HALIPLUS AND CNEMIDOTUS. 61 



reddish-browu, lighter and redder in the middle. The anterior 

 margin of the thorax has a black stripe in the middle, while a 

 similar stripe on the posterior margin is widened so as to form 

 two black lobe-like marks on the thorax. The elytra are black, 

 and on each elytron are six spots of the same colour as the 

 middle of the head, three of the spots running parallel with 

 the sutm'e, and the other three being placed along the margin. 

 Beneath, the body is yellowish. 



This pretty little Beetle is exceedingly common in some 

 places, and correspondingly rare in others. Although the spots 

 differ much in size and shape, and in some specimens are even 

 fused into each other, there is no difficulty in recognising the 

 insect. 



Our next example of the Hydradephaga is Haliplus varie- 

 gatus, an insect which is shown on Woodcut No. VI. Fig. 3. 



Like the last species, this is a pretty little Beetle, and 

 exceedingly variable in its colour, so variable indeed that it 

 has been described by the same writer under the name of at 

 least two species. It is a very small insect, not quite one-sixth 

 of an inch in length. Its usual colour is as follows : — The head 

 is dark brick-red, deepening into blackish-brown on the top. 

 The thorax is paler than the head. The elytra are rather con- 

 vex, sharply pointed, deep reddish-brown in colour, and have 

 some blackish spots near the margin. This variety is common ; 

 but there is one which is much rarer, and in this the general 

 hue is greyish-yellow, and the whole insect altogether lighter 

 in colour. The brightest-coloured specimens are found in 

 rather swift streams running through a gravelly soil. 



There are eleven British species belonging to this genus. 



On Woodcut No. VI. Fig. 4, is shown another of these prettily- 

 coloured but variable Water Beetles. Its name is Cnemidotus 

 ccesus, and it has a vast amount of detail in its colour, in 

 spite of its small size, which does not exceed one-sixth of an 

 inch. The general colour of the insect is light-yellow, the 

 head is punctated, and upon the base of the thorax is a curved, 

 punctated impression. In order to see the markings on the 

 elytra, or indeed to see any part of the markings properly, a 

 good lens is required. When viewed with such assistance, the 



