COLEOPTEEA. 



ADEPHAGA. 



( CARNirORA—FILICOBNIA. ) 



The classification of this series has always been attended with con- 

 siderahle difficulty, and cannot yet be said to be settled. The best method 

 appears to be that adopted by Dr. G. H. Horn, in his essay on the genera 

 of Carabidte, published in the Transactions of the American Entomological 

 Society for 1881.* Dr. Sharp (Trans. Ent. Soc. London, 1882, i. Gl) 

 suggests certain alterations in the system ; the most important of these 

 are included in the table given below. The series contains only a few 

 families, the members of which are, as a rule, active ; in habits they are 

 predaceous and carnivorous. Part of them are terrestrial and part 

 aquatic, and in conformity with their habitat many authors divide them 

 into two groups, styled respectively Geodephaga and Hydradephaga. It 

 is, however, better to treat them as a whole. For further particulars the 

 student of the group would do well to consult the papers above referred 

 to, the section Carabidas by Mr. Bates lately published in the " Biologia 

 Central!- Americana," and the work of Dr. Sharp " On Aquatic 

 Carnivorous Coleoptera or Dytiscidaj " published in the Transactions of 

 the Royal Dublin Society for 1882, 



In the following table the comparatively recently discovered JsTorth 

 American family, Amphizoidce, is included as forming a strong con- 

 necting link and transition between the ordinarily received sections of the 

 series. 



I. Mctasternum with an ante-coxal piece, separated by a well-marked 



suture, reaching from one side to the other, and extended 

 triangularly between the hind co.\a3. 

 i. AntenuEc eleven-jointed; posterior coxaj free and simple; 

 habits terrestrial. 



1. Clypeus extending laterally on both sides in front of and 



beyond the insertion of the antenna) Cicindelidj;. 



2. Clypeus not extending so far towards the sides as the 



insertion of the antenna' Cababid^. 



ii. Antennae ten-jointed ; posterior coxa) fixed and furnished with 

 large plates, covering a great portion of the abdomen ; habits 

 aquatic HALirLlD.E. 



II. Mctasternum with a very short ante-coxal piece, the suture in- 

 distinct, not prolonged posterioi-ly between the hind coxso ; habits 

 aquatic. 



* This observation applies only to Dr. Horn's general arrangement of the families 

 of the Adcphaga, and not to his detailed classification of the Caraljidic. 



B 



