160 



LOCUSTS, BUTTERFLIES, BEES, WASPS 



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

 it can move from i)laco 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 crawhng, although 

 the first four are used mainl}' 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 wliile 

 crawling. 



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

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



Mouth 



Caeca 



^!I^ Urinari/ tubes 

 Intestine 



^qlamS' Ihnradr fiancjlia Abdominal ganglia 



Fig. 90. — Internal structure of a grasshopper. 



teriorly and quickly widens into the crop. The salivary 

 glands lie beneath the crop and connect with the mouth 

 thi'ough a long, slender tube. The stomach succeeds the 

 crop and lies in the al)ilomen. Six pairs of long, tapering 

 |)0uches, the (jastri circii (Fig. 99), surround the anterior 

 end of the stomacli. The,y secrete a digestive juice and 

 discharge it into tlit^ latter organ. A circk^ of several slentler 

 tubes, the vrlnari/ liihcs, nn^e from the anteiior end of the 

 intestine. They uidicate where the stomacli ends and the 



