18 larvtE of the peionin^. 



cylindric, with distinct supplementary joint. Palpi short, conical; 

 last joint of maxillary one-half length of last joint of labial, very 

 short, conical. Postcondylar carina acute, projecting. Subfossal 

 process short, triangularly acute. 



Posterior area of pronotum slightly rugose. Eusternal area of pro- 

 thorax distinct. 



Pleural discs as in Ergates. Spiracles narrowly oval, small. Anal 

 lobes rugose, dorsal lobe prominently projecting. Form robust, 

 cylindric, scarcely tapering. Texture leathery, finely rugose. 



Range: Mountains of Virginia and Pennsylvania, northward 

 through Canada and the western United States. Confined to the 

 higher elevations. 



The work and habits of this larva are similar to those of Ergates^ 

 though it is confined to sapwood and decaying wood. 



Prionus Geoff. 



Head robust, trapezoidal, widest behind; front projecting over 

 epistoma in a dull transverse carina; mandibles robust, upper inner 

 face not striate; lab rum transverse; ocelli absent; last joint of 

 antennae with a small lobe on truncate tip; palpi conical. Eusternum 

 distinctly separated by curved suture from presternum. Pleural 

 discs distinct on six abdominal segments, radially striate; form 

 tapering to last segments; texture tough, shining. 



Four species have been reared from this genus. As larvae they are 

 separable with difficulty, the distinctions lying chiefly in the labrum 

 and palpal joints. The series studied under each species is rather 

 limited, and some of the described characters may be variable. This 

 is a genus of much economic importance. 



Prionus imbricornis L. 



Epistoma projecting in a dull dentate carina over clypeus, distal 

 extremities and two median teeth largest; front produced in a straight 

 transverse carina, rather sharp edged, divided in middle; mandibles 

 from side subtrapezoidal, robust, short, outer face rugose, cutting 

 edge obliquely truncate, upper inner angle produced in a short obtuse 

 tooth, not striate. Labrum transversely oval, not twice as wide as 

 long, densely hairy, the hairs extending from anterior edge to beyond 

 middle. Ocelli absent. Antennae short, thick, last joint slightly 

 longer than thick, bearing a small supplementary joint. Palpi short, 

 conical, last joint of maxillary palpi cylindric, as long as or longer 

 than second is wide, hairs on lacinia and ligula so dense that integu- 

 ment can not be seen through them. Postcondylar carina distinct; 

 subfossal spine acute conical. 



Posterior area of pro thorax not strongly rugose; eusternal area dis- 

 tinct; legs very hairy, last two joints (not spine) subequal; pleural 

 disks very prominent on first six abdominal segments; an orbicular 



