Hatching Cup with Access Plug & White Aspen Excelsior (Mildew-Resistant Wood Wool) Create the ideal environment for hatching praying mantis eggs with this ready-to-use hatching cup. Designed for convenience and optimal humidity control, this cup features an access plug for easy misting and inspection. The included white aspen excelsior—naturally mildew-resistant wood wool—provides a safe and secure perch for delicate mantis nymphs, supporting their development from the moment they emerge. Simply mist with clean water to maintain the perfect humidity level without the risk of mold or mildew.