Once people in America took many of these easily reared silk moths, in which the caterpillars spin beautiful silken cocoons, and tried to use them to raise silk for sale. It was possible to produce fine silk all right, but they found that the cost of American labor was so much higher than Oriental labor for producing this silk that it was impossible to compete. So the attempt was abandoned.
Clear from the eastern edge of the Great Plains to the Atlantic Coast and north to southern Canada, the Promethia moth wings its way through the dusk of summer evenings. Its dark colors, darkest in the male, merge it perfectly with the deep shadows and apparently are its primary protection against night hawks and other birds that might try to seize it since it does not have nearly so large and prominent “eyes” in the wings as the other silk moths.
The beautiful blue-green caterpillars have six bright red tubercles on the back, four near the front and two near the tail. Since red is almost universally a sign of warning among insects, this red is probably a signal to birds and other creatures that the Promethia caterpillar is poisonous. It lives on the leaves of many deciduous trees and bushes, including the laurel, the wild cherry, and the spicebush. Sometimes the adult is called the Spice Bush Silk Moth because it is found so much around the spice-bush, and the cocoon is often hung on the branches of that bush.