AMERICAN COLEOPTERA. 237 



are no other characters excepting size, the last mentioned form being 

 the smallest, and as we find all grades of size in body and mandible 

 tooth, I prefer uniting them. 



This species is distributed along the Atlantic and Gulf coasts from 

 the Middle States to Texas, and becomes smaller as it approaches the 

 latter locality. 



Group viarginata. 



This group contains two maritime species, and has the following 

 characteristics. 



Thorax scarcely differing in the sexes, elytra differing in shape. 

 Right mandible S , toothed beneath. Last joint of maxillary palpi 

 slightly longer than the preceding. Hind trochanters red. Claws 

 long and slender. Third and fourth segments of abdomen moder- 

 ately prolonged. 



Elytra with median basal spot, humeral lunula oblique but straight, 

 hooked at tip. 



The presence of the mandibular tooth in the male, and the retrac- 

 tion of the suture of the female, seem to me worthy of use as group 

 characters. 



The two species differ, especially as indicated by pi. I, fig. 19, 

 {hatjiafa), and 20, (niarginata) . 



C. hamata, Brulle. 



Male. — Feeble mandibular tooth. Elytra! apex rounded. 



Female. — Suture retracted, and with an emargination and a spiniform pro- 

 longation of the inflexed portion. 



C niarginata. Fab. 



Jfa/e.— Moderate mandibular tooth. Apex of elytra yith slight sinuation 

 near the suture, which is acutely but feebly prolonged. 



Female. — Suture retracted, and with a slight emargination and the inflexed 

 portion squarely truncate. 



Group cuprascens. 



The only defining character of this group is the presence of a 

 sinuation, and often a tooth on the female elytron one-fourth from 

 the tip. 



The elytra in the two sexes do not vary to any marked extent in 

 form. The mandibles are not toothed in the male. The thorax is 

 similar in the sexes, very slightly more impressed in the female, the 

 trochanters red, claws long and slender, and with abdominal segments 

 feebly prolonged. 



