Nov., 1902.] Passalus Cornutus. 305 



arc completely fused in the pro-thorax. This fused sclerite bet^ins 

 at the \*-shaped suture mentioned as forming the lateral boundary 

 of the anterior portion of the prosternum anci extends around the 

 coxal cavity and forms a suture with the posterior portion of the 

 sternum. The region in front of the coxal cavity probably corre- 

 sponds to episternum (2) ; that behind the coxal cavity to the epi- 

 meron (3). and that lateral to the coxal cavity and fused with the 

 pro-notum to the epipleuron. Its anterior and posterior boundar- 

 ies are free : its lateral fused with the pro-notum and its median 

 forms the lateral and posterior wall of the coxal cavity and unites 

 by a suture with the anterior and posterior portions of the sternum. 

 The fused condition of these parts is probably related to the bur- 

 rowing habit of the beetle, the solid piece giving greater strength 

 both in forming an attachment for muscles and articulations for 

 the fore-legs. 



The pro-thoracic leg consists of the usual number of seg- 

 ments. They are named as follows, beginning at the body or 

 proximal end : coxa, trochanter, femur, tibia, and tarsus. The 

 coxa ( 8 ) is the very large sclerite placed transversely in the coxal 

 cavity and reaching three- fourths of the distance from the median 

 line to the lateral border of the pro-thorax. It can be rotated for- 

 ward and backward on its long axis. It is articulated on the 

 median extremity with the large femur ( 10) and the small tro- 

 chanter ( 9 ) l)ing on its anterior proximal surface. The coxa. 

 sends a small projection between these parts on the ventral surface 

 resembling a ball-and-socket joint, and on the dorsal surface sends 

 forward a broad flat piece. Between these ventral and dorsal 

 pieces the femur and its fused trochanter articulate. 



The trochanter (9) is a small segment lying on the anterior 

 surface of the proximal end of the femur. It is about one-fourth 

 the length of the femur. 



The femur (10) is the largest segment of the leg and is flat- 

 tened dorso-ventrally. On the anterior border of the distal por- 

 tion there is a cavity into which the tibial spur fits when the tibia 

 is flexed. The dorsal surface of the dorsal wall of this depression 

 bears a bundle of bristles in a slight depression just back of the 

 distal extremity. This distal wall of the depression serves as a 

 brace against which the tibial spine works. The tibia (11) is 

 nearly as long as the femur and is flattened also dorso-ventrally. 

 On its posterior border it bears eight blunt spines, and on its 

 anterior border a single articulated spine near the distal end called 

 the tibial spine. There is a circlet of bristles around the base of 

 the spine. 



The tarsus (12) consists of five segments of which the first 

 and third are the longest ; the remaining three small and similar 

 in shape ; the fifth bears a pair of claws, two short bristles are 



