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TEXTBOOK OF ZOOLOGY 



the segments of the thorax is called the tergum, the ventral or under 

 surface, the sternum, and each side, the pleurum. The legs are made 

 up of five main segments: the coxa, trochanter, femur, tibia, and 

 tarsus. The coxa forms the joint by means of which the leg is at- 

 tached to the body. The trochanter is small, while the femur, or 

 thigh, and tibia are large, forming the greater part of the leg. The 

 tarsus or foot is composed of five smaller segments and a pair of 

 claws. In insects the tarsal segments may differ in size, length, 



Fig. 175. — Jumping leg or third thoracic appendage of Rhomaelia microptera. 

 C, coxa; F, femur; P, pulvilli ; Ta, tarsus; Ti, tibia; Tr, trochanter. (From White, 

 General Biology.) 



shape, and number, and are useful in classification. The legs are 

 greatly modified for obtaining food, running, walking about, swim- 

 ming, and jumping. They are also modified for the production or 

 reception of sound, for the collection of food, such as pollen, and for 

 copulation. In some species they also exhibit secondary sexual char- 

 acters. 



The wings are thin folds of the skin, shaped and strengthened with 

 veins in various ways. The presence of wings is one of the most 



