Handbook of Nature-Study · Lesson LXXIII · Topic 9: Butterflies and moths
73. The cecropia moth
Goal: Your child can find a cecropia cocoon in winter, explain how it protects the pupa, and describe the giant moth that comes out in spring.
You'll need
- A winter walk among bare shrubs and small trees
- A screened box kept outdoors in shade (optional, for one cocoon)
- The book's photographs of the cocoon, the caterpillar and the moth
- A nature notebook and a pencil (colored pencils if you have them)
What's in the book
Comstock's story of America's native giant silkworms compared with the Chinese silkworm, and the life of the cecropia: the moth's eggs, the big green caterpillar with blue, yellow and orange knobs, its molts, and its cocoon. Photographs show a cocoon cut open and a moth just out. Lesson LXXIII has questions on the cocoon, pupa, moth and caterpillar.
The lesson, step by step
When and where
Late fall and winter, after the leaves drop. Comstock's method: "It is best to begin with the cocoons, for these are easily found after the leaves have fallen." Look for a big, baggy, brown cocoon, about three inches long, fastened along a twig of a shrub or small tree. The moths come out in late spring.
A change from the book
Comstock asks children to cut open a cocoon and take the pupa out. We don't do that: it can kill the pupa. Use her photograph of a cut-open cocoon instead.
If you bring one cocoon home, leave it on its twig and keep it outdoors in a screened box in the shade, as Comstock also advises, so the moth comes out at the right time. Let the moth go outdoors the evening it comes out.
Keep the big idea in mind
Comstock's "leading thought" is the one idea the lesson is meant to lead to. Read it to yourself now, and save it to share at the end, after your child has looked and answered:
The cecropia moth passes the winter as a pupa in a cocoon which the caterpillar builds out of silk for the purpose. In the spring the moth issues and lays her eggs on some tree, the leaves of which the caterpillar relishes. The caterpillars are large and green with beautiful blue and orange tubercles.
The cocoon
How does the cocoon look on the outside? What is its general shape? To what is it fastened? Is it fastened to the lower or the upper side of a twig? Are there any dried leaves attached to it?
Where do you find cecropia cocoons? How do they look on the tree? Are they conspicuous?
The way out
Are both ends of the cocoon alike? Do you find one end where the silk is not woven across but is placed lengthwise? Why is this so? Do you think that the moth can push out at this end better than at the other?
Look at the book's cut-open cocoon: an outer wall, loose silk in between, and a snug inner case.
The moth
If your moth comes out, or using the photographs:
Describe how the crumpled wings spread out and dry.
Do the moths eat anything? Why do they not need to eat?
The grown moth has no working mouth. It lives only a week or two, long enough to find a mate and lay eggs. Then read the leading thought aloud.
Nature notebook
Comstock suggests: "Make a water-color drawing or describe in detail the fully expanded moth, showing the color and markings of wings, body and antennæ." Paint it from life or from the book, and draw the cocoon on its twig beside it.