320 COLEOPTERA OF NORTH AMERICA. 



group is easily recognized by the deeply channelled vertex, very 

 long % antennae, scape with an apical cicatrix, long slender legs, 

 the front pair much longer in the % ; the lower lobe of the eyes 

 is a little longer than wide. The prothorax has a strong lateral 

 spine. 



The last ventral segment in the % is feebly, in the ? more 

 strongly, truncate; the ventral segments are nearly equal in length. 



Group II. — Ptychodes. 



These have also Very elongate antennae, and slender legs, the 

 front pair elongated in the %; the vertex is deeply and narrowly 

 channelled ; the lower lobe of the eyes is broader than long. The 

 first and 5th ventral segments are longer than the intermediate 

 ones, the last is feebly truncate in the %, but more strongly in 

 the 9. The prothorax is cylindrical. 



Our genera are as follows: — 



Scape of antennse with a large well-defined cicatrix ; 



Eyes nearly divided. Ptychodes. 



Scape of antennje without cicatrix ; 



Elytra rounded at tip. Dorcaschema. 



Elytra pointed at tip. Hetcemis. 



Group III.— Goes. 



We include in this group Lacordaire's tribe Batocerini, so far 

 as it is represented in our fauna. Neither the difference in the 

 apical cicatrix of the scape of the antennte, nor the protuberance 

 of the niesosternum seem to be of tribal value. 



The body is more massive and less elongate than in the pre- 

 ceding groups. The vertex is broadly chantiellcd, the lower lobe 

 of the eyes is long in Goes, transverse in Plectrodera; the antennae 

 are but little longer than the body, and not very different in the 

 sexes; the legs are rather short, equal in length, and not different 

 in the sexes. The ventral segments are nearly equal, and the 5th 

 is more distinctly truncate in the 9. 



Three genera occuv in our fauna, all in the Atlantic region: — 



Scape of antennre with a distinctly limited cicatrix ; 



Prothorax cylindrical. Cacoplia. 



Prothorax with a lateral spine. Goes. 



Scape of antennae with the cicatrix not sharply defined ; 



Prothorax with a strong lateral spine. Plectrodera. 



