PONDWEED CATERPILLAR. 39 
egg, it cuts out a piece of leaf, and by 
means of its silken spinning fastens this 
bit round the edges to another part of 
the same leaf, leaving a few openings by 
which to creep out and feed. When it 
grows too large for this first habitation, 
it cuts out another circle of the leaf, and 
makes a second suitable to its size; as it in- 
creases, it thus constructs new dwellings, 
till it changes to a pupa, which, from its 
lightness, floats upon the surface of th« 
water. 
Lucy, As long as it remains a little 
chrysalis it may swim ; but the poor fly, 
what saves it from the water ? 
Mother, When the fly bursts its nar- 
row cell, it creeps out, and, resting upon 
the empty chrysalis, as it were upon a 
boat, remains there till strong enough for 
flight, when it becomes an inhabitant of 
the air. 
Lucy, How beautiful to see it spring^ 
from its light boat and fly away ! What 
a number of different kinds you have al- 
ready described ; and 1 dare say there are 
