— 5i — 



Make a drawing of the ventral (outer) aspect of the 

 labium. 



PARTS OP THE THORAX. 



PROTHORAX. 



Dorsal aspect. — The pronotum is not divided into differ- 

 ent sclerites, but appears as a single, firm convex plate, bear- 

 ing a median impressed line, and, laterad of this line, on 

 each side near the caudal margin, a short, linear depression. 

 At the acute lateral margins, the pronotum is inflexed, ex- 

 tending a little distance ventro-mesad on the ventral 

 (pleurals, sir.) aspeqt of the body. This inflexed portion 

 is often called the prothoracic epipleura. 



Ventral aspect. — The sternum and the true pleural 

 sclerites or ' ' side pieces, ' ' together form the ventral aspect 

 of the prothorax. 



Sternum. — The sternum, constituting the median region 

 of this aspect, is irregularly-saddle-shaped, with a caudad- 

 projecting tongue between the coxal cavities. This tongue 

 after reaching the caudal margins of the coxae bends at right 

 angles and projects dorsad, the end expanding slightly into 

 two, dorso-laterad projecting points, which meet a ventro- 

 mesad proj ectingpoint of the epimeron on each side, and thus 

 form part of the enclosing, caudal boundaries of the coxal, 

 cavities. * 



Episternum. — The episternum, a large rhomboidal scler- 

 ite, constitutes most of the body wall between the sternum 

 and the epipleurae. 



Epimeron. — Separated from the caudal extremity of the 

 episternum by a distinct suture, is the narrow, curving 

 epimeron, whose expanded mesal extremity presents two, 

 pointed, curving processes, which enclose the coxal cavity 

 laterad and caudad. The meeting of the epimeron and 

 sternum caudad of the coxal cavity technically closes it, or 



