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 iowanns n. 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 iowa- 

 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. 



Orns 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 Scojyaeus 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 ScojMeus, which — if we except a small aberrant form 

 recently named Lep)torus longijjennis , 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 2 



Neck very slender as in Scopaeus 14 



2 Prothorax elongate, never more than slightly shorter than the elytra . . 3 



Prothorax invariably very much shorter than the elytra 5 



3 — Sides of the prothorax, from the obtusely rounded apical angles to the 

 base, distinctly converging and straight. Body very slender, black 



