What kind of lid will you use? Pygmies like humidity, so I wouldn't recommend a screen lid. I'd use a glass lid with some ventilation, such as the hinged aquarium lids with the plastic strip along the back. You can either drill holes in the plastic or cut out a section and glue a piece screen to cover the opening.
Be sure to mist regularly, but don't let it stay wet. My rule of thumb is that in an air conditioned house, if there is condensation on the glass in the morning before the lights come on, the humidity is about right. I open the enclosure every day to check on my pygmies and feed them, which allows fresh air into the enclosure. If you have this kind of set up and the humidity is right, you shouldn't need to mist every day and I only mist enough to give them water to drink on the leaves.
