THE TYRANT OF THE POOL 33 



it is keeping a sharp look-out for prey. As 

 soon as it spies a victim the grub springs 

 through the water, curving its body like a 

 snake. At other times it creeps about on the 

 floor of the pool, or lurks amongst the thickets 

 of weeds and grasses beneath the water, like 

 a tiger in its lair, pouncing out and seizing 

 any little animal that passes by. 



At intervals the grub comes up to the top 

 of the water to take in a fresh supply of air. 

 At the end of its tail it carries two breathing 

 tabes which it pushes above the surface-film 

 when it wants to breathe. The grub is lighter 

 than the water, so when it wishes to come up 

 to the top it has only to release its hold on 

 the weeds, or stop swimming, and it floats to 

 the surface, tail first. 



But at last the Tyrant gives up its wicked 

 ways and rests for a time as a pupa. It crawls 

 out of the water and buries itself in the soft 

 mud at the edge of the pool. If it is summer- 

 time its sleep lasts only for a fortnight or so ; 

 but if it is late in the autumn the larva buries 

 itself more deeply in the bank and rests 

 quietly in its little cave all through the cold 

 weather, and does not turn to a pupa until 

 the following spring. Then in a week or two 



