Coleopterological Notices, V. 473 



kind of foveal sulcus, and the prothorax devoid of longitudinal im- 

 pressed grooves. In fact even the transverse line near the base is 

 of a structure foreign to Batrisus, being simply a fine fold of the 

 surface and not an impressed channel. 



The conformation of the base of the tergum is wholly dififerent 

 from anything ever seen in Batrisus, there being two long strong 

 carinse mutually distant by about one-half of the entire width of 

 the abdomen, each separating two large transverse impressions ; 

 so, instead of three impressions separated by two more approxi- 

 mate cusps, which is the constant condition in Batrisus, we have 

 here four impressions arranged in two pairs ; this is an extremely 

 important character from a generic standpoint. The carina?, 

 although similar to those of Bryaxis and especially Decarthron, 

 are, singularly enough, never divergent as in those genera but 

 always feebly convergent. The tarsal claws are as in Batrisus. 



It is useless to attempt to separate the species of Arthmius by 

 referring to the females, as these possess no visible characters of dif- 

 ferential value ; I have therefore based the following arrangement 

 of the four species in my cabinet upon male sexual modifications 

 alone: — 



Penultimate ventral segment transversely and deeply excavated. 



The excavation broadly rounded in front, rather abruptly defined through- 

 out and occupying nearly the entire segmental width ; ventral pygidium 

 strongly convex longitudinally, the surface ascending toward apex. 

 New York to northern Georgia globicollis 



The excavation small, with the edge ill-defined and rounded throughout, 

 not more than one-half as wide as the segment ; pygidium rather large, 

 nearly fiat ; fifth antennal joint vt^yy much larger. Texas ....l)Ul1)ifer 



The excavation large, ill-defined and rounded at the edges except ante- 

 riorly where it is broadly angulate ; pygidium nearly flat. North Caro- 

 lina illTOlllttIS 



Penultimate ventral with an extremely deep excavation longer than wide, the 



sides of which are parallel and nearly straight, with rounded ill-defined 



edges. Florida gracilior 



In many of the tropical species the head is remqrkably modified 

 in the male, but this is not the case in any thus far found within 

 the United States. The modified antennal joints five to eight form, 

 in all of our species, a more or less definite arc, and, on the under 

 surface, are clothed with much shorter stouter and more recumbent 

 setae. 



I have before me the female of two of these species, and in neither 

 Aknals N. Y. Acad. Sci., VII, Nov. 1893.— 31 



