76 COLEOPTERA OF NORTH AMERICA. 



A. Antennal cavities on the anterior part of the presternum ; (all the tarsi 



have two claws in our genera) ; 



Antennae inserted under the margin of the front ; mandibles promi- 

 nent ; 2 



Antenna? inserted upon the front ; mandibles retracted ; 4 



2 Mesosternum emarginate, rarely truncate ; club of antennae round, 



annulated. Hister. 



Mesosternum slightly prominent at the middle, received by the pro- 

 sternum ; 3 



3 Club of antennae round, annulated. Phelister. 

 Club of antennae obconical, truncate, solid. Hetjerius. 



4 Antennal cavities under the angle of the thorax ; club round, annu- 



lated ; 5 



Antennal cavities at the angle of the thorax itself; club of antennae 



annulated, truncate. Tribalus. 



5 Pygidiuni inflexed, thorax and elytra costate, prosternal lobe obsolete. 



Onthophilus. 

 Pygidiuni defiexed, elytra striate. Epierus. 



B. Antennal cavities at the middle of the inflexed portion of the prothorax, 



near the sides. 

 Mesosternum emarginate, receiving the base of the presternum ; 3 

 Mesosternum truncate, slightly prominent at the middle, received by 



the presternum ; 2 



2 Prosternal lobe short, broad ; pygidium inflexed ; body globular. 



Bacanius. 

 Prosternal lobe long, rounded ; pygidium vertical ; body globular, 

 margined. Sph^roderma. 



3 Posterior tibiae broad ; anterior tibiae with a small terminal spur ; body 



oval, convex. Dendrophilus. 



Posterior tibiae narrow ; anterior tibiae with a very large terminal 



spur ; body oblong, sometimes depressed. Paromalus. 



To Sphseroderma must be referred Bacanius marginatus Lee* 

 The occurrence of the genus here is remarkable, as the only other 

 species is found in Madagascar. The genus Hister, as above 

 defined, includes all the divisions of my scheme in Proc. Acad. 

 Nat. Sci., vi. 39, except 12 and 13, which form Phelister, regard- 

 ing the generic value of which group I still entertain some doubts. 

 Hister corticalis Lee, placed by me in division 12, has been very 

 properly removed by De Marseul to Carcinops, a division of Pa- 

 romalus. Hister, as above defined, contains several of the genera 

 adopted by De Marseul, which are separated by the following 

 characters : — 



Anterior tibiae with the tarsal groove well defined, often sinuate ; (a single 

 range of small spines on the middle and posterior tibiae) ; 



* Proc. Acad. Nat. Sci. Philad., vi. 292. 



