O.ajtclus.'] STAPnyuNiD/B. 377 



last joint of maxill.ary palpi shorter than 



pcnulthnate 0. LAQUEATVS, Marsh. 



B. Forehead with one longitudinal central fur- 

 row ; last joint of maxillary palpi as long as 



or lonj;^er than penultimate 0. PICEUS, L. 



ii. Elytra without impressed stria and ridge at sides ; 



hind hody without distinct outstanding bristles ; 



elytra usually black or pitchy. 



1. Head, thorax, and elytra shining. 



A. Antennre black or blackisli. 



a. Forehead somewhat convex, very smooth; 



vertex of head not or only indistinctly 

 foveolate ; upper surface black, very 

 shiny O. INUSTUS, Orav, 



b. Forehead depressed; vertex of head dis- 



tinctly foveolate. 



a*. Length 31-4 mm.; elytra unicolorous 

 black or dark brown ; upper surface 

 moderately shiny O. 8CULPTUBATUS, Orav. 



b*. Length 2| ram. ; elytra with disc red- 

 dish ; upper surface very shiny . . . O. NlTiDaLUS, Grav. 



B. Antennae reddish ; elytra black or testaceous. 0. MAIUTIMUS, Thorns. 



2. Head, thorax, and elytra (except sometimes 



front of head) dull. 

 A. Length 3 mm. ; forehead quite dull ... 0. complanatus, Sr. 

 U. Length 1^-2 mm. 



a. Head dull with clypeus very shiny ; elytra 



longer; autenn EC more slender . . . . 0. cltpeonitens, Pa/u?. 



b. Head dull with the autenual projections 



and two little spots on vertex more shiny ; 



elytra shorter ; antenna) stouter . . . O. speculifrons, Kr. 



{nee Rye). 



c. Head entirely dull. 



a*. Anterior tibife entire O. teteacaeinatus. Block. 



b*. Anterior tibiaj emarginate at apex . . O. Faikmaieei, Paiid. 



O. rug"osus, Grav. Depressed, somewhat parallel- sided, black, 

 rather shining with hind body duller ; head considerably broader in male 

 than in female, with a dull depressed space before eyes which is finely 

 shagreened, hinder part shining and punctured ; antennae rather short, 

 dark with the first four joints pitchy red, penultimate joints scarcely 

 transverse ; thorax transverse, thickly and rather strongly punctured, 

 rounded and narrowed behind, Avith the central furrow distinct in front, 

 and the side ones more distinct behind ; elytra transverse a little longer 

 than thorax, depressed, rugosely punctured, the punctuation forming 

 three or four striae at sides ; hind body nearly as broad as elytra, very 

 finely punctured ; legs variable, lighter or darker pitchy red. L. 4-5 

 mm. 



Male with seventh ventral segment of hind body deeply bisinuate on 

 apical margin, the central lobe being prolonged almost to a level with 

 the lateral ones, sixth segment with three or four obsolete small teeth in 

 middle of margin, fifth and sometimes fourth and tliird with a rather 

 strong tubercle at apex ; in the female, as is the case with almost all the 



