Anna Botsford Comstock, Handbook of Nature-Study, New York, Vail-Ballou Press, 1957, p. 409-410.
The caddis worm case protects its inmate in two ways, first, from the sight of the enemy, and second, from its jaws. A fish comes along and sees a nice white worm and darts after it, only to find a bandle of unappetizing sticks where the worm as. All of the hungry predatory creatures of the pond and stream would be glad to get the caddis worm, if they knew where it went. Sometimes caddis-worm cases have been found in the stomachs of fishes.
While it is difficult to see the exact opearation of building the caddis-worm house, the general procceding may be readily observed. Take a vigorous half-grown larva, tear off part of the sticks and bits of leaves that make the log cabin, and then place the little builder in a tumbler with half an inch of water at the bottom, in which are many bright flower petals cut into strips, fit for caddis lumber. In a few hours the little house will look like a blossom with several rows of bright petals set around its doorway.
Leading Thought- The caddis worms build around themselves little house out of bits of sticks, leaves, or stones. They crawl about on the bottom of the pond or stream protected from sight, and able to withdraw into their houses when attacked. The adults of the caddis worm are winged mothlike créatures which come in numbers to the light at night.
Method- With a dip net the caddis worms may be captured and then may be placed in the school aquarium. Duckweed and other water plants should be kept growing in the aquarium. the log-cabin species is best for this study, because it lives in stagnant water and will therefore thrive in an aquarium.
Observations- 1. Where do you find the caddis worms ? Can you see them easily on the bottom of the Stream or pond ? Why ?
2. Of what are the caddis-worm houses made ? How many kinds have you ever found ? How many kinds of material can you find on one case ? Describe one as exactly as possible. Find an empty case and describe it inside. Why is it so smooth inside ? How is it made so smooth ? Are all the cases the same size ?
10. How does the caddis worm build its case ? Watch one when it makes an addition to its case, and describe all that you can see .