TENEBRIONIDAE. 233 



Our genera may be distinguished as follows : — 



Antennae with the last three joints suddenly larger. Tribolium. 



Antennae with the outer joints gradually larger; 

 Epipleurae not reaching the tip of the elytra ; 

 Front tibiae slender ; 



Outer joints of antenna? trapezoidal. Gnathocerus. 



Outer joints of antennse transverse, rounded; 



First joint of hind tarsi long. CynjEUS. 



First joint of hind tarsi short. Thaesus. 



Front tibiae dilated, serrate. Uloma. 



Epipleurae extending to the tip of the elytra; 



Front tibiae dilated, finely denticulate. Alphitobius. 



Front tibiae slender ; 



Menturn trapezoidal. Ulosonia. 



Mentuni with small, lateral, infiexed lobes. Neatus. 



Front tibiae dilated, not denticulate. Aphanotus. 



Tribolium and Gnathocerus are represented by species carried 

 by commerce over the whole globe. The type of Cynseus is Pla- 

 tydema angustum Lee, from the Colorado Desert of California ; 

 it resembles in appearance and sculpture Alphitobius, but is much 

 less convex, being, in fact, almost flat. Tharsus is founded on a 

 sub-depressed, elongate species of dark ferruginous color ('20 unc. 

 long) ; the thorax is almost as long as wide, strongly punctured, 

 with the sides narrowly but strongly margined ; the strise of the 

 elytra are distinctly punctured, the intervals are slightly convex, 

 and finely but not densely punctulate : it is found in the Southern 

 States, and I have named it T. seditiosus; it resembles in appear- 

 ance Uloma ferruginea Say, but is smaller and narrower. To 

 Ulosonia must be referred Uloma marginata Lee, from the 

 Colorado Desert of California. Neatus is established upon He- 

 lops tenebrioides Beauv. (Tenebrio badipes Mels.), a common 

 insect of the Atlantic States ; the middle coxae are almost closely 

 surrounded by the sterna, and the trochantin is obsolete, as in 

 TJloma. The type of Aphanotus is Eulabis brevicornis Lee, 

 from California ; it resembles very much in sculpture Eulabis, 

 but differs by the metasternum being long and the body winged. 



I have removed from this tribe several of the genera placed in 

 it by Lacordaire, as they differ in having a distinct clypeus be- 

 tween the epistoma and the labrum. 



