Coleopterological Notices, V. 463 



The North Americau species hitherto placed in Triniium resemble 

 the European T. bi-evicorne in the absence of a post-humeral fovea 

 and discal stria, and, at the same time, perfectly resemble Trimiop- 

 sis eggersi in this latter feature and in the structure of the protho- 

 rax. In fact Trimium brevicorne, Trimiopsis eggerai and our own 

 Trimiuw. convexulum, duhium etc. are so extremely closely allied 

 among themselves, that they might with propriety be treated as 

 subgenera. I prefer for the present to regard our species as con- 

 stituting an important section of Trimiopsis, distinguished by the 

 absence of the post-humeral fovea. 



The male of Actium is distinguished by the large oval flat and 

 horizontal p3'gidium, almost surrounded by the anal segment, and 

 sometimes also, by setose tubercles or spicules near the sides of 

 the second and third ventral plates, both of these modifications 

 being prominent, as before noted, in several other euplectide genera 

 — for example Ramecia. Trimiopsis frequently presents the sub- 

 lateral tubercles, but in T. eggersi the flat pygidium is wholly 

 wanting. In Ramecia dentiventris the oblique pointed tubercles 

 are at the extreme sides of the third segment. 



Actium is widely diffused in Xorth America but is essentially 

 subarctic, while Trimiopsis is more especially tropical in distribu- 

 tion and probably contains a number of elements which will have 

 to be removed eventually. The species known to me may be sepa- 

 rated as follows : — 



Eljtra eacli with tliree basal fovese. 



Basal abdominal ridges fine and cariniform, generally about one-tliird as 



long as the segment and separated by about one-third of its discal 



width, larger species. 



Form more slender ; male without distinct setose tubercles near the sides 



of the abdomen, but with a minute internal subapical denticle on the 



anterior tibife. 



Head very small ; eyes much longer than the tempora ; abdominal 



carinas separated by distinctly less than one-third of the discal 



width californicum. 



Head larger, the tempora as long as the eye ; abdominal carin?e sepa- 

 rated by fully one-third of the discal widtli politllllK 



Form stouter ; male with small setose tubercles near the sides of the 



second and third ventral segments, but apparently entirely devoid 



of the subapical tibial denticle. 



Head very small, the protliorax relatively larger ; ventral pygidium of 



the male almost perfectly circular roblistullllll 



