THE IIISTER BEETLES. 



601 



1142 (3461). Hololepta fossularis Say, Journ. Phil. Acad. Nat. Sci., V, 

 1825, 47 ; ibid. II, 271. 



Resembles closely the preceding, differing only in the 

 striation of the elytra. The first stria is short, extending 

 not over a fourth of the elytra, the second still shorter and 

 the third merely a trace. Males with a deep pit near the, 

 front angles of thorax, this lacking in females. Length 7- 

 9.5 mm. (Fig. 230.) 



Southern half of State; frequent, April 6-June 

 27. Appears to be much more common in spring. Fig 230 x3 

 This and the preceding are very close and time will (0ngl ° aL) _ 

 doubtless prove that they are the same, Say's name having priority. 



Tribe II. HISTRINI. 

 To this tribe belong a number of genera, which live mainly in 

 excrements or beneath bark. They vary much in form and have the 

 mandibles capable of being applied to the front edge of the pro- 

 sternum so as to conceal the mouth. Between the prosternal lobe 

 and the.prosternum proper is a suture, so that the former appears 

 to be a distinct piece. In a number of genera the lobe is very wide, 

 extending to the under edge of the thorax and forming the floor of 

 a cavity which holds the antenna? when the beetle is in repose. 

 "When so extended, the widened portion is called the "pectoral 

 plate." Six of the twelve known genera of the tribe are repre- 

 sented in Indiana, while a seventh probably occurs. 



KEY TO INDIANA GENERA OF HISTRINI. 



a. Antennal cavities beneath the front angles of the thorax, open in front, 

 but closed more or less completely beneath by the pectoral plate. 

 J). Club of antenna? more or less oval, pubescent, and distinctly ringed 

 or annulate ; thorax without a lobe on the side. 

 c. Mandibles rather prominent, upper edge rounded; labrum trape- 

 zoidal ; antennal club broadly oval ; elytra distinctly striate. 



II. HlSTER. 



cc. Mandibles retracted, upper edge acute; labrum short, very trans- 

 verse. 



d. Form ovate; elytra scarcely striate; prosternum broad, the lobe 

 short ; antennal club truncate. HI. Tribalus. 



del. Form more oblong ; elytra distinctly striate ; prosternum of mod- 

 erate width, the lobe distinct ; antennal club rounded. 



IV. Epierus. 



bb. Club of antennas obconical, solid, glabrous; thorax with a distinct 

 lobe on each side ; clypeus truncate. V. Hetjerius. 



aa. Antennal cavities beneath the middle of the mflexed sides of the thorax, 

 in front of the outer portion of the coxa?, not closed beneath by a 

 pectoral plate. 



