INSECTS. 103 



The thorax, fonned by the union of three segments 

 of the skeleton, supports six jointed legs, and gene- 

 rally fou7\ sometimes two icings. These last, liow- 

 ever, are frequently wanting. 



The abdomen is destitute of legs, and -contains the 

 viscera, connected with nutrition and reproduction. 



The legs of insects, as above stated, are invariably 

 six in number, one pair being attached to each of 

 the segments of the thorax. Considered separately. 



Fig. 68.— hind leg of bee. 



each of these legs is made up of several pieces, Avhich 

 well deserve our notice. The first division of the 

 leg, or tliat in immediate connection with the thorax, 

 is called the liip {coxa), and upon this, as upon a 

 centre, the movements of the limbs are performed. 

 To the extremity of the coxa, a small moveable piece is 

 attached, called the troclianter, to which succeeds the 

 thigh (femur), which is tlie thickest and most robust 

 of all the divisions of the limb. Tlie next piece, 

 called the shank (tihia), is occasionally of considerable 

 length, and is connected with the last by a hinge. 

 To its extremity is appended the foot {tarsus), com- 

 posed of a consecutive series of small segments, 

 varying in number from five to one, the last of which 

 is armed with claws, or other appendages, adapted to 

 different kinds of progression. With these divisions 

 of tlie leg, it is necessary that the student should be 



