PARTS OF AN INSECT. 67 



palpi ; and a lower lip, called the labium, which represents 

 still another pair of jaws joined together; to this joined 

 piece, or labium, are attached a pair of jointed feelers, called 

 labial palpi. In Fig. 68 these parts are shown separated 

 from the head. 



The numberless varieties of mouth-parts, peculiar to dif- 

 ferent insects, are in reality made up by modiiications of the 

 parts above described. Thus, in one group of insects, the 

 mandibles may be lengthened out into a piercing-like sting, 

 while some of the other parts may be reduced in size, or be- 

 come almost obsolete. In another group the maxillte may be 

 greatly elongated, with their edges joined to form a tube, 

 while the other parts of the mouth are scarcely to be dis- 

 cerned. In another group the labium may be gi'eatly length- 

 ened to form a tongue-like organ for lapping iip food, while 

 the mandibles — so big and hard in some insects — are barely 

 perceptible, and of no use to the insect. 



Not only, then, do these parts assume different propor- 

 tions and different shapes in the different groups of insects, 

 but they also vary greatly in being very hard or very 

 soft. 



If the pupils will examine the different kinds of insects' 

 wings, taking the front-pair of wings for example, they will 

 find a marked difference between them, some being very 

 large and transparant, as in the dragon-fly, others being hard 

 and opaque, as in the front wings or elytra of a beetle. 

 Compare the broad and brilliant-colored wing of the butter- 

 fly with the straight and narrow fore-wing of a common 



