FLOATING ARK OF WATER-BEETLE. 11 



On other evenings she will take wing, and speed 

 her way whither no eye can follow ; but now, she 

 has another and the most important duty of her 

 existence to perform, and her customary evening 

 ramble is not permitted to interfere with its fulfil- 

 ment. On watching her closely we find her busy 

 at some self-imposed occupation; what is its 

 nature? To discover that, she must be closely and 

 patiently watched. At her tail are a couple of 

 spinning organs, which move from right to left 

 and up and down with great swiftness, all the 

 while a glutinous fluid, which hardens into a 

 thread, being discharged from each of them. 

 With this apparatus the industrious insect is spin- 

 ning a pouch not unlike the purses which were in 

 fashion before the long ones that ladies knit came 

 to be adopted. This purse is three quarters of 

 an inch long ; it consists outside of a tissue, like 

 parchment, which is quite impervious to water, 

 but is lined inside with the most beautiful, light, 

 downy material possible, which is as white as 

 snow. There is a sort of little horn to this pouch, 

 which admits the air, but the opening to which is 

 protected by a layer of cross threads, which ex- 

 cludes the wet. In three hours of patient toil 



