NORTH OF MEXICO. 



331 



sections. From the Scaurini this tribe may be distinguished by the absence of spines in 

 the vestiture of the tarsi, from the Amphidorini by the rather dense, long, coarse hairs 

 forming the vestiture in that tribe. The Ulomini are nearly all deprived of trochantin to 

 the middle coxee, (lie third joint of antennae usually short, the head deeply inserted in a 

 prothorax more deeply emarginate in front. 



The tribe here defined lias undoubtedly more complex; relationships and affinities than 

 are found in any other tribe. The genus Polypleurus points strongly toward the Scaurini, 

 Tenebrio towards the; Ulomini, Glyptotus in the direction of llelops, and Xylopinus 

 (irnoseens) toward the Strongyliini. A careful revision of the genera, of the world would 

 undoubtedly cause an entire rearrangement of the genera,, especially in those of the second 

 sub-tribe, and their apportionment in new tribes. 



Two sub-tribes are here recognised. 



Tarsi densely clothed with line, short, silken pubescence. 



Tarsi rather sparsely clothed with coarse pubescence. 



UPBB. 



TENKHIUONES. 



SUB-TRIBE I — UPES. 



The species of this group are all of moderate or large size, and are comprised in genera 

 containing but few species. Among the Upes Ave find genera, varying greatly from the 

 type, showing strong affinities toward tribes of lower grades in their general organization. 

 These degradations of structure are the more evident among the last four genera, where 

 the antenmr assume a form closely allied to that of llelops, while in two of the genera 

 the anterior tarsi are slightly though very distinctly dilated in the males. The pubes- 

 cence of the tarsi loses that fine silken or velvet-like appearance and approximates that 

 seen among the species of the second sub-tribe. The mentum varies greatly in all tin; 

 genera,, in some being flat and round, in others trilobed or convex at middle. The epi- 

 pleuree are usually abbreviated, in some few genera entire. The mctasternum is long or 

 short, in accordance with tin; presence or absence of wings. The hind coxa- arc some- 

 times widely, usually narrowly, separated by a triangular or oval intereoxal process. 



In accordance with the variations of structure thus indicated briefly, our genera may 

 be tabulated as follows: 



Antenna? with the outer joints transverse, perfoliate- last joint sub-quadrate, rounded at 

 tip and larger than the preceding; antenme shorter than the head and thorax. 

 Epipleuree entire. 



Epipleimc not narrower at apex. POLYPLEURUS. 



Epipleuree gradually narrowing to apex. 



Mentum with small lateral indexed lobes. NYCTOBATES, 



Mentum without lateral lobes. IPHTHIMUS. 



