Three places online to order monarch caterpillars and the accessories to raise them are Monarchwatch.org, Butterflystores.com and Butterflybushes.com. Kits include instructions and a pop-up cage to keep the growing caterpillars safe. Milkweed plants, which are the food for the growing caterpillars, may not be included.
Monarch populations have reached critically low levels and are possibly facing extinction, as of late 2015. The reason for their decline is not known, but experts speculate that pesticides killing off milkweed and environmental destruction are two primary causes. The U.S. Fish and Wildlife Service is considering listing the monarch as an endangered species. Raising and releasing captive monarchs, as well as planting milkweed, is encouraged.