tfANDBOOK OF BEETLES. 



43 



very small apterous yellowish beetles, found on the seashore 

 at low-water mark; and as they are covered by the water 

 for several hours every day, they may fairly be regarded as true 



Aepus RoUnii. (Mag.) 



marine insects. They are sometimes accompanied by Aepo- 

 pkihis Bonnairei, a small insect of very similar appearance and 

 habits, but belonging to the Order Hemiptera, or Bugs 



The Hydradephaga, or carnivorous 

 Water-Beetles, include the two families 

 Dytiscida and Gyrinida. The Dytis- 

 tidce may be known from other water 

 beetles by their long, slender antennae, 

 short palpi, and the structure of their 

 legs. The front pair of legs is generally 

 short, with the basal joints of the tarsi 

 more or less dilated, at least in the 

 males ; in one group (the Hydroporides) 

 the four front tarsi are only four-jointed. 

 The largest and some of the commonest 

 of the Dytiscidcs belong to the typical 

 genus Dytiscus. They are olive green, 

 or brown, with yellowish borders to the 

 thorax and elytra. Water-beetles^ are 

 generally very smooth and shining, 

 but the elytra of Dytiscus, and several 



Nat. Size. ( 



allied genera, are furrowed in the female. The Dytisci arc 



