748 FAMILY XXXVII. — ELATERIDiE. 



d. (;;iypeus flat or slightly concave; thorax slightly wider at middle 

 than elytra, strongly narrowed in front; length 14-17 mm. 



1415. FISSILIS. 



dd. Clypeus strongly concave; thorax not wider at middle than elytra; 

 length 15-17 mm. 1416. canadensis. 



(III. Hind angles of thorax with but one carina. 



e. Fourth joint of antennae at least one-third longer than third. 

 /. Size larger, 12.5 or more mm. ; form rather robust, 

 fir. Surface of thorax sparsely and rather finely punctate, the sides 

 straight from base to near apex ; clypeus subangulate at apex ; 

 length 12.5-14 mm. 1417. sagittaeius. 



gg. Surface of thorax, at least on sides, coarsely and rather densely 

 punctured ; sides more or less rounded toward apex ; clypeus 

 broadly rounded ; elytral intervals coarsely and distinctly punc- 

 tate; length 14-15 mm. 1418. difficilis. 

 ft. Size smaller, not over 12 mm. ; form usually much more slender. 

 h. Thorax very finely and so densely punctate as to make the sur- 

 face dull; pubescence short, erect; length 10-11 mm. 



OPACICOLLIS. 



7(/(. Thorax normally punctate, the punctures' either much more 

 sparse or much coarser. 

 /. Surface closely pubescent with long gray prostrate hairs; ely- 

 tra but slightly narrowed from base to apex ; length 10- 

 11.5 mm. 1419. pilosus. 



a. Surface sparsely pubescent with much shorter hairs; elytra 

 (except in macer) distinctly narrowed behind the middle. 

 j. Carinse of hind angles very long, and close to margin ; third 

 .I'olnt of antennfe one-half longer than second, the two to- 

 gether slightly shorter than fourth ; length 11 mm. 



1420. CABIN L'S. 



jj. Carinaj of hind angles not reaching middle of thorax; third 

 joint more than one-half longer than second. 

 7c. Length not more than 9 mm. ; form very slender. 



I. Clypeus rounded in front, convex ; thorax short, not 



longer than wide. 1421. tkapezoideus. 



77. Clypeus subtruncate, concave; thorax more slender, 



longer than wide. 1422. pkasinus! 



Ick. Length 10-12 mm. ; form more robust. 



m. Clypeus strongly concave; sides of thorax straight; ely- 

 tra parallel or nearly so. 142:;. macek 

 mm. Clypeus flnl „v subconvex; sides of thorax more or less 

 rounded; elylra distinctly narrowing behind the mid- 

 dle. 



/'. Dark reddish-brown or fuscous; disk of thorax coarse- 

 ly and rather sparsely punctate. 



„ , 1424. verberans. 



nn. Pale reddish-brown; disk of thorax very finely and 

 more sparsely punctate. I42ri. anoustatus 



(f. Fourth joint of anteimie but little, if any, loug«r than third 



