558 



FAMILY XX.- — RHYSSODIDiE. 



antennae, usually received in a cavity at the apical angle of the tho- 

 rax, and the widely separated coxa 1 . Five genera are recognized by 

 Casey.* While no member of the tribe has as yet been noted from 

 Indiana, two of the genera, each of which contains a single species, 

 may be represented in the State. 



KEY TO INDIANA GENERA OF MURMIDIINI. 



a. Antennal cavities visible from above; prosternal lobe large, completely 

 concealing the labrnm and month parts in repose ; legs strongly re- 

 tractile. Murmiditjs. 

 aa, Antennal cavities visible in front, but not from above ; prosternal lobe 

 truncate, not concealing the mouth parts ; legs free. Mychocerus. 



Murmidius ovalis Beck., brownish, shining, elytra with rows of 

 distant pnnctnres, length 1.3 mm., is widely dispersed by commerce. 



Mychocerus depressvs Lee, reddish-brown, depressed, length 1 

 mm., is a rare southern species which has been taken near Cincin- 

 nati. 



Family XX. RIIYSSODIDiE. 



The Wrinkled Bark Beetles. 



This family comprises only four North American species, two 

 from each side of the continent. The name of the family is founded 

 upon that of the typical genns Rhyssodes, meaning "wrinkled- 

 form, ' ' and doubtless refers to the deep grooves of head and thorax. 

 They are narrow, elongate, somewhat flattened brown beetles having 

 the head strongly constricted behind into a neck, and furrowed by 

 two deep grooves; antenna? composed of 11 nearly equal rounded 

 joints (Fig. 4, No. 12), inserted under the frontal margin; thorax 

 long, deeply grooved; scutellum wanting; elytra rounded at tip, 

 covering the abdomen ; front coxal cavities widely separated, closed 

 behind; abdomen with six ventral segments, the first broadly trian- 

 gular, widely separating the coxae ; legs short, the front tibiae ter- 

 minated by two hooks; tarsi 5-jointed, very slightly pubescent be- 

 neath. 



The principal paper treating of the family is the following: 



LeConte. — "Notes on the Rhyssodidae of the U. S.," in Trans. 

 Amer. Ent. Soc, V, 1875, 162-168. 



The two~ species of the Atlantic slope both occur in Indiana, 

 living under bark of decaying logs. They belong to different 

 genera, separated as follows : 



*Ann. N. Y. Acad. Sci., VIII, 1895, 451. 



