428 BULLETIN 63, UNITED STATES NATIONAL MUSEUM. 



General ohservaiions. — The mentiim appears to be more trapezoido- 

 parabolic, otherwise as in giganiea. 



The prosterniim is also about the same as in that species, probably 

 not as prominent ventrally, and the ante-coxal portion more gradually 

 and evenly continuing the surface line; frequently more strongly 

 mucronate behind, the mucro maj'^ be conical and more or less de- 

 flexed, or vertically truncate behind with the angle mucroid and de- 

 flexed. In the series before me the prosternum is not even in one 

 instance horizontal between the coxa?, but ahvays more or less convex. 



The mesosternum is variable, at times quite flat to vertically arcu- 

 ate, broadly, and more or less strongly concave. 



The abdominal process is wider than long and about a fourth of 

 its own breadth wader than the metasternal salient. 



The post-coxal portion of the first abdominal segment is equal in 

 length to that of the second; the latter is about a fifth longer than 

 the third and almost twice as long as the fourth. 



The metasternum laterally between the coxte is about as long as 

 the width of a mesotibia at apex. 



The profemora are subclavate and not noticeably swollen, greatest 

 dorso- ventral diameter is at the junction of the middle and apical 

 thirds, the surface lines are feebly arcuate; tlie tibial grooves are 

 well developed, their margins converging and becoming contiguous 

 some distance from the base. 



In the series at hand all of the tibiic are more or less arcuate. The 

 protibise are slightly compressed, obsoletely carinate externally, and 

 the tarsal grooves are not evident. 



The mesofemora narrow but slightly toward base and not at all 

 swollen ; the grooves ai-e rather short, their rather coarse margins 

 converging and becoming contiguous near the middle, the floors are 

 slightly concave. 



The mesotibife are quite cylindrical in section; their tarsal grooves 

 are more or less evident as glabrous, opaque grooves limited by 

 asperities. 



The metafemora are almost subequal in width throughout, the 

 grooves are rather short, the margins converging to become almost 

 evanescent before uniting at the distal side of the middle. 



The metatibise are subcylindrical in section, slightly flattened ex- 

 ternally and asperate. 



The articular cavities are quite closed. 



The tarsi are variable in thickness, usually moderately long and 

 somewhat stout. Tn one specimen collected at Tucson, Arizona, the 

 tarsi are distinctly slend(M'. 



The ])rotarsi are about a fourth of their length shorter than a 

 mesotarsus. eloints 2—1. inclusive. siibe(|ual in length and very 



