FORM AND FUNCTION 



263 



Make a drawing of the ventral aspect of the meso- 

 thorax. 



Dorsal View. -Lying- between the mesothoracic wings 

 is a quadrangular piece, with a raised shield-shaped 

 center. This is the mesonotnni. (Fig. 202, (7.) Typ- 

 ically speaking, the notum of each division of the thorax 

 should be composed of four sclerites, bearing the same 

 names as those already given the pronotnm. In this 

 case we cannot locate them, since the sutures are not 

 clearly marked. The first segment, the prsescutum, is 

 a very narrow plate, a mere line, not easily made out. 



Metathorax. 



Dorsal View. The shape and divisions of the meta- 

 thorax are similar to those of the mesothorax. As in 

 the mesothorax, the sutures cannot be satisfactorily 

 defined. 



Lateral View. - The lateral aspect of the metathorax 

 shows it to be composed of two sclerites, the episternum 

 and the epimeron. 



Episternum. - This sclerite extends from the front 

 half of the hind coxa to the base of the hind wing. 

 (Fig. 109, b.) 



Epimeron. Immediately joining the caudal margins 

 of the episternum is the epimeron, which likewise ex- 

 tends from the leg socket to the base of the wing. Add 

 a drawing of this lateral view of the metathorax to the 

 lateral view of the mesothorax already drawn. 



Ventral View. On the ventral part of the metathorax 

 there is but one sclerite, the metasternum. 



The Metasternum. Lying immediately caudad of the 

 mesosternum there is a large sclerite, the central part 



