182 adephaga. [HydrojKirus. 



considers that it will probably prove a variety of II. striola, Gyll., to 

 which species it bears an exceedingly close resemblance. 



K. palustris, L. Oblong oval, rather elongate, very strongly 

 pubescent, under side black, upper side fuscous with the head and sides 

 of thorax plainly red, the former more or less dark on each side of 

 vertex ; thorax closely punctured on disc, more strongly on margins ; 

 elytra closely punctured with the margins and markings at base and apex 

 of elytra more or less plainly testaceou.s ; occasionally, but rarely, these are 

 almost obsolete ; legs red ; male rather dull, but less so than female, the 

 latter sex with elytra more closely punctured ; anterior and intermediate 

 tarsi of male dilated, claws of former unequal. Long. 3|, lat. vix 

 2 mm. 



Ponds, &c. J common in stagnant water throughout the kingdom ; varieties 

 occasionally occur in which the testaceous spots are almost if not quite obsolete, and 

 the whole insect is of a reddish or fuscous colour. H. tinctus, Clark, is to be referred 

 to one of these : the specimens from which it was described were taken by Turner in 

 the New Forest. 



H. incog'nitus, Sharp. Very like the preceding, but larger and 

 broader with the pale markings less developed and not so distinct from 

 the ground colour ; moreover, the form is different and more like that of 

 H. erythrocephalus, the sides of the elytra being more rounded ; the 

 punctuation of the elytra is rather more distinct than in H. palustris, the 

 pubescence rather finer and more sparing ; the whole upper surface is 

 less opaque, and the tarsi are slender, the sexes being hard to distinguish ; 

 the prosternal process also is more slender. Long. 3f, average lat, 

 2 mm. 



Rare ; Cambridge ; a single specimen near Sheerness apparently referable to this 

 species (Champion) ; Northumberland ; Scotland, rare, Solway, Forth, Tay, Moray. 



This species is also closely allied to i7. var/epidus, Fairm., but is 

 distinct from it, being smaller, and having the distinction between the 

 sexes much less marked. 



K. erythrocephalus, L. Oval, convex, strongly pubescent ; head 

 red with the vertex on each side fuscous ; thorax black, with the margins 

 strongly and disc finely punctured, sometimes almost smooth, side margins 

 more or less obscurely reddish ; elytra fuscous with tlie side margins and 

 base lighter; legs red, antennse fuscous with base lighter; male with the 

 elytra closely but plainly punctured rather shining, with anterior and 

 intermediate tarsi dilated ; female dimorphic, one form being like male, 

 the other dall and obsoletely punctured : the latter form is the //. 

 deplanatus, Aube. Long. 4, lat. 2| mm. 



Ponds, &c. ; common and widely distributed throughout the kingdom. 



H. dereUctus, Clark, is a variety of this species with the sides of 

 elytra more parallel and the apex more acuminate ; the original specimens 

 came from the Orkneys, and Dr. Sharp has specimens from Inverness-shire ; 

 there appears, however, to be no real specific character to separate it. 



