How can you tell if a monarch butterfly pupa is dead?

Once the pupa dies, it will begin to turn color. Before it emerges, it turns black and the orange wings can be seen through the pupa shell. If it doesn't emerge within 24 hours of changing color, it is most likely dead. After 48 hours, it is dead. A brown or other color pupa (other than black/orange when it is preparing to emerge) is a dead pupa.