CARABIDAE. 23 



Sub-Group 1. — LebivE (genuinae). 



Head constricted behind ; menturn not distinctly toothed, emar- 

 gination more or less filled with a basal membrane;* palpi not 

 dilated. 



Tarsi dilated, spongy beneath ; 



Thorax truncate at base. Plochionus. 



Thorax pedunculate. Lebia. 



Tarsi filiform ; thorax broader behind, truncate* Nemotarsus. 



Of the last genus one species is found in the Southern and West- 

 ern States, on flowers. The Lebia? are found mostly on flowers, 

 the Plochioni under bark. The ungues are serrate in our genera. 



Sub-Group 2. — D romii. 



In these genera the head is not narrowed behind; the emargina- 

 tion of the mentum is filled with a basal membrane nearly conceal- 

 ing the tooth, when it exists ; the palpi are usually acuminate, 

 though the labial are sometimes thickened. Each genus, except 

 Trechicus, which is confined to the Southern States, has repre- 

 sentatives on both sides of the continent. The tarsi are filiform 

 in all of our genera. The species are found under stones. 



Middle tibiae with small spines ; ungues simple ; 



Palpi with last joiut oval ; third joint of antennae glabrous. 



Tetragonoderus. 

 Palpi with last joint conical ; third joint of antennae pubescent. 



Trechicus. 

 Middle tibiae not spinous ; 

 Labial palpi slender ; 

 Thorax truncate at base ; 



Mentum not toothed, ungues serrate. Dromuts. 



Mentum slightly toothed, ungues simple. Apeistus. 



Thorax slightly lobed at the base ; ungues more or less toothed ; 

 Mentum not toothed. Blechrus. 



Mentum with a small emarginate tooth. Metabletus. 



Labial palpi thick, dilated ; ungues more or less serrate. Axinopalpus. 



The species of Blechrus and Metabletus are very small, shining, 

 black insects, and were confounded together by me under the name 



* This basal membrane is the anterior portion of the mentum, which is 

 rarely seen in Carabidae, but is very obvious in many of the following 

 families. 



