﻿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 modifications of the 

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

 mandibles are lengthened out into a piercing-like sting, while 

 some of the other parts are reduced in size, or become al- 

 most obsolete. In another group the maxillae are greatly 

 elongated, with their edges joined to form a tube, while the 

 other parts of the mouth are scarcely to be discerned. In 

 another group the labium is greatly lengthened to form a 

 tongue-like organ for lapping up 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 verv 

 soft. 



If the pupils w^ill 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 transparent, 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 



