Monarch caterpillars ingest the toxins from the milkweed they eat.
This provides a certain amount of protection from birds which become ill after eating a monarch, and learn to avoid them. When startled, the caterpillar will rear its head backwards and extend a set of horn-like projections which also produce a foul odor. Some chrysalises which form in the fall will overwinter in this pupal state and emerge as adults in the spring. You may give each page an identifying name on the next line.