The ventral sclerite is known as the sternum. The sterna 

 of the three thoracic segments are designated as the pro- 

 sternum, mesostemum, and metastermim respectively. 



The dorsal part of the body-wall of each segment is called 

 the tergum. This name is also applied to the dorsal part of 

 the three thoracic segments collectively. 



The tergum of the prothoraxis frequently called the prono- 

 tum ; the tergum of the mesothorax, the mesonotum ; and 

 that of the metathorax, the metanoturn. 



There are in this insect two pairs of thoracic spiracles. 



APPENDAGES OF THE THORAX. 



The appendages of the thorax are the legs and wings ; the 

 number and distribution of these have already been given. 



Legs. — Examine the ventral aspect of the first pair of 

 legs. Each leg will be found to consist of the following 

 named parts : — 



Coxa. — This is the proximal segment of the leg. It is 

 subglobular in outline. Examine the cephalic aspect of the 

 coxa, and note the longitudinal suture which traverses this 

 side of it ; this is shown better on the mesothoracic legs. 



Trochanter. — This is the second segment of the leg, and 

 is much smaller than the coxa. The ventral aspect of it is 

 much longer than the dorsal. 



Femur. — This is the third and principal segment of the 

 leg. 



Tibia. — This is the fourth segment of the leg. It nearly 

 equals the femur in length, but is more slender. 



Tarsus. — The tarsus includes all of that part of the leg 

 distad of the tibia. It consists in locusts of three segments. 



The last segment of the tarsus bears a pair of claws. 



On the ventral surface of the tarsus there is a series of 

 cushions ; these are called pulvilli. The distal segment of 

 the tarsus bears a single pul villus which projects between 



