Nov., 1902.] 
Passalus Cornutus. 
3°3 
are completely fused in the pro-thorax. This fused sclerite begins 
at the V-shaped suture mentioned as forming the lateral boundary 
of the anterior portion of the prosternum and 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) lying 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 ( 1 1 ) 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 
