102 COLEOPTERA OF NORTH AMERICA. 



anteniiiB are more or less geniculatecl, 11-jointed, and are inserted 

 under the lateral margin of the front; the first joint of the max- 

 illary palpi is short. 



We would arrange our genera in four groups, as follows : — 



Middle coxae at the sides of the breast. Oxypoki. 

 Middle coxae contiguous, or nearly so; 



Abdomen not margined. Osorii. 

 Abdomen margined. 



Antennae 11-jointed. Oxvteli. 



Antennae 10-jointed, eyes very large. Megalopes. 



Group I. — Megalopes. 



This group contains but a single genus, Megalops, having the 

 eyes larger than in Stenus, and the thorax coarsely, irregularly 

 punctured, and marked with a few lateral transverse furrows. The 

 antennce are inserted under the lateral margin of the front, and 

 have but ten joints; the tarsi are 5-jointed. 



Two species are known to us from the Atlantic district; they 

 are found under the bark of trees, and are very rare. 



Group II. — Oxypori. 



But a single genus is known, Oxyporus, found in fungi. The 

 head is very large, with the eyes small, not prominent, the man- 

 dibles long and decussating, not dentate; the mentum is armed 

 ,with a medial bifid tooth ; the last joint of the labial palpi is 

 lunate ; the middle coxaj are very widely separated, and the tarsi 

 are 5-jointed. The abdomen is strongly margined. 



Group III. — Osorii. 



The body is cylindrical, the middle coxae are contiguous, the 

 tarsi are 5-jointed, and the abdomen is not at all margined. The 

 ligula is corneous. The mandibles are stout, but not toothed. 



The genus Osorius is distinguished from Holotrochus by the 

 front tibiae being armed with spines. Both occur in the x\tlantic 

 region. 



Group IV. — Oxyteli. 



The body is either cylindrical or depressed, and the abdomen is 

 strongly margined ; the middle coxae are contiguous, or nearly so ; 



