Danaus gilippus in Massachusetts

[Mothman617]

I had a rather unusual sighting today of Danaus gilippus (Queen) in Topsfield,
Essex Co. Massachustts on July 7, 1999. It was a slightly worn female
depositing eggs upon Swamp Milkweed. I have seen and collected this species in
Florida where it is quite common. In current literature there is no mention of
this butterfly migrating northward from its current range. This is most
definately a stray and the fact of this laying eggs upon this Milkweed means
there will be a local population of this butterfly perhaps. I followed her
around and collected some of the ova upon the leaves to rear a few. I was
wondering if anyone else has seen this butterfly this far north, if so it would
be interesting.