98 COMPARISONS OF STRUCTURE IN ANBJALS. 



folded up, when at rest, under wing-cases of 

 a more or less rigid consistence. The ordinary- 

 limbs are six in number, each divided into 

 five parts, of ■which the last, or foot, neA-^er 

 consists of more than five joints. These parts 

 are the hip, the trochanter, the thigh, the 

 shank, and the foot, or tarsus. 



Greatly are these Hmbs modified in detail in 

 various insects. Some, elevated on long, slender, 

 tremulous limbs, walk over and amidst the 

 blades of grass as if elevated on stilts. Others 

 have them expressly adapted for taking long 

 leaps, as the grass-hoppers, crickets, and tree- 

 hoppers : in some insects, as the fly, they 

 are provided with suckers ; in others they ter- 

 minate in two hooked, claws. Other insects 

 again, of aquatic habits, have the hind limbs 

 modified into paddles ; many have the limbs 

 adapted for climbing and clinging; many for 

 running with great rapidity; some for a slow 

 and heavy mode of progress, as the door-beetle ; 

 and ^ome again for buiTOwing like the mole, 

 as the mole-cricket, which well merits its 

 appellation. Thus, then, differently as insects 

 are organized from vertebrate animals, with re- 

 spect to the general framework of their bodies, 

 and the number position,' and conformation 



