AND THE CHILDREN. 
33 
This, however, is the section of a bee. But there is 
not very much difference as to the trachea . 
(a) is the nervous cord, (b) the intestine, (c) the heart, 
and (d) the tracheae. Notice how the little tubes spread 
to all parts of the body. 
Now examine the head again. You remember that 
I said the larvae live on the leaves of plants, so, of course, 
they must have mandibles with which to bite the leaves. 
Notice two horny little things on each side of the 
trunk. That is all that is left of the mandibles or pinchers 
as you would call them. 
The butterfly does not need mandibles , because the 
food he eats is of such nature as does not require biting. 
Take the wings very lightly between the thumb 
and forefinger, rub them just a little, now look at them. 
Your fingers are covered with a kind of dust, are they 
not? 
