COLEOPTERA. 107 



Prothorax much elongated ; punctures separated by at least their own 

 diameters ; pubescence very sparse and inconspicuous. 



S9. » in it ii In s. 

 Prothorax very robust ; punctures very close, never separated by more 

 than one-third of their own width. 

 Third joint of antennae much shorter than the fourth. Alaska. 



90. congener. 

 Third joint of antennae much longer than the fourth. Massachu- 

 setts, Michigan 91. canaliculars. 



Prothorax not canaliculate!. 



Legs pale ; body densely clothed with very long, erect, bristling setae, 



which are very prominent 92. Carolina?. 



Legs black or nearly so ; pubescence short, sub-recumbent, moderately 

 prominent. 

 First joint of posterior tarsi twice as long as the second. ..93. ageilS. 

 First joint distinctly less than twice as long as the second. 



Joints three to five of antennae uniformly decreasing in length. 



94. pndicus. 

 Antennal joints four and five equal in length, abruptly shorter than 

 the third. 

 First joint of posterior tarsi very short, scarcely one-half longer 



than the second 95. minor. 



First joint much more than one-half longer than the second. 

 Form somewhat slender ; head rather large. Massachusetts. 



96. rigiclus. 



Form more robust ; head small. Nebraska 97. incerliis. 



Transverse carinae of abdomen tricuspid ; lateral cusps very small and 



rudimentary 98. parallelllS. 



Transverse carinae not cusped. 



Prothorax very feebly canaliculated ; body depressed, elongated ; species 



rather large. White Mountains, N. H 99. noctiv agtIS. 



Prothorax not canaliculated. 



First joint of posterior tarsi very slightly longer than the second ; punc- 

 tuation extremely fine. California 100. lncilleiitlis. 



First joint of posterior tarsi from one-half to three-fourths longer than 

 the second. 

 Very small species, not exceeding 2.2 mm. in length. 



Elytra much longer than wide, distinctly narrowed toward the base, 



distantly punctured, very highly polished 101. juveiiCUS. 



Elytra nearly quadrate, very densely punctured. 



102. paupercnliis. 

 Larger species, not less than 2.8 mm. in length. 



Antennal joints three to six uniformly decreasing in length ; form 



of body sub-cylindrical 103. liaplllS. 



Antennal joints three and four equal in length; suture of elytra 



but slightly longer than the pronotum 104. enoilis. 



Antennal joints four and five equal in length and distinctly shorter 

 than the third. 



