RHIPICERIDAE. 175 



A family of small extent ; three genera of the tribe of genuine 

 Cebrionidse are represented in our fauna ; Cebrio, in the Southern 



\ States ; Anachilus in Florida ; Scaptolenus in Texas ; they are 

 found flying about at night. The females are found at the en- 

 hance of holes which they excavate in the ground. 



Labruni entirely connate with the front. Anachilus. 

 Labrum separated by future from the front ; 



Anterior tibiae entire. Cebrio. 



Anterior tibiae emarginate externally. Scaptolenus. 



The principal differences between this and the preceding family 

 is in the greater number (six) of ventral segments, the well de- 

 veloped tibial spurs, the expansion of the anterior tibiae at the 

 apex, and the close connection between the front and the labrum. 

 By the intermediate forms of the group Plastoceri, of the pre- 

 vious family, all the differences, except those of the anterior tibiae, 

 become evanescent ; and I place the Cebrionidae as a distinct 

 family, only in deference to the views of the most distinguished 

 foreign authorities. 



Fam. XXXVIL— RHIPICERIDAE. 



Mentum quadrate, corneous; ligula small, not prominent; 

 palpi 3-jointed. 



Maxilloe exposed at the base; usually with but one lobe; 

 palpi 4-jointed. 



Antennae inserted before and inside of the eyes, under 

 ridges, 11-jointed (in our genera), serrate in the females, fre- 

 quently flabellate in the males. 



Head prominent: eyes round; epistoma not distinct; labrum 

 indistinct; mandibles large, stout and prominent in Sandalus, 

 small in Zenoa. 



Prothorax with the side pieces not separate ; coxal cavi- 

 ties large, transverse, open behind ; prosternum not pro- 

 longed. 



Mesosternum short, oblique, flat; side pieces attaining the 

 coxae. 



Metasternum short in Sandalus, moderate in Zenoa; side 

 pieces wide in the first, narrow in the second ; epimera large 

 in Sandalus, not visible in Zenoa. 



Elytra covering the abdomen ; epipleurse extending to the 

 apex. 



