N0UT1I OF MEXICO. 



363 



TRIBE X XIV — IT LOM INI. 



Body elongate oval, usually somewhat depressed. Head deeply inserted in prothorax, 

 short, frequently broad and emarginate in front. Frontal suture always distinct. Labrum 

 usually prominent, transverse. Mentum variable in most of the genera, trilobed, with the 

 middle lobe prominent. Maxillary palpi with the last joint usually triangular, sometimes 

 elongate oval. Antennae gradually thickened toward apex, (rarely with the terminal 

 joints forming a club) and more or less perfoliate ; third joint not very long. Eyes vari- 

 able, always more or less emarginate by the sides of the front and the sides of the head 

 behind, never entirely divided. Anterior coxae sub-transverse or sub-cylindrical, middle 

 coxae without trochantin. Intercoxal process of abdomen acute or oval, never broad. 

 Tarsi pubescent beneath, last joint elongated. Tibial spurs always visible, never very 

 large. Body winged, rarely apterous. 



The tribes of the family Tenebriouidee are all difficult of definition, and no one is pro- 

 bably more troublesome than this one, and it is only on the table of characters given 

 above, taken as a whole, that the tribe must be considered as limited. In the structure 

 of the antenna" and the absence of trochantin to the middle coxae, we find the only points 

 of difference between the Ulomini and Tenebrionini. The Diaperini arc still less distinct, 

 for with a form of antenna, not unlike (though at times sub-serrate) we find the structure 

 of the front offering the most striking points of difference. In Diaperini the eyes are 

 always round, prominent, feebly emarginate in front and always more prominent than the 

 gense. In the course of the study it has seemed advisable to preserve the Diaperini dis- 

 tinct from the Ulomini, in lieu of uniting them, as lias been done by Duval. Its compo- 

 sition is here substantially that of Lacordaire, less Eyp'ophhxus and some genera unknown 

 to him by specimens. The tribe Hypophloeini of Leconte appears to me untenable, the 

 character defining it, the invisibility of the clypeal membrane, is not constant and the 

 membrane is frequently visible in some of tin 1 genera of Tenebrionini and Pcdinini. The 

 genus Pratseus, Lee, is found to have a faintly sub-bilobed penultimate tarsal joint and a 

 sculpture strongly recalling Amedus, etc., and has been united with the Heterotarsini. 

 As defined, the tribe has many genera, ; some new to our fauna are now added, while 

 others entirely new are indicated. 



The following table exhibits the characters* of our genera, as far as can be done in a 

 synoptic table. 



A. Antenme with the last two or three joints suddenly broader. 



Epi pleurae very narrow at tip; antenna! club three-jointed. T.RIBOLIUM. 



Epipleune distinct at tip; antennal club two-jointed. dkedus. 



B. Antennas gradually broaden- toward the tip. 



