OF WASHINGTON, VOLUME XVIII, 1916 139 



ventral point is at the beginning of the eusterno-sternellar line 

 and is defined by muscle sc-cx-st, to the scutal line, homologous 

 to muscle tp-st of the abdomen. The anterior is defined by muscles 

 p-cx, described before. From this lobe considered to be the coxa 

 projects the trochanter which is moved by a muscle (sp-i) at- 

 tached to its lower surface and to sternopleural suture. Thus 

 that region in the abdomen called the coxal lobe can be sho \vn 

 to have developed the leg in the thorax. The eusterno-sternellar 

 line extending between the coxa divides the eusternum (ESt) 

 from the sternellum (Stl). Muscles (e-s-i) run anteriorly and 

 posteriorly from it to the respective inferior cunea. The poste- 

 rior of these may be considered as abdominal muscles pn-st and 

 e-s-i. It will be seen that the abdominal muscles i-est and /-*// 

 of the abdomen are retained in the thorax. 



In the Lepturinae it was stated, in discussing the abdomen 

 that the coxal lobe was large and the postcoxal area relatively 

 much smaller. In the thoracic segments the coxa is also corre- 

 spondingly large so that in the prothorax they meet medianly. 

 Also the postcoxal area is practically divided into an anterior 

 and posterior half. In the Cerambycinae these coxae are still 

 smaller, and the legs are often absent, corresponding to an indis- 

 tinguishable abdominal coxal lobe. Parenthetically it might 

 be remarked that the adults of Prioninae and Lepturinae are 

 characterized by large conical coxae. 



Again comparing the Cerambycinae it will be seen that the 

 pleural suture of meso and metathorax does not extend forward 

 to the inferior cunea but anteriorly the pleurum and presternum 

 are fused. This corresponds to a similar modification in the 

 prothorax where the pleural zone, presternum and eusternum are 

 all fused, and the postcoxal area has been crowded back with 

 the sternellum. 



In the prothorax a lengthening of all the anterior regions has 

 taken place to accommodate the attachments of the many muscles 

 for moving the head. These muscles are not drawn but their 

 prothoracic attachments are represented by dots in the figure. 

 They occupy practically all the space not utilized by other 

 muscles. These are all attached to the collar and none to the 

 head proper except the inferior and superior retractor muscles. 

 Likewise for mechanical reasons a solidification and chitiniza- 

 tion of many of the areas has taken place. All the notal sub- 

 divisions above the alar ;in>;i have been fused into the larue 

 rectangular pronotum (PN). In the Lepturinae this fusion often 

 includes the alar area and is then spoken of as the protergum 

 (PrTg). Beneath the pronotum, in turn, lies the alara area, 

 the pleurum and epicoxal and precoxal areas surrounding the 

 coxa. The muscles between these ,-ireas can readilv be homolo- 



