6 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 76 



On the side of the pronotum (fig. 1, s pr). which lies in a nearly 

 vertical plane, the most valuable character in both sexes is the 

 groove which crosses the center of the region from a point near the 

 <erminus of the transverse carina to the alar angle. This groove may 

 be entirely absent or it may be present, complete, or only partially 

 developed, straight or broadly curved, deep or shallow, broad or 

 narrow, uninterrupted or crossed at frequent intervals by diagonal 

 rugae. The groove is described as viewed from a position perpen- 

 dicular to the surface upon which it occurs and not from in front, 

 Punc^tures on the side are also valuable characters though not often 

 found. 



The scutum of the female usually has lateral notauli and a separate 

 crescent-shaped antero-medial groove (pi. 1, fig. 6). In some species 

 the notauli and the antero-medial groove are connected at the 

 antero-lateral corner, and are then termed continuous (pi. 1, fig. 5). 



The punctures of the riiesepisternum (fig. 1, lives') have diagnostic 

 value in the males. The posterior slope is densely covered with sec- 

 ondary punctures in all species, and this is usually true of a narrow 

 area posterior to the prepectus. The lower disk is usually sparsely 

 punctate at most, but on the upper disk all degrees of bipunctation 

 occur. Shagreening is also diagnostic. There are a few species in 

 which in both sexes there is a plainly visible groove (pi. 1, fig. 1) 

 adjacent and parallel to the posterior border, sometimes extending 

 upward toward the spiracle on the polished summit called the subalar 

 '-.alJ^sity . No trace of this character occurs in most species. 



The width of the impunctate apex of the scuteUum varies among 

 the males, but is rather difficult to define because the actual apex is 

 indefinite. 



On the iiietam,otiwi the principal diagnostic characters are the size 

 of the punctures as compared with those of the scuteUum and the 

 presence or absence of a medial impression or callosity. 



Legs. — The femora and tibiae are usually black, but in the females 

 of some species the femora or the tibiae, or both, are bright red. 

 Such color characters have proved constant for a long series of speci- 

 mens obtained from one locality, but may not apply so well to 

 specimens taken over a wide geographical or climatic range. The 

 presence or absence of a longitudinal groove (pi. 3, fig. 22) on 

 the hind basitarsus is an excellent diagnostic character with the fe- 

 males, and divides the species described in this paper into two nearly 

 equal parts. In the females of some species the larger of the two 

 long spurs on the hind tibia, termed its tna'jor caJcanum (fig, 1, 

 VI cal)y tapers uniformly from the base to the apex (pi. 1, fig. 4), 

 while in other species it is distinctly w^ider near the middle than at 

 the base (pi. 1, fig. 3). On the outside of the hind basitarsus 

 there occurs a group of specialized spines which range in shape from 



