ANIMALS WITH JOINTED FEET^THE ARTHROPODS 



223 



Fig. 11-19. The lubber grasshopper (Romelea micropfera), common in our Southern states, demonstrates insect parts 

 clearly and with a minimum number of modifications. It is commonly used in zoology classes. This is a male. 



invertebrate world. The grasshopper is se- 

 lected because of its relatively large size 

 and because it is well known to everyone. 

 Furthermore, it shows certain primitive in- 

 sect characteristics that make it easier to 

 understand than other members of the 

 group. Its many species are world-wide in 

 distribution, living in and feeding on grass 

 or any other available leafy vegetation. It 

 sometimes increases in such numbers that 

 it becomes a serious pest, great hordes de- 

 vouring almost everything of plant origin, 

 except wood, that lies in its path. Grass- 

 hoppers have been known to stop trains 

 from climbing grades because their crushed 

 bodies caused the wheels to slip on the rails, 

 and to cause cars to skid on the roads at 

 places where the insects cross, as their 

 bodies are crushed beneath the tires. Corn 



fields through which they pass are sheared 

 to the ground and left in desolation. 



Structure. Externally, like all insects, the 

 grasshopper is divided into three parts, the 

 movable head, the thorax, and the abdo- 

 men (Figs. 11-18, 11-19). There is a con- 

 siderable amount of fusion of segments 

 when compared to the crayfish. For exam- 

 ple, the head appears as a single structure, 

 but it is made up of six segments. Likewise, 

 the thorax is composed of three segments, 

 and there is a variable number of segments 

 in the abdominal region, usually eleven. A 

 pair of legs is attached to each of the three 

 thoracic segments, and a pair of wings to 

 each of the last two. The legs have several 

 parts which named from the body outward 

 are the coxa, trochanter, femur, tibia, and 

 tarsus. The hind legs are long and well 



