THE FLAT BARK BEETLES. 



563 



Almost 400 species of the family are known, about 60 of which, 

 distributed among 17 genera, are from the United States. These 

 are divided among five subfamilies, four of which are represented 

 in Indiana. 



KEY TO INDIANA SUBFAMILIES OF CTICTJJIBvE. 



a. Front coxal cavities closed behind. 



6. Tarsi not lobed beneath, the fourth joint small ; antenna? with dis- 

 tinct club, their third ioint never longer, usually shorter than the 

 second. Subfamily I. Silvanin.e, p. 561. 



lil). Tarsi with the third joint lobed beneath ; fourth tarsal joint very 

 small: antemne long and slender, filiform; last joint of maxillary 

 palpi in our species large, hatchet-shaped. 



Subfamily IV. Telephanin.f. p. 5G9. 

 aa. Front coxal cavities open behind; antennas usually without club: the 

 third joint longer than second (except in some LmmopMwus) . 

 c. Maxilla? concealed by horny plates which extend out from the sides 

 of the mouth ; thorax as long or longer than broad. 



Subfamily II. Passandrinje, p. 564. 

 cc. Maxilla? not concealed. Subfamily III. Cucu.jin-E. p. 565. 



" Subfamily I. SILVANINAE. 



Elongate, depressed brownish forms, less than 5 mm. in length, 

 having the tarsi 5- jointed in both sexes ; the maxilla? exposed. Three 

 genera occur in the State. 



KEY TO INDIANA GENEEA OF SILVANIN.F. 



a. Club of antennre formed by abrupt enlargement of last three joints; 

 form very slender ; length less than 3 mm. 

 J). The three joints of the club subequal. I. Silvanus. 



hi). The middle joint of the club slightly larger than either of the other 

 two. II. Cathartus. 



aa. Club formed by gradual enlargement of the joints ; form broader; 

 length 3.5-5 mm. III. Nausibius. 



I. Silvaxus Lat. 1807. (L., "pertaining to a wood or forest.") 



Small oblong or elongated species having the head sub quadrate, 

 last joint of palpi obconical; antenna? with joints one and two 

 larger, three to seven smaller, subequal: eighth smallest; nine to 

 eleven forming an abrupt loose club. Elytra with large round 

 punctures arranged in rows. They occur beneath bark, more es- 

 pecially that of oak. elm or poplar, or in grain. Four species are 

 known from the State. 



