THE EXTERNAL ANATOMY OF THE LOCUST 281 



a. The coxa. This is the first segment, and is attached to the 

 thorax by a tough, elastic membrane. It is short, almost globular, 

 and is more distinct on the prothoracic legs than on the other two. 



b. The trocJiautcr. This is the second segment, and is consid- 

 erably shorter than the coxa, and partially or entirely fused with the 

 next segment. It is hard to distinguish except in the first pair 

 of legs. 



c. The femur. This is the third and largest segment of the leg, 

 and in the case of the metathoracic leg contains the muscles used 

 in jumping. 



d. TJic tibia. This is the fourth segment, and is much more 

 slender than the femur, although about equaling it in length. 



e. The tarsus. This is the last division, and is made up of three 

 short segments freely articulating with each other. These seg- 

 ments bear a series of pads, which terminate on the last one in a 

 large, suckerlike disk known as the pulvillus. On each side of the 

 pulvillus is a pair of claws, the ungues. 



Exercise 7. Make drawings of the first and third thoracic legs, showing all 

 the parts. 



2. Wing-covers. The wing-covers are leather}' in texture and 

 do not fold fanlike over the abdomen, as do the two wings. They 

 are strengthened by numerous veins and cross veins. 



Exercise 8. Make an enlarged drawing of a wing-cover, noting the arrange- 

 ment and number of the veins and cross veins ; also note the attachment to 

 the mesothorax. 



3. Wings. These are sometimes called the second, or meta- 

 thoracic, wings. They are membranous in texture and fold fanlike 

 when not in use. They are also strengthened by numerous veins 

 and cross veins, as are the wing-covers. 



Exercise 9. Make an enlarged drawing of a wing, showing the arrangement 

 of the veins, method of folding, attachment, etc. 



