474 HABITATIONS OF INSECTS. 



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- 

 known philosophical principles, she constructs for her- 

 self 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 

 slie 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 pre- 

 sents 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. Ck)thed 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 



