148 TRANSFORMATIONS OF INSECTS. 
pierce into a leaf or a seed, and begin to mine. After a while, and 
when the caterpillars have grown to a certain size, they leave 
their solitary mine, eat through the skin of the leaf, and appear 
on the surface. They divide the leaf, and sew one part on to 
another, and make themselves a comfortable tube. So readily do 
these caterpillars make a protecting case, that they do not care 
COCOONS OF BRAZILIAN 77272e7na. 
much about repairing old ones, or enlarging their small homes ; 
on the contrary, they leave the old and take refuge in new leafy 
houses very constantly, after having eaten the best part of the 
former. Some eat grain, and, after having cleared out the interior 
of one, find in the skin a most convenient case. 
The last segment of the abdomen of the caterpillars of the Colco- 
phore is horny, and so is the second of the body, for this hardness 
of structure is much required by case-bearing insects, on account of 
the friction and pressure of the two ends of the tube. The pupze 
