90 



ANATOMY OF AN ARTHEOPOD. 



32 A, c), a broad plate, which is followed by a smaller plate united 

 to the front of the clypeus, called the labrum or "upper lip" 

 (L). The plate on each side below and behind the eyes is called 

 the gena or cheek ((?). Ocelli are absent in this type, other- 

 wise they would be situated on the epicranium. The thorax 



Fig. 31. — Structuric of an Akthropod (Periplancta ajnericana). 



B, head; Th, thorax; Ah, abdomen; Mxp, maxillary palps; Lp, labial palps; JIf, 

 maxiUee ; Ant, antennae ; E, eyes ; Ep, epicranium ; /, fenestra ; P, prothorax ; U, 

 mesothorax ; Me, metathorax; Ce, cerci ; S, styles: Mw and Mew, meso- and meta- 

 thoracic wings ; PI, M.l, and Me.I, legs ; Fe, femur ; Ti, tibia ; Tr, tarsus ; 1-10, abdom- 

 inal segments. 



is composed of three segments, united by sutures. Each seg- 

 ment is known respectively as the pro-, meso-, and metathorax 

 (fig. 31, Th). The tergum or pronotum, the upper portion, is 

 prolonged over the neck. The mesothorax, which is smaller 

 than the prothorax, bears a pair of leathery wings. These 



