OF THE UNITED BTATBS. 



The first division contains species living mostly on plants: the Btrongly constri 

 head sufficiently distinguishes them at first Bight: the basal membrane of the ligula is 

 thickened so as to fill up the emargination of the mentum, so that it become- verj difii- 

 cult to determine if a tooth be really present: the maxillary palpi are cylindrical in our 

 genera, and very slightly truncate at tip. They arc thus related: — 



Tarsi dilatati, subtus spongioai: thorax baai truncatua - - - riochionus /' 



Tarsi dilatati, subtus spongiosi: thorax pedunculatus I bia Lair. 



Tarsi filiformes, thorax pedunculatus - tus /. \ 



Tarsi filiformes, thorax posticc dilatatus, truncatua ... /. ■. 



In two of our species of Lebia (grand is and atriventr is,) the first three joints of 



the anterior tarsi of the male are obliquelj dilated, as in Galerita: after a v< r\ careful ex- 

 amination, I can find no character of sufficient importance to separate them as a distinct 

 genus: the mentum tooth appears somewhat larger and more prominent, but this is a de- 

 ceptive character in the present group. 



Didetus L . 

 Caput pone oculos rotundatum, basi constrictum, collo tenui oylindrioo; labrum amplum, ant 

 rotundatum, mandibular fere obtegens; palpi maxillarea labialibus Besqui longiorea, articnlo ultimo 

 precedente fere duplo longiore, leviter ovali, acuminata: antennas filiformes, articu 

 - paulo breviorc, 1-3 glabcrrimis, 4'°modicc pubescente. Thorax brevis, cordatna, | max- 



ime angustatus, basi breviasime tnbnlatim pedoncnlatns ; elytra apice trnncata. Pedes tent 

 gati, tibia; calearibua obsolctis, ungues siniplicissiini, tarsi postici articulia duoboa pi ii 



This genus is evidently related to Lionychus, but differs in not having the anterior mar- 

 lypeus elevated, and in having the head strongly constricted posteriorly. The 

 mentum-tooth of Lionychus is said to be distinct; in this genus, the middle porti in of the 

 basal membrane, filling the - nation, is corneous, but less so than the mentum itself, 



so that in certain positions the mentum appears to have a large obtuse tooth, united by a 

 suture, and in other positions to be without a tooth. Bui one Bpecies is known to me. 



I), flavipea, picco-nigcr, nitidus, tborace latitndine Beaqni ' 

 latisaimo ct latcribu3 subangulato, margine r< Bexo piceacente, elytria dnplo latioribua, 



pedibus flavo-testaccis. Long. IT. 



Louisiana, Mr. Guex. The antenna' arc entirelj black, the palpi piceous, the ligula 

 and adjoining parts pale. 



/. . 



I ipnt pone ocnlos rotundatum et vahle constrictum, coll" tend cylindrioo; labrum qnadratam, 

 angustum : palpi maxillarcs labialibus duplo longiorea, articnlo ultimo pra cedente duplo 

 nico. kto, labialea articnlo ultimo leviter ovali, acnto : mentum dente magno indiat 



n.-e filiformes, articulia Bequalibua, 2"' 1 " seaqui breviore. Thorax Bemioircularia, baai tmni 

 trnncata. P tibim calearibua elougatis, ungue 



po3tici articulia l-l gradatira brevioribus. 



