Enough has been written about Danaus plexippus on the internet (including here on my blog in previous years). Here are a few pictures I really like.
sipping whilst upside-down
backlit
Big Butterflies #4: The Monarch
Elizabeth's Wildflower Blog
hunting in the Maryland piedmont (mostly)
Elizabeth's Wildflower Blog 
You are so lucky to have such wonderful butterflies. Over here in the UK we have a more limited range and numbers are rather low this year. I really appreciate the quality of the photographs and am always interested in your blogs -thank you for writing them.
Best wishes
Peter W
And thank you for saying so! It means a lot to me.