BY THOMAS G. SLOANE. 463 



e. Prothorax with posterior angles prominent, almost rect- 

 angular; the base truncate. C. rectangidare group. 



ee. Prothorax with posterior angles rounded off. 



/. Frontal sulci short, subparallel. C, disjjar group. 



ff. Frontal sulci diverging strongly backwards. 



g. Two supra-orbital punctures near each eye ; prothorax 

 with marginal channel tripunctate. C. campestre group. 



gg. One supra-orbital puncture near each eye ; prothorax 

 with marginal channel bipunctate. C. hahitans group. 



dd. Anterior tibiae bidentate; the inferior ridge, when viewed 

 from below, almost parallel with exterior ridge and not 

 extending forward past upper large external tooth. The 

 apical part of the lower side of anterior tibiae forming a 

 broad apical plate. G. marginatum group. 



II. Suborbital channel to receive antennae wide, divided longitu- 

 dinally in middle by an oblique ridge, lower part of channel 

 dividing the gense from the guise. Penultimate joint of 

 labial palpi short, thick. Elytra quadri-punctate. Anterior 

 tibiae bidentate. 

 h. Inflexed margin of elytra not narrow behind first ventral 

 segment. C. interrwptum group. 



M. Inflexed margin of elytra narrow behind first ventral 



segment. 

 ^. Frontal sulci not diverging backwards to define the space 

 between them and the eyes. C. scaritioiJes group. 



a. Frontal sulci diverging backwards and defining posterior 



margin of the s})ace between them and the eyes. 

 k. The space betweeen the frontal sulci having its base 

 rounded and not filling all the interval between their 

 posterior extremities. C. honellii group. 



kk. The space between the frontal sulci having its base trun- 

 cate and filling all the interval between their posterior 

 extremities. C. ^.-punctatum group. 



