If the eggs are near the hatching period the varnish will have scaled off, revealing the tiny white eggs; if not, let the teacher remove the varnish with a knife or pin, thus exposing the eggs. If the teacher has a lens the children should view the eggs through it. Exhibit the picture [Fig. 149], b, which represents the eggs greatly enlarged showing the net-work of cement which holds them in place. Ask the children to compare the shape of these eggs with that of bird's eggs, and bring out the fact that these are thimble-shaped. Then ask the pupils to guess what sort of mother laid these eggs, cemented them fast with a network, and then covered them with a coat of waterproof varnish. After sufficient interest is aroused on this point, explain to them: "One day last July a little moth or miller was flitting about the tree from which these twigs were taken. If we could have been there and caught her we should have found her a pretty little creature with four wings covered with down and a soft fuzzy body. In color she was a pale rosy-brown, and had two bands of pale yellow across each front wing." (Call attention to the picture of the moth, [Fig. 149], e.[25])
"This is the little mother which laid her eggs in a ring around the twig and covered them with a waterproof coat to keep them safe and sound until this spring, when they will hatch."
What will come out of these eggs when they hatch? The teacher should not answer this question, but let the pupils watch the eggs and discover the answer for themselves.
Place the twig with the egg-mass upon it in the bottle of water ([Fig. 147]). It will be best if this twig is a part of a forked branch, so that the caterpillars may make their web upon it ([Fig. 148]). As soon as the eggs hatch ask the following questions:
What sort of young ones hatch out of the eggs?
Are they like their mother?
What color are they?
Why are their heads so large? Answer. So that they can gnaw the lid off the egg and thus get out.
Why should the young ones of a pretty moth be little black caterpillars?
(Leave this answer for future investigation.)