We have had a number of requests to help gardeners identify whether they actually have monarch butterflies on their milkweed. Confusion arises because monarchs look a lot like viceroys. So here’s the difference:
MONARCH VICEROY
Once you see the horizontal lines on the viceroy, identification is a piece of cake.
The story goes that the monarch butterfly was named in honour of King William III of England (ruled from 1682) who was originally the Prince of Orange in the Netherlands, orange being the predominant colour of the butterfly.
A viceroy is someone who rules in the name of the monarch. The butterfly acquired its name because it is smaller than the monarch.
There is a wonderful article on monarchs vs. viceroys on this New Jersey Audubon site.