First of all I know you’ve heard this a million times but I love your website, it is more encompassing than any bug identification book. Anyway, I ran across this little caterpillar today and don’t know what it is, I would be thankful if you could identify it for me. I may keep it and see what it turns into if you can’t. Its about an inch long and was found on a wild willow tree near my pond. Thanks in advance.
Your caterpillar is most definitely in the genus Limenitis. It is a dead ringer for a Viceroy Caterpillar image on BugGuide. The Viceroy Butterfly is best known for being a mimic of the Monarch. In human society, that would be termed an imposter.