WILD CREATURES OF GARDEN AND HEDGEROW 



plants, or hidden in the mud, and clasps in a 

 fatal embrace any unfortunate tadpole that 

 comes near, is the water scorpion, 1 a flat-bodied 

 brown insect that you would never notice as it 

 lies waiting for its victims. Many other crea- 

 tures also prey on the tadpoles, but there are 

 such numbers that their ranks are not even 

 thinned. In the ponds, of which I wrote a page 

 or two back, they are so many that the water 

 in places is blackened by them. Sometimes a 

 stream of tadpoles will set out from one bank 

 of the pool to swim to the opposite side, when 

 they will appear like a dark ribbon across the 

 pond. Then you will see another lot swimming 

 along the side. What causes these move- 

 ments I cannot say, unless it is changes in 

 the temperature of the water. Perhaps they 

 have their own reasons which we cannot 

 understand. No doubt if a being from another 

 world was to look down on a London street 

 from above, he would wonder why the queer 

 little things in the streets below him went all 

 one way on one side of the street and the 

 opposite way on the other side. It is the toad 

 tadpoles of which I am speaking when I 

 mention the crowd movements, for the frog 



1 The Water Scorpion, Nepa cinerea. 

 110 



