of the organs of insects given in the 

 next section. 



Microscopic Objects. — These may be bought ready 

 mounted, or may be examined fresh. A portion of the 

 covering of the large eye may be cut off and the dark layer 

 on the inside of the covering scraped off to make it trans- 

 parent. What is the shape of the facets ? Can you make 

 any estimate of 

 their number? A 

 portion of the 

 transparent hind 

 wing may be used, 

 and the "veins" 

 in it studied. A 

 thin bit of an abdominal segment containing a spiracle 

 will show the structure of these important organs, 



Growth of the Grasshopper. — Some species hibernate in 

 sheltered places and lay eggs in the spring, but adult species 

 are scarce at that season. Most species lay the eggs in the 

 fall ; these withstand the cold and hatch out in the spring. 

 Those hatched from one set of eggs sometimes stay together 

 for a few days. They eat voraciously, and as they grow, the 

 soft skin becomes hardened by the deposit of horny sub- 

 stance called chitin.This retardsfurthergrowthuntil the in- 

 sect moults, the skin first splitting above the prothorax. Af- 

 ter hatching, there are five successive periods of growth . At 

 which moult do the very short wings first appear? (Fig. 115) 



Fig. 115. — Kr.n and Moults of a Grasshopper. 



