462 Coleopterological Notices, V. 



abruptly defined, giving the appearance of two short divergent 

 striae. Although the abdomen is impressed at base, the carinse 

 appear to be entirely obsolete. 



The two forms known to me resemble each other closely in all 

 generic characters, but are quite different specifically, as may be 

 inferred from the following statement: — 



Head larger, almost as wide as the prothorax, the frontal margin deeply in- 

 terrupted in the middle ; eyes slightly smaller ; prothorax less transverse, 

 more broadly rounded and parallel at the sides, the latter strongly conver- 

 gent and sinuate only in basal third ; size very minute, 0.75 mm. Missis- 

 sippi Valley Cavifrons Lee. 



Head smaller, very much narrower than the prothorax, with the frontal mar- 

 gin feebly interrupted ; prothorax more transverse, much more strongly 

 rounded laterally before the middle, the sides strongly convergent and 

 broadly sinuate in basal half; size appreciably less minute, 0.85-0.9 mm. 

 Texas laticolle Csy. 



ACTIUM Casey. 



This genus is closely allied to Trimiopsis Reit., but the species 

 are generally larger and have a distinct discal stria on the elytra, 

 while in Trimiopsis the discal stria is wanting. It is further dis- 

 tinguishable at once from Trimiopsis by the structure of the pro- 

 thorax, the disk of the pronotum having two subbasal foveas and 

 rather well-defined lateral edges in Actium, while in Trimiopsis 

 there are no definite lateral foveae or edges, the transverse sulcus 

 being continuous down the vertical flanks, gradually disappearing 

 beneath. 



Both Actium and Trimiopsis eggersi — assumed here as the type 

 — are easily distinguishable from Trimiiim brevicorne by the pres- 

 ence of a post-humeral fovea and pleural sulcus on the elytra, a 

 character apparently of some importance. The basal foveae of the 

 elytra are however of no value generically in this group, and are 

 often inconstant, one specimen before me having two foveae on one 

 elytron and three on the other. There are species having either 

 two or three fovese, not only in Actium, but in Eupleetus and 

 Ramecia. As an instance of the importance of the post-humeral 

 fovea, however, Trimiopsis specularis Reit. may be cited. This 

 species lacks the fovea completely, and is further distinguished by 

 its shorter and stouter tarsi, and by a singular antennal character, 

 the eleventh joint being split at apex in both sexes, the two segments 

 apparently mobile. 



