“Now, my dear boys, I think you know something about the life of the caddis fly. For a whole year of his life he is a crawling water insect, then, for about a single day, he is a lively fly.”
“How does the caddis larva first get into the water?” asked Frank.
“As an egg, Frank. The female caddis fly lays her eggs in the water. She sometimes even crawls down right into the water to lay them.
“A tiny caddis grub, no bigger than this pin-head, comes out of each egg. As soon as he hatches out, he begins to build his case, to eat, and to grow; and from the moment of his birth up to the closing up of his tube, he is scarcely a moment idle.”
Exercises on Lesson XIV.
1. Turn a caddis worm out of his case in the way described in the lesson. Place the insect in a saucer half filled with water, and make a rough sketch of it. 2. When you have finished your sketch, place the empty caddis case in the saucer, and watch how the creature gets into it. 3. Make two columns by drawing a line down the centre of a page of your note-book. In the first column, describe the structure of the caddis larva and fly; in the second, that of the cabbage caterpillar and butterfly. Compare them. 4. In the same way describe the mode of life of the caddis fly (Column 1), and of the white butterfly (Column 2).
APPENDIX.
HINTS TO TEACHERS.
BUDS.—Twigs of beech, horse-chestnut, lilac, and hawthorn ought to be taken in in December and placed in water. They should have as much warmth and light as possible.
Willow twigs (for catkins) might also be forced in this way.
SEEDS.—Seeds should be soaked for twenty-four hours and then sown in sawdust in boxes 4 inches deep. They should be sown in presence of the pupils.