58 STUDIES OF ANIMAL LH'K. 



Why could not the third pair extend in the same 

 direction as the other two pairs ? 



d. Observe these principal segments in the leg, — 



(1) the Femur, the swollen more proximal 



segment ; 



(2) the Tibia, the slender middle segment ; 



(3) the Tarsus, the foot. 



e. Observe the joints of the tarsus. 



(1) Of what advantage are they ? 



(2) W^at are the hooks and pads for '? 

 3. The Wings. 



a. What is the resting position of the wings ? 



b. How are they related to each other with regard 



to their position while at rest ? How are they 

 related when outspread ? 

 The straight ridge-like arrangement of the wings 

 when at rest gives the name Orthoptera 

 (straight-wings) to the order of insects to 

 which the grasshopper belongs. 



c. Compare the fore- and hind-wings with respect to, — 



(1) their shape ; 



(2) their size ; 



(3) their thickness ; 



(4) their folding. 



d. The Veins, thread-like thickenings of the wings. 



(1) What is their arrangement? 



(2) In which part of the wings are they 

 strongest ? Why ? 



Why are the wings attached so near to the dorsal 



edge of the body ? 

 Do the fore- and hind- wings differ in function? 



Give reason for your answer. 

 Why is the thorax the strongest part of the body ? 



