Q U.S. NATIONAL MUSEUM BULLETIN 290 



epipleuron is present at the basal half of the elytra. The humerus is 

 quite evident in nearly all species, and there is a tendency in some 

 toward convexity of the elytral intervals, usually most evident at the 

 side of the elytra. 



Thoracic sternites: In all species, the anterior margin of the 

 prosternum lateral to each coxa is straight from a side view and 

 evenly rounded from an anterior view. The anterior margin of the 

 prosternum between the coxae is usually produced into a lobe or spine 

 but is unmodified in some. A lobe, when present, generally points 

 anteriorly, or diagonally downward; spines generally point downward. 

 The median portion of the prosternum is flat, slightly concave, or 

 even convex. The posterior margin on each side behind the coxae is 

 broadly emarginate, and each side is produced posteriorly into a more 

 or less distinct, stout, pointed lobe. The coxae are inserted at about 

 the middle of the prosternum and are separated by about their diam- 

 eter or a little less. The mesosternum is quite short and partially 

 overlaid by the prosternal processes ; the visible portion is often nearly 

 quadrate. The metasternum is distinctly wider than long and bears a 

 longitudinal, median groove or depression. The metasternum is 

 narrowest between the insertions of the second and third pair of legs 

 and broadest at its side. The metepisternum is triangular and broadest 

 anteriorly; it is generally rather coarsely sculptured and more pu- 

 bescent than the rest of the ventral surface. The metepimeron is much 

 reduced. 



Abdomen: The abdomen consists of five dissimilar segments; all 

 sutures except the fourth (usually), are distinct and straight. The 

 first segment is the largest and at its center is usually nearly as long 

 as the others combined. The second and third segments are subequal 

 and shorter than the others; they are nearly parallel side to side or 

 are wider laterally. The suture of the fourth segment lies at an angle 

 to the others, and the segment is visible as a narrow triangle on each 

 side or is narrowly visible at the middle and more broadly so on each 

 side. The fifth segment is about half the length of the first, and the 

 apical margin is broadly arcuate. At its center, the fifth segment bears 

 a more or less broad deep pit (female) or is simple (male). The 

 pygidium is quite large in all species; it is usually coarsely punctate 

 and in some is more or less distinctly, longitudinally carinate at the 

 center. 



Legs : The first and second pairs of coxae are more or less globular, 

 and the third pair is transversely oval. The trochanters are interstitial 

 and somewhat triangular; the femora are stout and broadest at about 

 their middle. The tibiae are a little longer than the femora, are broadest 

 apically, and lack spines. Each tarsus is about two-thirds the length 

 of a tibia, and its first thi-ee segments bear dense pads of pubescence 



