Incredible info on diseases with photos.http://www.mymonarchguide.com/2007/07/d ... spore.htmlhttp://www.learnaboutmonarchs.com/learn ... spore.htmlhttp://www.butterflyfunfacts.com/oe.phphttp://www.uga.edu/monarchparasites/whatisOE/index.html
How to tell if butterflies are infected with OE
An infected pupa may develop dark spots or blotches two or three days before the butterfly emerges. These abnormal dark areas are parasite spores. Spores form on the eyes, antennae, wing veins, but mostly on the abdomen. You can see the spores through the outside layer of the pupa a day or two before pigments that color the butterfly normally darken the pupa. Before a butterfly emerges from the chrysalis, pigments are laid down coloring the scales that cover the butterfly. This normal change in the color of the pupa is symmetrical. The color change of an infected monarch happens earlier and does not create a balanced pattern on the pupa.
But, your caterpillar could have a parasite:http://www.mymonarchguide.com/2008/01/d ... d-fly.html
Watch for a fly larvae to burrow its way out of the caterpillar of pupa.