474 HABITATIONS OF INSECTS. 



and is an admirable diver, she not unfrequently hunts on 

 shore, and, having caught her prey, plunges with it to the 

 bottom of the water. Here it is she forms her singular 

 and unique abode. She would evidently have but a very 

 uncomfortable time were she constantly wet, but this she 

 is sagacious enough to avoid ; and by availing herself of 

 some well-knoAvn philosophical principles, she constructs 

 for herself an apartment in which, like the mermaids and 

 sea-nymphs of fable, she resides in comfort and security. 

 The following is her process. First she spins loose 

 threads in various directions attached to the leaves of 

 aquatic plants, which may be called the frame-work of 

 her chamber, and over them she spreads a transparent 

 varnish resembling liquid glass, which issues from the 

 middle of her spinners, and which is so elastic that it is 

 capable of great expansion and contraction; and if a 

 hole be made in it, it immediately closes again. Next 

 she spreads over her belly a pellicle of the same mate- 

 rial, and ascends to the surface. The precise mode in 

 which she transfers a bubble of air beneath this pellicle 

 is not accurately known ; but from an observation made 

 by the ingenious author of the little work from which 

 his account is abstracted, he concludes that she draws 

 the air into her body by the anus, which she presents to 

 the surface of the pool, and then pumps it out from an 

 opening at the base of the belly between the pellicle and 

 that part of the body, the hairs of which keep it extended. 

 Clothed with this aerial mantle, which to the spectator 

 seems formed of resplendent quicksilver, she plunges to 

 the bottom, and, with as much dexterity as a chemist 

 transfers gas with a gas-holder, introduces her bubble of 



