THE FRESH WATERS 183 



water-spider who is particularly admirable, so 

 we shall henceforth say "she." She spins a 

 flattish web beneath the water, and moors it 

 with silk threads like tent-ropes to stones and 

 weeds. A special line runs up to the surface 

 and is fixed to a floating plant. Up and down 

 this rope the spinner goes many times; at the 

 surface she gets air entangled in the hairs of 

 her body; she climbs down, looking like a 

 drop of quicksilver in the water the air 

 glistens so; she brushes her hair with her legs, 

 and the air-bubbles are caught underneath the 

 web, which thus becomes buoyed up like a 

 dome or like an anticipation of a diving-bell. 

 After many journeys up and down the web is 

 full of dry air, and there the spider deposits 

 her eggs and rears her young. Sometimes 

 when she is in a hurry she gets into the empty 

 shell of a water-snail and manages, we do not 

 quite know how, to fill it with air brought 

 down from the surface. There are many in- 

 teresting facts about the water-spider, for in- 

 stance, how she arranges tags of silk among 

 her hair, which probably help in entangling 

 the air-bubbles. For reasons, rather difficult 

 to explain, she never gets wet. But the big 

 interest is just that this spider found an empty 



