168 TRANSFORMATIONS OF INSECTS. 
moreover, peculiar movements, and especially that of curling them- 
selves up, and they do this for hours during the great heat of the 
day; if they are alarmed, they cock up the end of their bodies 
in a threatening manner, and the attitude doubtless frightens some 
of their disturbers. ‘The larve eat the leaves of most plants, and 
they collect together in colonies, and often do a great deal of 
mischief. 
When they have attained their full size, the larvae form cocoons 
with silk, and glue the threads together so as to make stout and 
hard cases; and some of them are to be seen stuck between the 
LARVA OF A SAW-FLY. 
twigs and leaves or upon the small branches, whilst others are 
placed in the ground. These ground cocoons, however, contain 
pieces of stone and dust. Every caterpillar, as soon as its cocoon 
is made, begins to transform itself into a chrysalis; but the saw- 
fly larvee remain inert and huddled up for several months after 
having made their snug and safe hiding-places. The metamor- 
phosis does not take place at once, but occurs some time or 
other during the winter or early spring; and when it is com- 
plete, the fly escapes, usually by cutting the end of the cocoon 
with its jaws, and, should it be a female, it soon begins to use 
the ovipositor. It flies to and fro, seeking a proper place to 
deposit its eggs in, and takes a great deal of pains to select a spot 
where the nourishment of the future larve will be at hand; and 
it is not simply satisfied, like the butterfly, with laying its eggs 
on or near the plant upon which the young are to feed. The 
