PSELAPHIUES. 345 



H. Tarsi with only one claw. 



a. Abdomen with live ventral segments. 



I, Last joint of maxillary palpi oblong-oval or club- 



like. 



1» Antennae placed far apart. 



Maxillary palpi as long as head, last joint oblong-oval ; 

 antennae gradually thickened toward apex ; sides of thorax 

 rounded. Bryaxis, Kug. 



2, Antennae placed near each otlier. 



Maxillary palpi fully twice as long as head, last joint 

 very long, thickened clublike toward apex ; antennae 

 slightly thickened toward apex ; front of forehead pro- 

 duced, with a deep longitudinal furrow in middle ; sides of 

 thorax only slightly rounded. Pselaphus, Herbst. 



II, Last joint of maxillary palpi hatchet-shaped. 



1. Antennae placed near each other. 



Last three joints of antennae large ; front of forehead 

 produced, with a deep longitudinal furrow in middle ; 

 thorax as broad as long, sides rounded in middle, rather 

 more narrowed in front than behind ; elytra with a sutural 

 and abbreviated dorsal stria. Tychus, Leach. 



2, Antennae placed far apart. 



Antennae with first two joints large, two pemdtimate 

 joints transverse ; forehead produced in front, with two 

 impressions between eyes and often a longitudinal furrow ; 

 thorax about as broad as long, sides rounded in middle, a 

 fine curved impressed line before base ; elytra punctured, 

 with a sutural and abbreviated dorsal stria. 



Bythinus, Leach. 



/>. Abdomen with six ventral segments. 



X. Antennae longer than head, middle joints about as 

 broad as long. 



Last joint of maxillary palju pointed oval ; thorax about 

 as long as broad, sides dilated before middle, usually with 

 three depressions before base, united by a transverse im- 

 pression ; elytra with a sutural and ablireviated dorsal 

 stria. Body flat. Bvjjlectus, Leach. 



II» Antennae not much longer than liead, middle 

 joints transverse. 



