40 POND LIFE 



wings. The latter gradually make an appearance as the age 

 of the larva increases, whilst the small stumpy tail is replaced 

 by the tube as in the adult. 



When Nepa's " elytra " are expanded, and the membraneous 

 wings beneath exposed, it seems no longer so repulsive a 

 creature : the sides of its abdomen are brightly coloured. 



Water-scorpions seldom remain long in the aquarium unless 

 it be covered : on the approach of winter they hibernate, and 

 only return to " active " life the following spring. 



Although Ranatra Linearis lives a life very similar to Nepa, 

 yet its appearance is vastly different : its body is long and 

 very slender. The head, similarly to Nepa, has a prominent 

 sharp beak, and the bead-like eyes are conspicuously placed on 

 the sides of its head. If these two water-scorpions were com- 



Eared K Linearis would receive premier honours for agility, 

 ragility, and savage disposition, but all the same it is practi- 

 cally as sluggish as sluggish can be. 



When walking B. Linearis lifts itself up on its long legs, 

 thus giving the appearance of walking on stilts. Should it 

 leave the water it experiences a great deal of difficulty in 

 breaking the water-film. Its efforts are most amusing to the 

 biped onlooker, for the water-film is no easy thing to crack, 

 and the insect is so light and fragile, that everything seems to 

 be against the success of the undertaking. 



But water-bugs are not all of so sluggish a disposition as 

 Nepa and Ranatra. Notonecta or the water-boatman is very 

 common in certain districts and equally rare in others. Its 

 size depends on its age, but its appearance is similar whether 

 old or young, and as one might expect from its astonishing 

 name it resembles a boat, for its back is deeply keeled whilst 

 the underside of its body is flat. Thus Notonecta adds to the 

 similarity by swimming continually on its back. Its front legs, 

 which are never used for swimming, are held beneath its head, 

 ready to seize any little or large creature that it may meet 

 with; for size has no dimming effect on Notonecta's courage 

 should it be hungry. The front pair are also useful to hold on 

 to the weeds on which Notonecta is settled. The third pair 

 are used for swimming only, and are very long and fringed 

 with hairs. 



By means of well-timed, powerful strokes the little miniature 

 vivant boat is driven through the water. The second or 

 middle pair seem to be useful either to aid Notonecta whilst 

 swimming or to assist in holding on to the weeds when rest- 

 ing. But Notonecta, although settled, is far from asleep. In 

 fact the oars, held well out, are gently paddling, and its sharp, 



