of the Icss-knoivn groups of Lamellicorn Gohoptera. 485 



Antennal club of 3 joints. 



i Labrum and mandibles horizontally ex- 

 truded, flattened. 

 A Eyes divided in front. 



Labrum as long as mandibles .... Aclopinae. 

 Labrum shorter than mandibles. 



Antennae 11-jointed Geotrupinae. 



Antennae 10-jointed. 



Antennal club telescopic, joints cu- 



puliform Hybosokinae. 



Antennal club simple, lamellate. 

 Stridulating plate in hind coxal 



cavity Taurocerastinae. 



Stridulating plate on hind coxa . Orphninae. 



Antennae 9-jointed Chironinae. 



<x- Eyes entire Ochodaeinae. 



1 Labrum and mandibles not horizontally ex- 

 truded. 

 Antennae 10-jointed. 



Labrum very small Idiostominae. 



Labrum large Troginae. 



' Antennae 8- or 9-jointed. 



Hind tibia 2-spined : mid-coxae contiguous Aphodiinae. 

 Hind tibia 1-spined : mid- coxae separate . Coprinae. 



In this scheme of classification, most of the diagnostic 

 characters introduced by Ericiison and adopted by La- 

 cordaire and all later systematists have been abandoned. 

 The number of visible ventral segments in the abdomen 

 was employed for a primary division by Erichson ; and 

 althoiigh both Lacordaire and Westwood remarked that 

 it was scarcely of sufficient weight for the purpose, neither 

 ventured to reject it, and the occurrence of five segments 

 only has remamed the criterion of the Troginae and led 

 to the wide separation of genera very nearly allied. The 

 visibility or otherwise of the metasternal epimera, similarly 

 used for the separation of the Laparostict sub-families, is, 

 like the number of recognizable ventral segments, subject 

 to gradual transition and no more capable of application 

 as a sharp dividing line. My study has thus led to a 

 certain fresh delimitation of frontiers and re-arrangement 

 of the component genera of certain sub-families, especially 

 the Hyhosorinae and Troginae, which it is necessary to 

 define. 



