CARABIDAE. 25 



Group II. — Pericalli. 



These are distinguished from genuine Lebire by the larger size 

 of the labrum, which covers in great part or entirely the mandibles. 

 The palpi are slender, and the tarsi filiform. Two genera are 

 found in the Atlantic district: — 



Head constricted behind, thorax pedunculate. Rhombodera. 



Head not constricted behind, thorax truncate. Coptodera. 



The mentum is toothed in both; in the second genus the ungues 

 are serrate, in the first they have only a basal dilatation. 

 Didetus Lee. is synonymous with Rhombodera. 



Tribe VIII.— PTEROSTICHI1VI. 



Ligula free at the extremity, with distinct paraglossa? (except in 

 one foreign genus); antennae with three glabrous basal joints, the 

 apex of the third rarely pubescent in foreign species. Head not 

 contracted into a neck, though sometimes narrowed behind. Elytra 

 obliquely sinuate at the apex, never truncate; the basal margin is 

 distinct in all of our species, and forms an angle at the humeri. 

 Anterior tibiae either slender and scarcely spinous, or thickened 

 and spinous at tip; anterior tarsi of the male with three dilated 

 joints furnished beneath with squamiform papillae. 



Schaum includes in this tribe genera having the third joint of 

 the antenna? partly pubescent, and less than three joints of the 

 anterior tarsi of the male dilated (as Stenomorphus, Patrobus, &c). 

 By admitting these, however, it becomes impossible to fix distinct 

 limits to the tribe, and I have therefore removed these heterogene- 

 ous elements to form other tribes, to be found below. According 

 to the form of the anterior tibiae, two groups may be formed of 

 our genera: — 



Anterior tibiae slender, dilated joints of the tarsi narrow. Plattni. 



Anterior tibiae thickened at the extremity, dilated joints of the tarsi tri- 

 angular or cordate. Pterostichi. 



Group I. — Platyni. 



By the slender form of the antenna? and legs this group osculates 

 with the last members of the first group of Lebiini. And this 

 resemblance is further increased by the occurrence of serrate un- 

 gues in some members of the present group. 



