COLEOPTERA. 255 



the earth. Imago with antennae more or less clavated, 

 short, and generally concealed ; the maxillary feelers being 

 employed as antenna ; form elongate. Inhabits the banks 

 of ponds and rivers, among aquatic plants on which it 

 feeds ; enclosed in a bubble of air, it crawls on water-plants 

 and on the surface of water, with the back downwards, but 

 does not swim. Hydrana, Helophorus, Hydrochus, Geo- 

 ryssus, Elmis, Parnus, Heterocerus. 



Water-fleas or Gyrinites. Larva with strong arcuate 

 mandibles ; a long fleshy process, fringed with hair, rising 

 from both sides of each segment ; carnivorous, aquatic, na- 

 tatory. Pupa changes at the edge of ponds. Imago with 

 short clavated antenna ; mandibles short and obtuse, but 

 strong ; maxilla somewhat obtuse ; galea palpiform, exar- 

 ticulate; fore legs long, middle and hind legs short and 

 incrassated ; carnivorous. Inhabits water, performing in 

 the sunshine its beautiful and social gyrations on the sur- 

 face. Gyrinus. 



Carnivorous water-beetles or Dytiscites. Larva with 

 strong arcuate mandibles, perforated at the extremity for 

 suction ; carnivorous, aquatic, natatory. Pupa changes in 

 the earth, at the margins of ponds, among roots of trees 

 and grass. Imago with filiform antenna ; mandibles short 

 and strong ; maxilla arcuate and very acute ; galea palpi- 

 form and articulate ; the fore tarsi patellated in the males ; 

 the middle and hind legs flattened and ciliated ; form oval. 

 Inhabits water, feeding on aquatic animals ; swims with 

 great ease and swiftness, moving the corresponding legs 

 simultaneously. Acilius, Dytiscus, Colymbetes, Noterus, 

 Hydrophorus. 



Ground-beetles or Carabites. Larva with strong arcuate 

 mandibles ; active and carnivorous. Inhabits roots of grass, 

 rubbish-heaps, decaying vegetables, moss, under stones, 

 &c., in which situations it pursues and seizes its prey. Pupa 



