HEXAPODA. 



61 



tearing their prey ; others feed upon vegetable matter, and 

 have jaws for chewing this kind of food. Among the suck- 

 ing insects the butterfly merely sips the nectar from flowers, 

 while the mosquito needs a powerful instrument for piercing 

 its victim. In this place the typical form of the mouth- 

 parts as illustrated by the biting insects is described. The 

 various modifications of it presented by the sucking insects 

 are described later, in the discussion of the characters of 

 those insects. 



In the biting insects, the mouth-parts consist of an upper 

 lip, the labrum {Wbrum) (Fig. 75, 8); an under lip, the labium 

 (la'bi-um) (Fig. 75, 12); and two 

 pairs of jaws between them. These 

 jaws open sidewise, instead of in 

 a vertical direction, as do the 

 jaws of the higher animals. The 

 upper pair of jaws are called the 

 mandibles (man'di-bles) (Fig. 75, cli 

 10); the lower pair, the maxilla 

 (max-il'lae) (Fig. 75, 11). There 

 may be also within the mouth 

 one or two tongue-like organs, 

 the epipharynx (ep-i-phar'ynx) and 

 hypopharynx (hy - po - phar'ynx) 

 (Fig. 75, 13). The epipharynx is 



attached to the upper wall of the cavity of 

 the mouth, and the hypopharynx to the 

 lower. The position of the hypopharynx is 

 quite analogous, therefore, to that of our 

 tongue. 



The mandibles vary much in form, but 

 usually each consists of a single sclerite. 

 The maxillae of biting insects, on the other 



"Tig. 76.— Maxilla of a hand, are very complicated organs, each COm- 

 Tiger Beetle. , . , ... t^ u -n 



posed of several sclentes. .bach maxilla 

 bears an appendage consisting of several segments; these 



<r^ 



\>. 



Fig. 75. — Mouth-parts of the Red- 

 legged Locust. 



