Instructions
Place your egg case outside or in a terrarium (if you intend to keep some as pets). Your can fashion a terrarium out of any container--a jam jar or a fish bowl, for example--as long as you leave a small branch inside for the nymphs to climb. Place mesh over the top that prevents nymphs from escaping but allows for food delivery and air flow.
Keep your egg case at a temperature of about 67 to 78 degrees Fahrenheit and out of direct sunlight. Inside, this is best achieved by a heating mat. Outside, hang the egg case in the shade.
Maintain a humid atmosphere. Mist your terrarium lightly with water every day. If the proper conditions are maintained, your egg case should hatch in approximately 3 to 6 weeks.
When they hatch, a single egg case can hold anywhere from 50 to 200 praying mantis nymphs. If you intend to keep some as pets, release all but a few nymphs within the first two days.
Feed your future pets with small insects at first--aphids and flies, for example. Your nymphs will grow quickly, as will their appetite; adjust their portions and diet accordingly.
How to Hatch a Praying Mantis
If anything, praying mantises are known for one thing: that the female devours the male after mating. They have other beneficial qualities, however: not only can they make charming pets, but a steady population of mantises in your garden can easily reduce the local pest population. Before praying mantises can be raised, however, they must first be hatched.