NORTH AMERICAN COLEOPTERA. 67 



This species seems to bear the same relation to the others of the 

 genus that Oxyomus porcahis does to the mass of Aphodii. In look- 

 ing at the thorax from above, the sides of the base are so very ob- 

 lique that the effect is produced of the thorax being rather abruptly 

 coarctate at base. 



Occurs from Canada and New England States to Maryland and 

 Illinois. 



AT.EIVIUS Harold. 



This genus was suggested by Baron Harold in 1867 for certain 

 species previously placed in Euparia. The following are the char- 

 acters given : 



Head convex, not tuberculate. Mandibles concealed, the molar 

 tooth distinct, lamina} membranous. Maxillary lobes membranous. 

 Eyes usually concealed, ventral segments united, the terminal sepa- 

 rated from the })receding by a deeper groove. jNIesosternum carinate. 

 Pygidium free, deflexed. First joint of hind tarsus elongate, of the 

 anterior tarsus, longer than the second. Posterior tibise simple, with- 

 out transverse carina?, straight. Allied to Euparia, differs by the 

 posterior tibite not arcuate, metasternum not abbreviated, sides of 

 thorax not explanate. 



The outer apical angle of the hind tibije is always more prolonged 

 than in Aphodiii-'<, and often spiniform. In all or nearly all the spe- 

 cies the sides of the thorax are fimbi-iate, but the hairs are so easily 

 lost and often so short that no account is taken of them in the fol- 

 lowing descriptions. The mesosternum is usually furnished with an 

 obtuse polished carina between the coxse, but this is not present in 

 several species and feeble in others. The metasternum at middle 

 has a deep groove, present in all the species. The first joint of the 

 anterior tarsus is always longer than the second. The pygidium is 

 in part exposed beyond the elytra and is divided by a transverse 

 elevated line, the exposed portion below this line is eroded and usually 

 filled with dirt, the portion above is finely punctured, and has a deep 

 median groove into which an inflexed edge of the elytron is inserted 

 in the manner already indicated for Ochodceus. 



The sculpture of the elytra in many of the species is peculiar in 

 the appearance of the stri:o. These appear often coarsely punctured, 

 when a look into the stritv shows that the punctuation is really fine 

 and distant, the dec(>ption arising from the sides of the intervals 

 being crenate. It will also be observed that this crenation is entirely 

 independent of the punctures of the striio and not caused by them. 



