MATERIALS OF PUPA CASES. 59 
by some kinds of larva, although they do 
not spin. 
Lucy. How do they contrive that, if 
they cannot spin ? 
Mother, The caterpillars, that do so, 
make a sort of matted web, of their own 
hair, and of the glutinous matter with 
which they are generally provided. Others 
form their cases by gluing pieces of leaves 
together. And those, which live in wood, 
gnaw that substance with their jaws into 
small particles, almost as fine as dust, and 
working these together with their own 
gum, form a strong case, so closely re- 
sembling the wood to which it is attached 
as to be with great difficulty distin- 
guished. 
Lucy, What a number of different 
ways there are of making these sur- 
prising little cases ! 
Mother, At present, I will mention 
but one more ; some of those, who fold 
back the leaf to make their little man- 
sion, when about to change, fill up the 
