Insect and Spider Identification: See-through Cocoon?, 0 by Midna8

Midna8 wrote:
I found a small green caterpillar with no special markings on it in my garden on the lettuce. I put it in a jar to see if I could raise it for fun. After a few days, it made what I'll call a cocoon. Except you can see right through it. It's very thin and looks like strands of silk. The picture I included is actually it in the cocoon, it's just so thin it doesn't even show up on camera. While that's interesting because I can see the transformation of this insect, it also makes me question if what I'm raising is a moth, a butterfly, or something a little more sinister (IE, more likely to bite or sting me). Can anyone tell me what this insect, found in Illinois, might be?