Confusing Petrophila Moth (Petrophila confusalis) — These small and beautiful moths are pretty unique. Their larvae feed on algae on rocks in fast moving streams …yes, that’s right. The adult females dive into water (going up to about 15 feet deep) to lay 200 to 300 eggs. They carry a shell-like layer of air on their body to enable them to breathe under water for 4 to 12 hours. Photo by Glenn Marangelo on 7/29/17 near Florence, MT.