34 POND LIFE 



or often their younger days in water, and can be recognised by 

 the points mentioned : 



(1) The Neuroptera (dragon-flies, Two pairs of membraneous wings 



may-flies, caddis-flies, &c.) (lacelike). 



(2) The Lepidoptera (moths) . . Two pairs of wings covered with 



scales. 



(3) The Diptera (gnats, corethra, One pair of membraneous wings, 



&c.) one pair of degenerate wings 



(halters, little rods with knob- 

 bed ends). 



<4) The Coieoptera (beetles) . . One pair of membraneous wings, 



one pair of hardened wings 

 known as elytra. 



(5) The Hemiptera (bugs) . . . One pair of membraneous wings, 



one pair of wings partly hard- 

 ened. 



(6) Aptera (springtails) .... No wings at all. 



WATER-BEETLES 



Water-beetles are common inhabitants of all ponds and 

 streams. How contaminated and foul the water, or how large 

 or small the pond may be, makes little difference to the aquatic 

 Coieoptera as long as they are able to find the food they require. 

 The eggs are laid under water., the young larva hatch and live 

 in the same environment, but the pupa stage is nearly always 

 passed out of water. 



The aquatic beetles belong to three main groups : 



Characteristics Habits 



Hydradephaga, long antennae . Carnivorous and vegetarian. 

 Hydrophilidae, shorter antennae. Vegetarian and seldom carnivorous. 

 Oyrinidae, very short, broad an- Carnivorous and vegetarian, 

 tennae (live on water surface) 



THE HYDRADEPHAGA 



The largest of this family is the well-known Dytiscus, the 

 giant amongst British beetles. Although very savage, Dytiscus 

 only kills when it actually requires food. It swims slowly, 

 searching systematically for some unwary creature. A tadpole 

 may be resting amongst the weeds, and disturbed, blunder into 

 the beetle's "arms. 5 ' In a moment it is seized; swim how it 

 may, there is no chance to escape, although the victim, if large 

 .and strong, may drag its captor some distance. If Dytiscua 



