Thanks so much for your interest in helping us. The larvae were ordered from Monarch Watch. We were very pleased when they arrived because they looked so healthy. They were of various sizes---this pleased us because we knew that we would be able to observe their growth and development. They died at various times, but generally as they got to the stage where I thought they would be J-ing. They appeared to stop eating which also did not alarm me. After dying, their bodies still had reasonably good color but were slightly darkened. One larva lived for four weeks after we received them, but he did not appear to eat or produce droppings in the last 10 days or so.
We did have the experience of tagging monarchs which we caught in the wild. We also learned that 2 of the monarchs we tagged last year were recovered in El Rosario, Mexico. Since about 35% of my students are Hispanic, this has special meaning to us. The project is not a total loss. We hope to try to rear monarchs again in the spring, although we realize that these will not migrate.
Thanks so much for your interest...I have fellow teachers and parents asking me if I have found out what happened. It is nice to have a project which has generated so much interest.