SCARAB^IDAE. 239 



Epimcra of metatliorax covered ; 



Antennre 9-jointed. Aphodiini. 



Antennae lO-jointwl. Okphnini. 



Iilpimera of metatliorax visible. Hybosokini. 

 Antennae 11-jointed ; 



Club 3-jointed, mandibles and labrum prominent. Geotrupini. 



Club many-leaved, mandibles and labrum small. PiiEOCOMiNi. 

 Abdomen with five visible ventral segments ; 



Epimera of mesotliorax attaining the oblique coxae ; 



Body contractile, legs broad. Acaxtiiocerini. 



Body not contractile, legs normal. Nicagini. 



Epimera of mesotliorax not attaining the rounded coxae. Trooini. 



Tribe I.— COPRliVI. 



These insects are of rounded form, :ind live almost exclusively 

 in excrements. The clypeus is expanded so as to cover entirely 

 the oral organs; the lobes of the maxillaj are large, ciliated, and 

 of a membranous or coriaceous structure; mandibles lamelliform, 

 principally membranous, with oidy the outer margin corneous; the 

 nientum is emarginate; antenna? 8- or 9-jointed, club .S-jointed ; 

 epimera of metathorax covered; mesosternum very short; middle 

 coxffi oblique, widely separated ; posterior tibite with a single ter- 

 minal spur, except in Ganthon indigaceus and nigricornis, where 

 the hind tibia' have two; tarsi usually without the bisetose ony- 

 chium; elytra subtruncate, leaving the pygidium exposed; ven- 

 tral segments six, all connate. 



It is in this tribe alone that species occur in which the anterior 

 tarsi are wanting in the females, or in both sexes; the claws of 

 the tarsi arc also sometimes wanting. Organs of stridulation are 

 found on the dorsal surface of the abdomen of certain species. 



According to the form of the posterior tibiae, two sub-tribes 

 are indicated. 



Middle and posterior tibiae slender, curved, scarcely enlarged. Ateuciuni. 

 Middle and posterior tibi;e dilated at the extremity. ("oprini. 



Sub-Tribe 1. — AteUCllilli. 



These species deposit their eggs in balls which they construct 

 of the materials on which they live, and roll these balls to a 

 considerable distance, a labor for which their long, slender, and 

 slightly curved posterior tibias fit theuK The head and thorax 

 never bear horns, and the sexes are alike in appearance, except 

 in Dcllochilum gihbo-sum, where the elytra of the male are each 



