THE GRASSHOPPER 



II 



their possessors to grasp their food (a) ; and a number of kinds, 

 like the hind legs of the grasshopper (c) , are longer and stronger 

 than the others and especially adapted for leaping. 



Each leg is made flexible by a number of joints which divide 

 it into distinct segments. These segments have all been given 

 names which are important for two reasons : (i) they are often 

 descriptive of the part named, and (2) they enable us to talk 

 and write about the 

 various parts intelli- 

 gently. The segment 

 of the leg attached to 

 the body is called the 

 coxa; the next is the 

 trochanter; then fol- 

 lows the long slender 

 femur; then the tibia 

 with spines on its inner 

 surface; and finally the 

 tarsus. The tarsus 

 consists of three dis- 

 tinct segments, but the 

 one next to the tibia 

 really represents three 

 that are fused together. 

 If the undersurface of 

 this segment is ex- 

 amined, three pads 

 will be found, each belonging to one of the fused segments. There 

 are therefore five tarsal segments the usual number in all in- 

 sects. The final tarsal segment bears a pair of curved claws which 

 make it possible for the grasshopper to cling to rough objects, 

 whereas the pads on the underside of the tarsal segments enable 

 the animal to walk on smooth surfaces. The pad belonging to 

 the last tarsal segment lies beneath the claws. Of particu- 

 lar interest are the two hind legs of the grasshopper, since these 



FIG. 2. Legs of insects showing relation be- 

 tween structure and function. 



a, grasping leg of praying-mantis ; b, running 

 leg of a beetle ; c, leaping leg of a grasshopper : 

 d, digging leg of mole-cricket; e, swimming leg 

 of beetle. (After Sedgwick.) 



