It is believed that the dorsal part of each thoracic segment 

 consists typically of four sclerites. These are named, be- 

 ginning with the cephalic, praescutum, scutum, scutellum, 

 and postscutellum. These sclerites may be distinguished in 

 the dorsal parts of the mesothorax and metathorax {ntesono- 

 tum and metanotum) of many insects ; but the pronotum 

 consists usually of a single piece. In the insect which we 

 are studying, although the pronotum consists of a single 

 piece, it is crossed by three well marked sutures, indicating 

 the division into four sclerites, which may be named as in- 

 dicated above. 



On the latero-dorsal aspect of the pronotum the suture 

 between the praescutum and the scutum extends cephalad 

 for a short distance and is then interrupted ; the lateral por- 

 tions of this suture is parallel with and quite near to the 

 cephalic margin of the pronotum. Near the center of each 

 lateral aspect of the pronotum there is a short cephalo-caudo- 

 dorsal suture which separates the lateral fourth of the scutel- 

 lum from the mesal part of that sclerite. None of the 

 sutures extend to the lateral margin of the pronotum. 



Make a drawing of the lateral aspect of the pronotum. 



Ventral Part (Prosternum). — On the ventral surface of 



this segment between the legs there is a sclerite which bears 



a large tubercle ; this is the sternum of the prothorax or 



i 

 prosternum. 



Lateral Parts. — Owing to the great development of the 

 pronotum, which covers the larger portion of the sides as 

 well as the dorsal surface of the prothorax, the lateral parts 

 of this segment are rudimentary. The following named 

 sclerites, however, may be distinguished. 



Episternum. — Between the pronotum and the end of the 

 lateral prolongation of the prosternum, which extends on 

 each side of the segment cephalad of the leg, is a conspicu- 

 ous triangular sclerite ; this is the episternum. 



