18 ADEPHAGA. 



half of the suture. The presternum is sparingly and coarsely 

 punctured, grooved down the middle of the front half, flat behind, 

 L. 2^ mm. 



Merton, Surrey; Cambridge (Sharp); Isle of Sheppey (J 

 J. Walker). 



H. heydeni, Wehncke, Deutsch Ent. Zeits. 1875, 122 (Edwards, 

 I.e. p. 8). Smaller than H. ruficoUis, comparatively wider at the 

 shoulders and more abruptly narrowed behind ; the interstices of the 

 elytra are without punctuation in the female, whereas in the last- 

 named species they are punctate throughout. L. 2\ mm. 



Locally common ; Hampstead ; Lee ; Brighton District ; New 

 Forest ; Stony Stratford ; Leicester ; Hornsey ; Cotswold District 

 (abundant in ponds). 



H. wehnckei, Gerh. Deutsch Ent. Zeits. 3 877, 448 (Edwards, 

 l.c. 9) ; H. imtiiaculatus, Newbery {nee Gerh.), Ent. Mo, Mag. 

 xliii. (2 Sei'. xviii.) 1907, 4. The characters of this species are given 

 fully in the table ; specimens which are not fully coloured might be 

 mistaken for H. fluviatilis, L. 2| mm. 



Bury St. Edmunds ; Cotswold district (very common in mill ponds); 

 Whitwell Common, Felthorpe and Brundall (Norfolk); Mallow, 

 Ireland (Mitford). 



H. immaculatus, Gerh. {nee Newbery), Zeit. fiir. Ent., Nouv. 

 Ser., vi. p. o6, Breslau, 1877 (Edwards, l.c. 9). This species is closely 

 allied to the preceding ; the females are easily distinguished by the 

 punctuation of the elytral interstices as desciibed in the table ; the 

 males can only be known with certainty by reference to the genitalia, 

 but Mr. Edwards has noticed that there is a tendency in this species 

 for the elytral punctures forming the apex of the ninth row to become 

 merged in a black marking, this tendency being apparently absent in 

 H, ivehnekei. L. 2|- mm, 



Lee, Kent ; Sandown, Isle of Wight ; Norwich ; Deal ; Isle of 

 Sheppey ; Colwall ; Braunton ; Stony Stratford ; Campeltown. 



DYTISCID^. 



HYDROPORUS, Clairville. 



H. hop£Fgarteni, Schilsky, Deutsch Ent. Zeitsch. 1892, 193. 

 Elongate oval, sub-depressed, head and thorax dark, the margins of the 

 latter somewhat lighter, elytra dark or pitchy-brown with traces of 

 lighter colour towards base near the shoulders ; these, however, are 

 probably variable, and are more or less obscure; superficially the elytra 

 appear unicolorous; head extremely finely sculptured, thorax with 

 very diffuse fine punctures, the interspaces being very finely aluta- 

 ceous ; elytra moderately closely and distinctly punctured, rather 

 strongly alutaceous ; antennae dark, with lighter base ; legs pitchy. 

 L, 2^ mm. 



Not uncommon in March in the ditches behind the sandhills at 



