Butterflies can often be identified by the chrysalises that they develop, each of which looks and hangs differently from a plant the creature likes to feed on. Identify a few different chrysalises with information from a butterfly conservatory curator in this free video on butterflies.
Butterflies actually make chrysalises which is a naked pupa and a cocoon is actually a sac around the pupa that protects it. So the pupal stage or the third stage in the life history of any complete metamorphosis in butterflies it's called a chrysalis. Chrysalises, every kind of butterfly has a different looking chrysalis and every species has a different looking chrysalis. Swallowtails typically when I hear chrysalis that will hang sideways and will have a lasso around that kind of holding it up, kind of like a lasso or a seatbelt. A lot of Brush-Footed butterflies when they hear chrysalis that will hang upside down from a little peg on the tip of it. That's called a cremaster and that will be on a little padded silk under a leaf or under a branch. A lot of butterflies spend the winter as a chrysalis and those chrysalises will look like a dried up piece of wood and will blend in with what you normally see in the winter time. Chrysalises can very from gold to green to brown. So Swallowtails typically will have a low, elongated chrysalis that's pointed at the tip. Monarchs as a lot of people are probably familiar with, have a green shiny chrysalis that looks like a piece of jewelry. Cabbage butterfly have a golden green chrysalises that are under the leaves. Pretty much most butterflies make their chrysalises around their host plant; so if you find a chrysalis on a certain plant that a butterfly would feed on, chances are that's a species of butterfly. Cocoons will be found from mobs and are found in trees and they will be wrap up in leaves or that they'll be able to ball a silk or sometimes they bury under the ground and make a pupa underneath the ground which is almost like a chamber that's got a cocoon holding the sleigh a lot of it.