52 LETTERS ON ENTOMOLOGY. 
enlarge it as they grow, and this is the most 
difficult thing they have to do. We can easily 
imagine that they can add to the length, but not 
how they let it out at the sides. This they per- 
form by slitting down the side about a quarter 
of the length (for if they did it all at once it 
would fall off), and putting in a little piece like 
a gore; they proceed with another, till they 
come to the end. This may be very plainly 
discovered by taking the insect from a blue cloth 
and putting it on a red one, when the additions 
will be all red. They have different modes of 
doing it, however, but all equally ingenious. 
Should not this make us sometimes ashamed of 
our own want ot contrivance ? 
As these insects turn to moths every year, 
there are always plenty of their empty coats, 
which the young ones prefer taking to pieces for 
their own, to the cloth itself, as the materials are 
all prepared ; thus those born on green or blue 
cloths are sometimes clothed in quite different 
ccljurs, where there have been old insects be- 
fore : in consequence, it is very rare to find these 
coats in good condition. They also show a great 
deal of taste ; for it has been observed that, on 
a gray colour or brown cloth, the little creatures 
are dressed in bright red or blue ; and on ex- 
