330 STAPHTLiNiD^. \_Stenus. 



Male with the seventh segment deeply eniarginate, with an oblong 

 tubercle near the middle of its base ; sixth widely eniarginate with the 

 middle surface depressed and smooth and enclosed by two parallel ridges 

 which are more elevated towards posterior margin, and terminate on each 

 side in a prominent tooth ; the depressed space has a tubercle in the 

 centre ; fifth segment slightly sinuate with a smooth space furnished 

 with a tubercle before sinuation ; fourth segment with a trace of a 

 smooth space and a small tubercle. 



Marshy places ; at roots of grass, in moss, flood refuse, &c. ; common and widely 

 distributed in the Midlands and Southern districts ; rarer in the north ; Scotland 

 rare, Solway and Tweed districts ; Ireland, near Dublin. 



(Section II.) 



This section contains a considerable number of species, which are 

 distinguished by the simple penultimate joint of the tarsi, the absence of 

 spots on the elytra, and by the fact that the hind body is margined ; the 

 colour of the legs is an important character, but in one or two species 

 (e.g. S. prodifor) is somewhat misleading. 



I. Posterior tarsi elongate, as long as, or not much 

 shorter than, tibice, with first joint almost always 

 evidently longer than the last. 

 i. Legs entirely black. 



1. Base of segments 2-5 of hind body without 

 longitudinal keel ; first joint of posterior tarsi 



shorter in proportion to last S. ASPHALTINUS, F. 



2. Base of segments 2-5 of hind body with a short 



longitudinal keel in centre; first joint of pos- 

 terior tarsi longer in proportion to last. 



A. Head almost us broad as elytra. 



a. Form broader, more robust ; male without 

 raised prominence on posterior third of hind 



tibise S. JuNO, J^. 



b. Form narrower ; male with a raised pro- 

 minence on posterior third of hind tibise . S. ATER, Manti. 



B. Head plainly narrower than elytra, scarcely 



broader than thorax S. longitaesis. Thorns. 



ii. Legs more or less light in colour, never entirely 

 black. 



1. Thorax and elytra very coarsely and rugosely 



punctured, with upper surface very uneven . . S. GurNEMEEi, Duv. 



2. Thorax and elytra much less coarsely and more 



regularly punctured, with upper surface not 

 or only slightly uneven. 



A. Tibise dark brown ; size smaller . . . . S. peoditoe, Hr 



B. Tibise more or less reddish or testaceous; 



size larger. 

 a. Elytra as thickly punctured as thorax, 

 which is narrower in proportion, 

 a*. Punctures of elytra distinct, not con- 

 fluent; femora narrowly dark at apex . S. Speoulatoe, Lac. 

 b*. Punctures of elytra confluent ; femora 



broadly dark at apex S. peovidus, Er. 



(v. Rogeri, Kr.). 



