1873.] ZbO [Horn. 



Thorax at sides smooth, bistriate, strire entire, equal, straight. Elytra 

 with three entire strite, fourth slightly abbreviated at base, fifth short, 

 apical, sutural extending in front of middle, subhumeral entire. Pro- 

 pygidium coarsely but sparsely punctured, pygidium more finely and 

 sparsely punctured, neai'ly smooth at apex. Anterior tibiae sub-5-den- 

 tate, apical tooth shorter than second and slightly bifid. Length .30-.26 

 inch ; 5-6.5 mm. 



Middle and Western States, common. 



H. stygicus, Lee. Bost. Journ. V., p. 48, pi. 2, fig. 4; Mars. Mou., 

 1854, p. 301, pi. 9, fig. 94. 



There are absolutely no characters on which to separate this species 

 from interruptug excepting the following : 



Sjiecies much smaller, form more broadly oval, thoracic strife entire, 

 parallel and eqni-distant from each other, and from the margin. Elytral 

 striae exactly as in inter ruptus. Propygidiura coarsely but very sparsely 

 punctulate, pygidium shining very minutely and sparsely punctulate. 

 Length .10 inch ; 2.5 mm. 



The species is described as having four entire striae, the fourth stria is 

 abbreviated at base. Marseul mentions a basal arc opposite the fifth 

 stria ; this may or may not be present in any species of this group. The 

 head is said to have an impressed point at middle of front ; of the two 

 typical specimens one has it, the other has not. 



Two specimens from Georgia. 



H. immunis, Er. Jahrbuch, 1834, p, 143. 



Sides of thorax bistriate, striae entire, parallel and straight. Elytra 

 with three entire striae, fourth slightly abbreviated at base, fifth very 

 short, apical, sutural either very short or entirely obsolete, subhumeral 

 entire. Propygidium coarsely and evenly punctured, pygidium more 

 finely punctured especially at apex. Anterior tibiae sub-5-dentate, 

 apical tooth shorter. Length .20 inch ; 5 mm. 



Occurs in the Middle States, and also in California. 



Group Foedatus. 

 Inner thoracic stria entire or very nearly so, outer either entirely absent 

 or very much abbreviated. Anterior tibiae multidentate. 

 Thoracic margin thickened, inner stria, entire ; epipleurae 



unistriate marginicollis. 



External thoracic stria entirely obliterated. 



Thoracic margin not thickened. 



Stria posteriorly abbreviated ; epipleurae unistrate. . . . cognatus. 



Stria 'entire ; epipleursB bistriate remotu?. 



External thoracic visible, usually very short, rarely half the 

 length of the inner. 

 Inner stria slightly abbreviated at tip ; epipleurte uni- 

 striate .* foedatus. 



