60 



EXTERNAL ANATOMY. 



pulled outwards or forwards with a pair of forceps, it will 

 be seen that it is a thin parchment-like membrane, 

 with a stiff anterior edge, which is nearly straight, while 

 the rounded outer and posterior margins are thin and 

 flexible. When the wing is fully extended its upper surface 

 is convex, and its anterior margin is rendered still more 

 rigid by being overlapped b}^ the internal margin of the up- 

 per wing or wing-cover. The numerous radiating veins are 

 so arranged that their elasticity causes the wing to fold upon 

 itself like a fan as soon as its margin is released. 



The Legs (Fig. 35). The large leaping leg consists of 



five regions: The coxa{c), 

 or basal division, which is 

 joined to the thorax; a 

 small articulation, the tro- 

 chanter, (tr), immovably 

 joined to the distal dorsal 

 portion of the coxa; the 

 femur, (/), a long, swollen, 

 club-shaped segment, which 

 makes up nearly half the 

 lengthof the limb. When the 

 animal is at rest it extends 

 upwards and backwards, 

 with its distal end above the dorsal surface of the body. 

 This joint contains the powerful leaping muscles, the areas 

 indicating the points of attachment being visible ex- 

 externally. The tibia, {ti) is about as long as the femur, 

 but is very slender and of uniform diameter. When at rest 

 it extends downwards and backwards, at an acute angle, 

 from the distal end of the femur, but in the act of jumping 

 it is thrown backwards and the limb becomes straight. 

 Tiie tarsus (ta), or foot, is made up of four movable pieces. 

 The first and longest carries upon its lower surface three soft 

 pads {p), which by their adhesion to foreign bodies serve as 

 points of resistance in leaping. The second joint is much 



Fig. 35. — Hind leg of Melanopliis bivit- 

 tatus. Original. 



