SCARABJEIDAE. 127 



of raetathorax covered ; middle coxos oblique, contiguous in our 

 genera ; posterior tibiae with two spurs ; elytra covering the py- 

 gidium entirely or in part; ventral segments six, all free; tarsi 

 with distinct claws and small bisetose onychium. 



The sexual differences are usually none ; in a few species the 

 head, and more rarely the thorax, of the male are marked with 

 one or more small tubercles. Our genera are as follows : — 



Mandibles and labrum concealed ; 

 Lobes of the maxillae membranous or coriaceous, unarmed ; 



Upper part of the eyes visible in repose. Aphodius. 



Upper part of the eyes invisible in repose ; 



Posterior tibia? prolonged externally into a spine. Eupakia. 



External lobe of the maxillae corneous, hooked. Psammodius. 



Mandibles and labrum visible beyond the clypeus. -ZEgialia. 



Euparia embraces many species, of which Eu. castanea inhabits 

 ants' nests in the Southern States. Psammodius is recognized by 

 the transverse grooves of the thorax, and ^Egialia by the thick 

 convex body ; the species of the last-named genus are found near 

 the ocean or large lakes. 



Several species of Aphodius have been introduced from Europe, 

 but are now entirely naturalized, especially in the northern parts 

 of the country ; e. g. A. fossor, fimetarius. 



Tribe III.— ORPHNIOT. 



Oval, convex species, of brown color, covered above with short 

 erect hair ; the elytra are striate ; the mandibles and labrum are 

 corneous, not covered by the clypeus, which is not dilated as in 

 the two preceding tribes ; antenna3 10-jointed, club 3-jointed, some- 

 what rounded; anterior coxa? prominent; middle coxa? oblique, 

 contiguous; epimera of the metathorax covered ; ventral segments 

 six, not connate ; tarsi with a small setigerous onychium. 



The species in our fauna are three, belonging to Ochodseus. 

 They are found from the Mississippi westward to Arizona, and 

 are very rare. Ochoda3us is distinguished from the other genera 

 of the tribe by the eyes being not emarginate. The habits are 

 unknown. 



Tribe IV.-IIYBOSORIIVI. 



A single species of Hybosorus found in the Southern States, 

 identical with the European H. arator, and probably imported, 



