THE WATER CABINET. 129 
in an instant what is the use of his case, for his soft 
nakedness is no sooner exposed, than the minnows finish 
him, and find the flavour excellent. But to see a cad in 
his proper uniform molested is a very rare sight indeed. 
He passes his larva life innocently, and is an amusing 
fellow ; when he feels the numbness of death creeping over 
him, the cad draws in his six legs, and sets to work inside 
to weave a winding-sheet and to shut the shutters, for he 
knows that his time is come, and there is no one to do 
such melancholy offices for him. All alone in his solitary 
cell, the hermit works day and night, and hourly his 
fingers grow more feeble. We look and find the shutters 
closed, and by this time the larva has changed into a pupa. 
GRATING OF CASE-WORM, MAGNIFIED. 
The mode in which the worm closes its cell is curious 
enough. Over its entrance it weaves a grating of silk, 
which hardens in water and remains insoluble. It may 
be seen very plainly by the naked eye, but under a good 
lens increases in interest. The grating is placed a little 
inside the margin of the opening, and fits exactly within 
it, and its object is to protect the pupa from invasion, 
E 
