160 



LOCUSTS, BUTTERFLIES, BEES, WASPS 



Locomotion of the locust. — It has three ways by which 

 it can move from place to place. First, it has the two pairs 

 of strong wings suitable for rapid and extended flight. 

 Second, it has six well-developed legs for crawling, although 

 the first four are used mainly in this method of locomotion 

 for the hind ones seem unwieldy and ill adapted to this 

 slow kind of progress. Lastly, it uses the large and muscu- 

 lar hind legs for jumping. In comparison with its size, 

 the locust possesses extraordinary leaping power. More- 

 over, each of the six legs ends with two hooked claws which 

 enable the locust to retain its hold upon objects while 

 crawling. 



The digestive system and food of the locust. — The guHet 

 leads upward (Fig. 99) from the mouth, then turns pos- 



Caeca 



Urinary tubes 

 •sttne 



qlmids Thoracic ganglia Abdominal ganglia 



Fig. 99. — Internal structure of a grasshopper. 



teriorly and quickly widens into the crop. The salivary- 

 glands lie beneath the crop and connect with the mouth 

 through a long, slender tube. The stomach succeeds the 

 crop and hes in the abdomen. Six pairs of long, tapering 

 pouches, the gastri cceca (Fig. 99), surround the anterior 

 end of the stomach. They secrete a digestive juice and 

 discharge it into the latter organ. A circle of several slender 

 tubes, the urinary tubes, arise from the anterior end of the 

 intestine. They indicate where the stomach ends and the 



