As with rearing any captive animal, the goal is to most closely mimic the animal s native habitat and environmental conditions. There are only a few critical factors for successfully raising mantids, and disregarding even one of these for just a few days may result in death. For habitats , I use vials of various sizes. Ideally, you will use one that is 3X the height of a mantid, and 2X as wide. Temperature requirements vary slightly with most species.
Room temperature is fine for most species, although tropical species do better in warmer habitats.
You must maintain a constant moderate level of humidity though, as oothecae are VERY susceptible to drying out. Also, it is best to hang the ootheca from the top of the container, as the mantids will use gravity to aid their hatching. Temperature and ventilation will affect how long it takes for the paper to dry. Now, you don't want so much water vapor in there that it is collecting and remaining on the sides. I like to provide as much ventilation as possible for my mantids, but the trick is to keep the humidity up, so cross-ventilation is a key factor.