344 



THE LOCUST 



General External Features: (The Carolina locust, Dissosteira 

 Carolina ; and the red-legged locust, Melanoplus f emur-rubrum) .— 



A division of the body into regions known as head, thorax, and 

 abdomen is apparent in the locust (Fig. 168) as in the crayfish; 

 although the number of somites in these regions cannot be exactly 

 compared in types of arthropods that are so widely separated as 



A 



B 



Fig. 168. — Representative locusts. 



A, the New Mexico long-winged locust, Dissosteira longipennis, adult female, enlarged 

 about one-third. B, southwestern lubber grasshopper, Brachystola magna, adult female, 

 natural size. (From Farmers' Bulletin No. 747, U. S. Dept. Agr.) 



insects and crustaceans. In hke manner, the metamerism is obvious 

 in the abdominal region of the locust, but obscure in the head and 

 thorax. Ten somites can be easily recognized in the abdomen, 

 and there are three thoracic somites, as indicated by the three 

 pairs of legs. The number of somites in the head is a vexed ques- 

 tion among students of insect anatomy. There is clear evidence 

 of four, since there are three pairs of mouth appendages and the 

 antennse, and there are probably not less than five somites in this 



