SCARAB^IDAE. 243 



Tribe IV.— HYBOSORIKI. 



The mandibles and labrum are corneous, prominent; antennte 

 10-jointed, the club 3-jointed, the Grst joint hollowed and receiv- 

 ing the second; anterior coxae conical, prominent; middle coxae 

 oblique, contiguous; epinicra of the raetathorax visible; ventral 

 segments six, all but the last connate. Tarsi with a short bise- 

 tose onjchiura. 



Mandibles narrow, falciform. Hybosonis. 



Mandibles wide, outer edge angulated ; spurs of hind tibia' slioit, broad. 



and obtuse ; claws simi)le ( 9 only ?). Pachyplectrus. 



In the second genus the middle and hind tibice are much thicker 

 than in Ilybosorus, and have, like it, one very strong transverse 

 ridge on the outer side. 



Ill/bosorus arato7' is common to the Southern States and 

 Europe. Pachyplectrus is Californian. 



Tribe v.— GEOTRUPIWI. 



Insects of rounded convex form, some living in excrements, 

 others found wandering about without visible means of support; 

 the elytra strongly striate in nearly all; the thorax of some males, 

 and more rarely the head, armed with horns or tubercles. 



The mandil)les and labrum corneous, prominent; antennae 11- 

 jointed, club 3-jointed, variable in form; anterior coxjb i)romi- 

 nent; middle coxae more or less oblicpie, usually contiguous, but 

 sometimes separated; epimera of the metathorax visible; ventral 

 segments six, free; the elytra cover the pygidium; tarsi with a 

 bisetose onyehium. 



With the exception of one species each of Odontaeus and Geo- 

 trupes from California, our species are all found east of the Rocky 

 Mountains. 



Club of antennc'e large, lenticular ; 



Middle coxa? separated. Bradycinetus. 

 Middle coxje contiguous ; 



Eyes partially divided. Bolbocerus. 



Eyes entirely divided. Odontaeus. 



Club of antennffi lamellate. Geotrupes. 



