IlnHplvii.'] AnEPiiAGA. 155 



on the elytra are closer, smaller, and innre frequent in each stria ; from 

 //. rvjicoUii< it differs by the absence of striae at the base of the thorax, 

 and by having the apex of the elytra more rounded than in that species ; 

 from H. varirgahis it may be at once separated by its lighter colour and 

 li'Rs pronounced dark markings, the less coarse sculi)ture of the elytra,- 

 and the much more prominent shoulders, the angle formed by the sides 

 of the elytra and thorax viewed sideways being much more pronounced ; 

 the first punctures (at -base) of the first five rows on the elytra are as a 

 rule much stronger than the others. L. 3-i- mm. 



Ponds and ditches; not common; Lee, Earlswood, Peckhani, Tottenham, Eslior; 

 Kingsbury ; Sohani, Cambridfrc ; Swaftliam ; Knowle, near Birmingham ; Eggington 

 and Repton, near I5urton-oii-Trent ; Weston-super-Mare; Askham, York; Nortlinni- 

 berlaud district, not common (Ouseburn, Ileaton, Gosforth, &c.) ; Ireland, near Belfast; 

 not recorded from Scotland. 



H. ruficollis, De O. Ovate, ferruginous ; head with base dark, 

 diffusely jmnctured ; thorax with anterior margin more or less dark, 

 short, strongly contracted in front, rather diffusely punctured, more 

 strongly at base, centre of disc smooth with a trace of a central furrow 

 usually indicated ; base with a plain longitudinal stria on each side ; 

 elytra at base broader than base of thorax, with the shoulders -widened, 

 strongly contracted to apex, with rows of ratlier strong striae set in black 

 lines which in })laces are confluent and form dark spots. L. 2| mm. 



Ponds and ditches; occasionally in running streams; abundant throughout the 

 kingdom ; not recorded, however, us yet, from the extreme north of Scotland. 



H. fluviatilis, Aube. This species comes near H. riifiroUis but is 

 lighter in coloui', and the lines of the elytra although stronger in places 

 and apparently forming spots are never confluent ; it is also much narrower 

 at the shoulders, and the elytra are less acvmiinate at apex, so that it appears 

 more parallel-sided : these differences are rather hard to explain, but 

 will at once be seen by comparing the two species. L. 2 1 mm. 



Running streams, and not found in stagnant water like the preceding; usually 

 considered common, but it is very often confounded with ruJicoUis in collections': 

 London district, apparently rare, Wimbledon, Micklehani, Eslier ; widely distributed, 

 but in all probability much less common than it is supposed to be in many districts ; 

 Scotland, very rare, in clear slowly moving water. Forth district (Muttonhole, Edin- 

 burgh, D. S.); Ireland, Armagh. 



H. striatus, Sharp. " Kipial in size to the small varieties of 

 II. riificoUis, which it resembles in colour, but from which it may be 

 distinguished by being much narrower at the shoulders, and by the 

 black lines on the elytra showing no temlency to being dilated at any 

 places into spots; also closely allied to //. Jfnviafi/i.-^, but to be distin- 

 guished from that species by its smaller siza and darker colour, and l>y 

 the black lines on the elytra being throughout of ev(>n width, whereas 

 in iluviatills those lines are sub-inteiriipled at places" (!■',. M. M. vi. 81). 

 L. '2% mm. 



Found by Dr. Sharp in great numbers in a pond on the banks of the Xith, alxmt 



