DoEHiNt;: Lki'Ykoxia QrAi)HA.\(irLAKis. 549 



cpistcrnum. more irrciiuhu' in shape and extends dorsad into a 

 tajiei'ing point. The episternuni is connected to the sternum by a 

 naiTow prcco.ralr bridge (pL LVII, fig. 4), called the precoxale by 

 Taylor (IDlSi. It is fused to the ventroentad surface of the epi- 

 sternuni and it is not distinctly separated from the sternum. The 

 epimeron is connected in much the same manner by a postcoxale 

 bridge (pi. LVII, fig. 4) which, however, runs to the laterodorsal 

 angle of the epimeron instead of the ventral. 



The sternum (pi. LVII, figs. 4 and 5) of the prothorax is small 

 and about equal in length and width. It consists of a single sclerite, 

 which is folded and curved in such a manner that it is difficult to 

 describe its exact shape. 



The anterior margin of the sternum is bent back against the 

 caudal surface of the sclerite (pi. LVII, fig. 4), so that in an un- 

 cleared specimen it appears as a chitinous ridge or distinct sclerite. 

 In the drawing of the cephalic aspect this has been straightened out 

 into a natural position. The lateral margins of the sternum (pi. 

 LMI, fig. 5l curve cephalad, thus forming a semicylindrical cavity 

 into which the membrane connecting the labium with the sternum is 

 fastened. During the process of sucking the sap the labium is 

 probably drawn up into this trough in order to not interfere with 

 the action of the stylets. The anterolateral angles of the sternum 

 bear the furca (Taylor, 1918), which are the processes for the at- 

 tachment of muscles. 



The trochantin (pi. LVII, fig. 5) is a small but very distinct knob- 

 like sclerite just below the ventral end of the episternum. 



THE MESOTHOR.\X. 



The mesothorax (pi. LVII, figs. 7 and 8) is closely connected with 

 the metathorax, the latter being partially covered both on its dorsal 

 and ventral surfaces by overlapping parts of the mesothorax. The 

 mesothorax, likewise, is covered by the pronotum with the exception 

 of the scutellum, the anterior margin of which follows the deeply 

 incised posterior margin of the pronotum. The membranous ster- 

 nellum of the mesothorax is fused with the presternum of the 

 metathorax so that it is difficult to differentiate the two. 



The mesonotum (pi. LVII, fig. 7) is divided into four distinct 

 areas or sclerites. The first of these is the prescutum, which occu- 

 pies the anteromesal portion and is bounded laterad by two longi- 

 tudinal sutures which curve mesad for a short distance, thus 

 indicating the caudal boundary of the sclerite. The prescutum 

 is heavily chitinized in spite of the fact that it is entirely covered 



