224 GEO. H. HORN, M. D. 



Before proceeding to the consideration of the tribes the following 

 remarks ou the geographical distribution of the genera may be of 

 interest. 



There are 43 genera recognized in the following pages distributed 

 in the tribes as follows : 



Silphini 8 of which there are new 1. 



Lyrosomini 1 " " " 0. 



Pinodytini 1 " " " 1. 



Cholevini 16 " " " 2. 



Anisotomini 14 " " " 1. 



Clambiiii 3 " " " 0. 



In the second tribe Lyrosoma has been revived from its improper 

 suppression in Pteroloma. In the fourth tribe I have suggested the 

 suppression of Drimeotus in Pholeuon. Catopomorphus in Ptomaphagus, 

 Quccsticulus and Qusestus in Bathyscia; the last three had been 

 suppressed in Adelops. With these explanations a concordance is 

 established with the Catalogus, excluding Leptinus and Sphajrius 

 from the family. In addition to the new genera of the present paper 

 six others have been published since the Catalogus. 



Of the above genera 



North America has represented 30. 



Peculiar to North America 10. 



Europe has represented « 27. 



Peculiar to Europe 10. 



Common to Europe and North America IS. 



Common to Alaska and Kamtschatka {Lyrosoma) 1. 



Peculiar to India [Apatetica) 1. 



Peculiar to New Zealand {Camirus) 1. 



Peculiar to Madeira (Stereus) 1. 



Peculiar to Brazil (Scotocryjitus) , 1. 



By the above scheme it will be observed that the genera with 

 four exceptions belong to Europe and North America, that each has 

 nearly an equal number represented and with the same ratio of those 

 peculiar to it. 



The number of species described from Europe nearly doubles that 

 from our own fauna. 



Tribe I, — Silphini. 



Anterior coxse conical, prominent, contiguous, with large trochantin, the 

 cavities strongly angulate externally and open behind, very widely in Necro- 

 phorus and Silpha and partially closed in the other genera. Middle coxae widely 

 seiaarated in these two genera, narrowly separated or even contiguous in the 

 others. Posterior coxse contiguous. Abdomen with six segments except in 

 Sphcerites. Antennae variably inserted, sometimes free at base or under a 

 slight frontal margin. 



