The only British species of the genus Oodes is easily distinguished from 

 an Amara, which it superficially resembles, by it having the thorax quite 

 smooth, the colour dull black, and the elytra parallel-sided. 



In the part of Amara included in Sub -section I, the thorax is rounded at 

 the sides and narrowed in front, with distinct impressions in the posterior 

 angles; the colours are bronze or brassy black (rarely quite black). The 

 insects are oval in outline, with short legs. 



The genus Calathus is easily recognised by the elongate-oval outline, the 

 nearly square thorax, the black or red colours (never coppery or brassy), and 

 the long slender legs of the species. The hinder tarsi are marked with a 

 distinct groove, which runs along the whole length of the upper surface, pass- 

 ing from joint to joint. 



II.— Thorax narrower at the base than the elytra : 



1. — Elytra brilliant green, or green with a yellow border ; or bright cop- 

 pery ; or black with long yellow hairs. 



Elytra hairy and rough - - Chlce?iius. 

 Elytra smooth and hairless. 



Posterior angles of the thorax rounded - - Anc/wmenus (part.) 

 Posterior angles of the thorax distinct - - Pterostichus (part.) 



2. — Elytra blue-black - - Pristonyclms. 



3. — Elytra bronze or greenish bronze - - Aiichomenus (part), Olis- 



thopus and A7nara (part.) 

 In A mara the posterior angles of the thorax are more or less distinct ; in 

 this group of the genus Anchomenus and in Olistlwpus they are rounded. 

 The points of difference between the latter will be given afterwards. 



4. — Elytra red at base and blue or green at apex - - Anchomenus 



prasinus. 



5. — Elytra dark or reddish. 



a. — -About one inch in length ; the elytra with indistinct striae 

 Sphodrus. 



bs — Under § inch in length, or if longer, with distinct striae. 



1, — Anterior tibiae slender, scarcely thickened at the apex - Cala- 

 thus piceus ; Taphria ; and part of Anchomenus. 



Calathus piceus is easily distinguished by the furrow on the upper surface 

 of the hinder tarsi. Taphria has the terminal joint of the labial palpus dis- 

 tinctly triangular or hatchet-shaped. Anchomenus has the terminal joint of 

 the palpi cylindrical, and the hinder tarsi not grooved. 



2. — Anterior tibiae thickened very distinctly at the apex - S to mis, 

 Platyderus, PterosticJius (part), and Amara (part.) 



Stomis is at once recognised by its long, very prominent mandibles, 



