i see that a lot of people are confused about the treasures, i found all 12, and considering it's the one i found last i am like 90% sure this is the problem one. in the first room where you can get turned into a female eggbug, you can backtrack through to the room where you first encounter female eggbugs, and fly up off the top of the screen to find a hidden one. most of the others are in pretty obvious locations.