84 THE PHILHYDRIDA. 



Philhydrida"^, or "lovers of water/^ lias been given 

 to the whole group. 



Although these beetles are generally of small size, 

 the group includes the largest of our water beetles, 

 and indeed one of the largest of British Coleoptera, 

 the Great Water Beetle [Hydrophilus piceus), which 

 usually measures about an inch and a half in length. 

 In its general form it somewhat resembles the Water 

 Beetles already described, but is considerably more 

 elongated, and more convex on its upper surface than 

 the Dytici. It is entirely of a shining black colour, 

 with a slight olive tint on the upper surface; each 

 elytron exhibits eight faint striae or impressed lines, 

 and three lines of minute impressed dots or punctures ; 

 and the lower surface of the thorax is thickly covered 

 with fine yellowish hairs. -* The centre of the sternum 

 is occupied by a prominent keel, which projects in 

 the form of a sharp spine beyond the point of inser- 

 tion of the hinder limbs; the latter and the inter- 

 mediate legs are compressed, fringed with bristles, 

 and converted into powerful paddles, whilst the ante- 

 rior legs are of the ordinary form, except that, in the 

 males, the last joint of the tarsi is dilated into a large 

 triangular plate. 



This fine beetle, although by no means so abun- 

 dant as the common Dyticus, may be met with in 

 still waters in many parts of the country in the spring 

 and early summer. Although so much larger than 

 any of our Dytici, it is a far less active insect. This 

 is partly owing to the inferior power of the legs, and 

 partly to the mode in which the creature uses them, 

 for instead of striking out boldly, with the limbs of 

 both sides at once, it paddles along with a motion like 

 * Gr. phileo, to love, hudor, water. 



