22 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 94 



erally known as the scutellum. It is formed by the union of the three 

 normal sclerites of the mesonotum, the prescutum, scutum, and 

 scutellum. 



The posterior triangular portion is the scutellum (figs. 4 C, 3 A, 

 4 A, scl), which overlaps the metatergum posteriorly and is separated 

 in front from the prescutum by an obvious transverse suture. Its 

 surface is rather densely setigerous, with a narrow impunctate anterior 

 margin. A rectangular area (sclp) on the ental surface of the posterior 

 part of the scutellum is the part that is in close contact with the an- 

 terior edge of the metanotum. The anterior margins of the area are 

 continued forward as the axillary cords of the wings (axe) which 

 appear to proceed from the sides of the prescutum. 



The part of the shield anterior to the scutellum is the prescutum 

 (figs. 4 C, 3 A, 4 A, psc). It overlaps the scutellum somewhat posteri- 

 orly, especially at the sides. The prescutum is short and transverse, 

 bearing the anterior notal wing process (anp), the lateral emargination 

 (em), and a second process posterior to this. An irregular transverse 

 line extends between the anterior wing processes dividing the pre- 

 scutum into two areas. The posterior of these bears numerous setae, 

 somewhat smaller than those of the scutellum, on its caudal half, 

 and also a very few exceedingly fine setae at the anterior angles near 

 the wing processes. The anterior area bears a small group of six 

 to eight setae on each side of the center on the caudal margin, 

 and also a median pair of very large setae (fig. 4 C). 



The scutum (fig. 4 A, set) of the mesothorax is completely sepa- 

 rated by the union of the scutellum and the prescutum along the line 

 of the suture pss into two parts. It projects laterad from beneath 

 the shield and forms the posterior notal wing processes. Its exact 

 outline is obscure as it is more or less united to the other sclerites 

 entad. The axillary cord (axe) appears to arise from the scutum but 

 probably merely traverses it from the margin of the scutellum of 

 which it is the continuation. The ectal surface on each side is ap- 

 parently transversely traversed by a fine suture (sets) which marks 

 an ental apodeme. 



The sternum of the mesothorax is represented chiefly by a single 

 large sclerite (s. II) on the median part of the ventral aspect. It is 

 separated from the anterior margin by a narrow strip, the prepectus 

 (prp), which extends from the anterior portion of one episternum 

 along the margin in front of the sternum and onto the other epi- 

 sternum. The prepectus may not be a distinct sclerite, but it is sepa- 

 rated from both the sternum and the episternum by a distinct line 

 or ridge and is somewhat inflexed. It appears to be divided into three 



