96 COLEOPTERA OF NORTH AMERICA. 



A. Maxillary j^alpi with the fourth joint shorter than the tliird ; 

 Thorax smooth, narrowed at the base ; 2. 

 Thorax punctured, pubescent, narrowed at the base. Listotrophus. 



2. Middle coxae contiguous, suture imbricated, wings none. Thinopinus. 

 Middle coxse distant, suture straight. Creophilus. 



B. Maxillary palpi with the fourth joint equal to or longer than the third ; 

 Marginal lines of the thorax separate, wings distinct, last joint <yi labial 



palpi truncate. 2. 



Marginal lines of the thorax separate, wings none. Hadrotes. 



Marginal lines of the thorax imited near the apex, body winged ; 3. 



2. Marginal lines closely approximated in front, the inner indistinct 



anteriorly. Trigonophorus. 



Marginal lines distant in front, the inner well defined. Xanthopygus. 



3. Ligula emarginate ; 4. 

 Ligula entire ; ti . 



4. Middle coxfe slightly separate ; abdomen narrowed at tip (thorax i^unc- 



tured, pubescent). *Staphylinus. 



Middle coxjb contiguous ; abdomen very long, parallel. Ocypus. 



5. Femora unarmed. (i. 

 Femora spinous beneath. Belonuchus. 



6. Last joint of labial palpi securiform. Euryporus. 

 Labial palpi slender. Philonthus. 



Sub-Tribe 3. — Xanttioliuini. 



The antenntB are inserted near the middle of the anterior mar- 

 gin of the front, and approximated ; they are geniculate in our 

 genera; the thorax is long and rectangular, with rows of punc- 

 tures, of which the outer ones are curved; the lateral margin is 

 double, and the prothoracic spiracles are uncovered. " Tlie head 

 is usually equal in size to the thorax, and is narrowed behind 

 into a small neck. The suture of the elytra is imbricated in our 

 genera when the antenme are strongly geniculate. 



The species are found under moss in woods, under stones, and 

 bark. 



Antennae strongly geniculate ; suture imbricated ; middle coxse distant. 2. 

 Antennae feebly geniculate ; suture entire. 5. 



2. Maxillary palpi with last joint subulate. 3. 

 Maxillary palpi with last joint longer. Xantholinus. 



3. Front tarsi not dilated. 4. 

 Front tarsi broadly dilated. Leptolinus. 



* The acetabula are always separated by the mesosternum, which is 

 however, frequently exceedingly narrow; they are continent in Ocypus. 



