186 ADEPiiAGA. [Ili/droporus. 



Ponds, &c. ; one of the commonest of the Dytiseida? not only in Britain, but also 

 throughout Europe, extending from Finland to Algeria, and from Britain to Northern 

 Persia ; the thick pubescence and fine punctuation at once distinguish it from I£. 

 nigrita ; the elytra also are longer in proportion ; from H. discretus it may be 

 separated by its shape, thicker pubescence, and lighter base of elytra. 



K. planus, F. Oval, not very convex, very plainly pubescent, 

 thickly and finely punctured, head and thorax black, elytra fuscous with 

 the base and shoulders more or less obscurely testaceous, legs reddish, 

 antennae fuscous with red base ; last segment of abdomen pubescent with 

 the apical half thickly punctured ; male with the front tarsi broader than 

 in female. Long. 4-4|, lat. 2-2-^ mm. 



Ponds, &c. ; one of the commonest species throughout the kingdom ; it varies some- 

 what in colour and also in size; it is most closely allied to the preceding, from which 

 it may always be distinguished in doubtful cases by the larger third joint of the front 

 tarsi and the sculpture of the apical ventral segment. 



H. lituratus, F. (xanihnpus, Steph.). Oval, rather convex, 

 shining, plainly l)ut rather scantily pubescent, distinctly but rather finely 

 punctured, head and thorax black, the latter less evidently punctured on 

 disc than on margins ; antennae and legs testaceous, the former fuscous 

 towards apex ; elytra fuscous or brownish, with the margins and base 

 more or less broadly and distinctly testaceous ; last abdominal segment 

 indistinctly punctured ; the colour, sculpture, and pubescence are some- 

 what variable; the sexes are hard to distinguish. Long. 3|, lat. 2 mm. 



Stagnant ponds, especially in woods ; not uncommon and widely distributed from 

 south to north ; Scotland, local, Lowlands, Tweed, Forth, Sol way ; Ireland, 

 Armagh (?). 



££. marg-inatus, Duft. This species in form and general appear- 

 ance rather closely resembles H. planus, but is somewhat larger and 

 broader, and may at once be distinguished by its reddish head (which is 

 lighter in front and beliind), broadly testaceous margins of thorax, and 

 extremely dense and fine pubescence and punctuation ; the elytra are 

 variable in colour, being usually fuscous or fuscous-brown with the sides, 

 apex, and base more or less broadly testaceous ; in some specimens the 

 testaceous colour prevails ; legs red, antennae fuscous with red base ; 

 itnderside black ; male with the anterior tarsi considerably broader than 

 in the female : the species may at once be distinguished by its sculpture. 

 Long. 4|, lat. 2| mm, 



Punds, &c.; one of our rarest Dytiscidse, althou2;h there seems no reason why it 

 sliould not be found in greater numbers ; in fact it is probable that it is occasionally 

 piissed over in mistake for planus ; Twyford and Eggiugton, near Repton, Burton-on- 

 Trent (W. Garneys, who at th(^ time did nor recognize it, or might have secured more) ; 

 Marlborough (Hart Smith) ; Knowle, near Birmingham, and Cannock Chase (Blatch); 

 first taken in Britain by Hamlet Clark at Woburn, Bedtbrdshire. 



H. ferrug'ineus, Steph. (victor, Aube). Oblong oval, depressed, 

 almost without pubescence, somewhat shiny ; head large, red with darker 

 disc ; thorax ferruginous with the sides lighter, sparingly punctured on 

 disc, strongly on borders, side margins strong, base impressed on each 



