45 



the species and by the legs being stout, whilst in these two genera they 

 are slender. It may be distinguished from the other three genera of the 

 family by the characters given above. The British species number about 

 thirty. They vary considerably in size, but are generally easily recognised 

 by their compact form and by the intermediate tarsi of the males being 

 widely dilated — these joints not being furnished with the long hairs which 

 form a sole to the feet of Dichirotrichus, Anisodactylus, and Biachromus, 

 The arrangement I have followed is nearly that given in Cox's " Manual/' 

 being, I believe the simplest manner of separating the species. They 

 are divisable at once into two groups, the first comprising those which 

 have the upper side more or less thickly punctured and the elytra pubescent ; 

 the second containing those which are destitute of regular punctuation (ex- 

 cept occasionally the outer interstices), and where pubescence is wanting. 



Geoup I. — Interstices of the elytra punctured and hairy (head and thorax 

 generally punctured.) 



1. Head, thorax, and elytra greenish or bluish : — 



Length \ inch ; posterior angles of the thorax rounded ; colour dull 



- - obscurus. 



Length \ inch ; posterior angles of the thorax rounded ; colour bright 



- - azureus. 



Length about 4 lines ; posterior angles of the thorax right angles 



- - punclatulus, 



2. Head and thorax pitchy ; elytra dull green : — 



Posterior angles of the thorax pointed ; length J inch - sabulicola. 

 Posterior angles of the thorax rounded; length J inch; sides of 

 thorax much rounded - rolundicollis. 



3. Head, thorax, and elytra pitchy or black :— 



a. Length under 5 lines. 



Thorax nearly square and with the sides much rounded in front - - 



rupicola, puncticollis. 



These species resemble one another very closely, and are with difficulty 

 distinguishable from description. Rupicola is broader and longer and has a 

 duller appearance than puncticollis, which has a more shiny appearance, and 

 measures from 3 to 3| lines. 



Thorax much wider than long with the sides rounded in front. Punc- 

 tuation not so distinct as in the two previous species. Length 

 3 J lines - rufibarbis {ruHlabris.) 



Thorax with the sides not rounded in front; length 2 J to 3 lines 



- - parallelus. 



