156 COLEOPTERA OF NORTH AMERICA. 



Front with clypeal suture distinct ; labrum short, covering 

 the small, not prominent mandibles. 



Prothorax with the side pieces not separate; presternum 

 more or less visible between the coxaj; coxal cavities entire; 

 mesosternum separating the middle coxae; metasternum 

 moderate, side pieces narrow. 



Elytra entirely covering the abdomen. 



Abdomen with live free ventral segments, not remarkably 

 differing in length. 



Anterior coxse conical, prominent, more or less separated; 

 middle ones separate, rounded; posterior coxse transverse, 

 widely separated. 



Legs moderate; tibia3 slender, without terminal spurs; 

 tarsi 3-jointed, the third joint equal in length to the other 

 two, with small simple claws. 



Insects of ver}' small size, found flying: hi twilight, and also 

 under bark and stones; tliey are of graceful form, the elytra 

 being usually wider than the thorax; the species of Bonvouloiria 

 and most Lathridius arc very reniaikably sculptured, with elevated 

 lines on the thorax. 



The genus Monotonia, introduced into this family by many 

 authors, does not belong to it, and will be found in the family 

 Monotomidae. 



We have also excluded from the family Corticat'ia triaignata 

 Mann., which', with Cryptophagus maculatus Mels., must form a 

 new genus, Derodontns; its systematic place is in a new family. 



Our genera are related as follows : — 



Labial palpi 2-joiiited ; antenna^ with outer joints gradually larger; 2. 

 Labial palpi 3-jointed ; antennaj with abrupt 2-jointed club. 



Holoparamecus. 



2. Antennae with 11 distinct joints ; prothorax narrow ; :^. 

 Antennffi with outer joints confused ;* prothorax wide. Bonvouloiria. 



3. Antennae of normal form. •^• 

 Antennae slender, capillary, verticellate with long hairs. Dasycerus. 



4. Prothorax strongly margined ; 2d joint of tarsi not shorter than 



the 1st ; "5. 



Prothorax not, or. very finely marged ; 2d joint of tarsi shorter than 



the 1st. ' • 



.'). Front coxal cavities open behind ; ''• 



Front coxal cavities closed behiud. Stephostethus. 



* Duval describes the antennae of the European species as 9-joiuted; 

 those of the American species appear to have ten joints. 



