1918] Thoracic Sclerites of Hemiptera 229 



Sternum. Figures 2 and 3. The sternum (st) of the pro- 

 thorax is narrow from front to rear and apparently consists of 

 but one sclerite, which bears the furca, an interior projecting 

 fork for muscle attachment. The coxa is divided into a front 

 portion, the veracoxa (vex), and a rear portion, the meron (me). 



Mesothorax. Figures 1, 2 and 4. 



The mesothorax is by far the largest and most typical 

 segment. 



Notum. Figures 1 and 4. The mesonotum, as in most 

 insects, is divided primarily into two distinct plates. The first, 

 which is that part of the notum visible externally, is roughly 

 pentagonal in shape and is called the scuto-scutellum by 

 Crampton, 1914A, 1914B. This portion has often been called 

 notum, but this term should be applied only to the whole dorsal 

 region of the segment. The second primary division of the 

 notum is the postscutellum, which is concealed behind and 

 somewhat beneath the scuto-scutellum, and hence is not shown 

 in the figures. 



The scuto-scutellum is in turn subdivided by various infold- 

 ings of chitin into several parts. The foremost of these is the 

 anterior phragma (aph), which projects under the pronotum 

 and is connected with it by membrane. Immediately behind 

 this is the pretergite (prt), which is narrow and is fused with 

 the rather large, bilobed prealare (pra) on either side. The 

 latter, as is usual in the Hemiptera, connects the notum with 

 the pleuron, anterior to the wing. Two distinct, nearly longi- 

 tudinal sutures, which approach each other posterior to the 

 middle of the tergum, mark ofif the prescutum (psc). The 

 scutum (sc) is an ill-defined region just posterior to the pre- 

 scutum, extending downward on either side and forming the 

 major part of the whole scuto-scutellum. Where the scutum 

 articulates with the wing base a small piece, the suralare or 

 supralare (sr), is partly marked off by a cleft extending forward. 

 (In some insects this piece is entirely separated from the 

 scutum by a suture.) Another cleft extending backward partly 

 defines a similar piece. These two pieces articulate with a free 

 plate, the notopterale (npt), which forms one of the principal 

 connections with the wing. The tegula (tg) in the Cicada is 

 poorly chitinized, but its homologue is clearly seen in the mem- 

 brane anterior to the base of the fore wing (Figure 1). A 

 broken suture nearly parallel with the posterior margin of the 



