NORTH OF MEXICO. 363 



TRIBE X.\l\ — ULOMINI. 



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

 short, frequentlj broad and emarginate in front, frontal suture always distinct. Labruni 

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

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

 elongate oval. Antennae graduall) 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 iron! and the sides of the I 

 behind, never entirelj divided. Anterior coxae substransverse or sub-cylindrical, middle 

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

 Tarsi pubescenl beneath, last joint elongated. Tibial -pur- always visible, never verj 

 large. Body winged, rarely apterous. 



The tribes of the famil} Tenebrionidae 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 point- 

 of difference between the Ulomini and Tenebrionini. The Diap irini are -till 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 

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

 tinct from the Ulomini, in lieu of uniting them, a- ha- been done by Duval. It- compo- 

 sition i- here substantially that of Lacordaire, less Hypophlceus and some genera unknown 

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

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

 membrane is frequently visible in some of the genera of Tenebrionini ami Pedinini. The 

 genus Prataeus, Lee, i- found to have a faintly sub-bilobed penultimate tarsal joint and a 

 sculpture strongly recalling Anaedus, etc., and has Keen united with the Heterotarsini. 

 As defined, the tribe ha- man} genera ; some new to our fauna are now added, while 

 other- entirely new are indicated. 



The following table exhibits the character- of our genera, a- fir a- can he done in a 



-\ noptic table. 



A. Antenmr with the la-t two or three joints suddenly broader. 



Epipleurae very narrow at tip; antenna! club three-jointed. tribolium. 



Epipleurae distinct at tip; antennal club two-jointed. dioedus. 



1!. Antenna' gradually broader toward the tip. 



