http://www.panda.org/who_we_are/wwf_off ... ews/?22791
Okay, look at the picture of the Monarch on the right. It isn't a boy. Boys have thin veins on their upper wings. Right. This one has thick veins, but it also has the dots on the lower hind wing.
http://www.turismosustentavel.org.br/wh ... -butterfly
This may be a better shot.