WHAT AN INSECT IS LIKE: OUTSIDE 



7 



Between lacinia and palpus is a middle appendage (the 

 galea) that is a curved and more or less spoon-shaped plate, 

 whose function seems to be that of closing the mouth later- 

 ally for the retention of food. 



c 



Mandible 



Ventral aspect of labium 



B - 



Dorsal side of maxilla 



Fig. 3. — The mouthparts of stonefly nymph. Figures A and B represent the head divided hori- 

 zontally through the esophagus e, and both halves exposed from within: /, labrum or upper lip: 

 tn, mandibles; mx, maxillae; Ir, labium or lower lip; h, hypopharynx, or tongue. Figures C, D, and 

 E represent these parts, detached. 



The thorax is composed of tnree segments, each of which 

 bears a pair of legs. Insects proper are called Hexapods 





