148 ACADEMY OF NATURAL SCIENCES 



Length nearly three-fifths of an inch. 



Several specimens of this interesting insect occurred under 

 dried bison dung near the Rocky [251] Mountains. They were 

 generally pruinose, or more or less covered with a whitish powder. 

 [n form they agree perfectly with the present genus, but the 

 meutum is rather too narrow, and the terminal joint of the palpi 

 is rather too much dilated to correspond perfectly with Mr. La- 

 treille's character of the genus. 



[Belongs to Uusattus Lee. ; a genus closely allied to Praocis 

 Esch.— Lec] 



PLMELIA Lat. 



P. ROTUNDA. — Black, with a few white hairs; anterior thora- 

 cic angles prominent, acute. 



Inhabits Ark ansa. 



Body rounded, black, immaculate, with numerous white hairs 

 arising from excavated punctures : head, anterior termination 

 truncate, and much narrowed by the concavity of the latei-al edge; 

 over the insertion of the antenna), a prominent acute angle : an- 

 tenna} blackish-piceous; second, fourth, fifth, and sixth joints, 

 equal ; third slightly longer, obconic-cylindric ; remaining joints 

 more ovate, two or three terminal ones rather larger, the last 

 acute at tip: palpi dark piceous, terminal joint truncate at tip: 

 thorax very short and wide; anterior angles prominent, acute ; 

 punctures of the lateral margin much dilated, excavated, con- 

 fluent ; those of the disk smaller and distinct ; lateral edge rec- 

 tilinear : elytra with profound, excavated punctures at base, and 

 .-smaller and less indented ones towards the tip. [252] 



Length less than one-fourth of an inch. 



This species we observed only within the distance of a hundred 

 miles from the Rocky Mountains. In the form of the body it 

 very closely resembles Olivier's figure of his /'. ivjfafa, the P. 

 tkmroUis of Fabricius. This new species I believe to be the 

 1irst of this genus that has yet been found on this continent. 

 The mentum is proportionally much larger than that of P. btpunc- 

 tata, entirely concealing the mandibles even when viewed latei-al- 

 ly, afiFording space only for a circumscribed play of the palji. 

 But the antennic difl'er from those of the bipunctata, which have 

 ihe terminal joint smaller and shorter than the preceding, and 



[Vol. III. 



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