HABITATIONS OF INSECTS. 4? 71 



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 

 this 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 

 air beneath the roof prepared for its reception. This 

 manoeuvre she repeats ten or twelve times, until at length 

 in about a quarter of an hour she has transported as 

 much air as suffices to expand her apartment to its in- 

 tended extent, and now finds herself in possession of a 

 little aerial edifice, I had almost said an enchanted pa- 

 lace, affording her a commodious and dry retreat in the 

 very midst of the water. Here she reposes unmoved by 

 the storms that agitate the surface of the pool, and de- 

 vours her prey at ease and in safety. Both sexes form 



