with more or less distinct sublateral yellow spot or vitta behind the 

 middle; hind tibiae without row of punctures along inner margin 

 (except amplus) ; size moderate to large 5 



Prosternal process rather broad and only moderately convex, less 

 broadly expanded than in the preceding species and never with di- 

 lated side margins, its tip sharply acuminate (except hypomelas) ; 

 elytral reticulation well impressed (less conspicuously so in hypo- 

 mehs), hind tibiae with a row of punctures along inner margin; 

 species of moderate to large size, deep black (except hypomelas.) 9 



Prosternal process narrower, varying from moderately convex to an- 

 gularly or acutely carinate (except arcticus, in which the prosternum 

 is virtually flat) '. 11 



5. Prosternal process with the sides more broadly margined just behind 

 the coxae; elytra with sublateral yellow vitta behind the middle (ex- 

 cept amplus) ; minute punctules of the elytra occurring on the reticu- 

 lating lines 6 



Prosternal process with side margins not dilated behind the coxae ; 

 elytra with postmedian and subapical sublateral small yellow spots of 

 variable distinctness ; minute punctules of the elytra occurring within 



the areolae 8 



6. Protarsi of male only narrowly dilated, the basal joint with only a 

 small apical area clothed with glandular pubescence* anterior protarsal 



claw of male with ante-basal tooth. (Ontario to Arizona.) semivittatus 



Protarsi of male very distinctly widened, the basal joint clothed be- 

 neath with glandular pubescence in fully the apical half 7 



7. Meshes of elytral reticulation very small and subequal, either through- 

 out or excepting only a narrow baso-sutural area ; anterior protarsal 

 claw of male with a large angulate basal lobe, the posterior claw 



broader but not lobed at base (Florida.) johannis 



Meshes of elytral reticulation irregular in form and more or less un- 

 equal almost or quite throughout. 



Anterior protarsal claw of male with a strong rectangular basal 

 dilatation ; hind tibiae without a row of punctures along the inner 



margin (Pennsylvania; North Carolina.) stagninus 



Anterior protarsal claw of male arcuately thickened post-medial- 

 ly; elytra with a small sublateral yellow spot behind the middle; 

 hind tibiae with a series of four to six punctures along the inner 

 margin. Length 11.5 mm. (Kentucky; Missouri.) amplus 



8. Side margins of thorax rather narrow. (Canada and Northeastern 



States.) . obtusatus 



Side margins of prothorax notably broad. (Massachusetts; Long 

 Island.) planatus 



9. Fine punctures of the elytra occurring at the intersections of the retic- 

 ulations; metasternal groove unusually short; color piceous with 



brownish margins. (Alaska to Vancouver.) hypomelas 



Fine punctures of the elytra very minute and occurring within the 

 meshes of the reticulation ; metasternal groove well developed ; color 

 black, side margins not paler 10 



