196 Trans. Acad. Sci. of St. Louis. 
arcuate at the sides; sutural region broadly impressed throughout; 
abdomen parallel, obviously narrower than the elytra. Length 3.25 
mm.; width 0.73 mm. Male unknown. Iowa.........-iOWANUS ND. sp. 
There is a small, rounded and acutely pointed tubercle at 
the middle of the gular intersutural surface, just behind the 
oral cavity, which seems to be obsolete in the female of 
dentiger, but it is present in the unique female type of cowa- 
nus. ‘The latter species is very distinct from the others in 
its much larger elytra and more broadly and evenly rounded 
basal angles of the head. The characters of armiger are 
taken from the original description of Mr. Fall. 
Orus Csy. 
The numerous species of this genus are of slender form 
and more or less shining surface, due to the sparse and 
coarser punctuation, they being distinguished from Scopaeus 
by this character as well as the broader neck and other fea- 
tures mentioned in the table. Cervicula constitutes a remark- 
able exception in regard to one of the most important struc- 
tural characters distinguishing the genus from Scopaeus and 
several other genera of the group, the neck being very slender 
and precisely similar to that characterizing the genus men- 
tioned. In all its other characters, however, it is a typical 
Orus and cervicula cannot, therefore, be held to unite Orus 
with Scopaeus. In geographical range Orus is confined to the 
regions bordering the Pacific Ocean, not penetrating east- 
ward, as far as known, further than the crest of the Rocky 
Mountain divide. The species are larger and stouter than 
those of Scopaeus, which—if we except a small aberrant form 
recently named Leptorus longipennis, by Mr. Fall, — does 
not form a part of the true Pacific coast fauna. The species 
known thus far may be defined as follows :— 
Neck of the usual width, nearly a third as wide as the head.......... ee 
Neck very slender as in Scopaeus..cceccsesccesccescceccce cece sesessccceeld 
2— Prothorax elongate, never more than slightly shorter than the elytra.. 3 
Prothorax invariably very much shorter than the elytra.......csececeeees 5 
8 — Sides of the prothorax, from the obtusely rounded apical angles to the 
base, distinctly converging and straight. Body very slender, black 
