234 GEO. H. nORN, M. T). 



It8 habitat is Kansas and Colorado, south of the flatto River, soiithwesterw 

 Arkansas, Indian Territory, probably northern Texas, New Mexico and east- 

 ern Arizona. 



09IUS, Esch. 



Male. — Three joints of anterior tarsi dilated, (the dilatation not 

 bilateral, but more internal than external), and densely aponjry pubes- 

 cent beneath. Last ventral segment deeply emarginate at middle. 



Femnle. — Last ventral segment oval at tip and entire, and with a 

 marginal groove composed of large deeply impressed punctures, each 

 bearing a short seta. 



TETR.iCIIA, Hope. 



Male. — Anterior tarsi dilated as in Omus. Last ventral segment 

 broadly triangularly emarginate. Tip of elytra sub-truncate, sutural 

 angle rectangular. 



Female. — Last ventral segment broadly oval at tip. Tip of each 

 elytron rounded, sutural angle obliterated. 



€ICIx\DEL,A, Linn. 



General sexual characters. 



Male. — Three joints of anterior tarsi dilated, with short silken pubes- 

 cence beneath. Last ventral segment broadly emarginate. Middle 

 tibiae pubescent on the outer side. 



Female. — Anterior tarsi slender. Last ventral segment longer than 

 in the male, slightly compressed at the sides, posterior half with a 

 longitudinal impression varying in depth according to the species. 

 Middle tibiae glabrous. 



The emargination of the sixth ventral segment of the male allows 

 the seventh segment to become very plainly visible, divided into two 

 symmetrical portions, the left overlapping the right, the whole con- 

 stituting by this modification part of the genital armature. 



A careful examination of the females of certain species convinces 

 nie that the last ventral segment is composed of parts which represent 

 the sixth and seventh segments of the male. That portion which 

 correspDiids with the sixth of the male may be seen distinctly defined 

 by an obsolete suture in those species in which the abdomen is rufo- 

 testaceous, (man/iniprnnis, etc.), and the seventh segment of ttie male 

 is that portion of the female sixth in which the longitudinal impres- 

 sion is included, the bottom of the impression representing tlie joint 

 of the halves of the male segment. 



In addition to the sexual characters above given, and which are 



